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  • 1.
    Abrehdary, M.
    et al.
    Royal Inst Technol KTH, Div Geodesy & Satellite Positioning, S-10044 Stockholm, Sweden..
    Sjöberg, L. E.
    Royal Inst Technol KTH, Div Geodesy & Satellite Positioning, S-10044 Stockholm, Sweden..
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS. Royal Inst Technol KTH, Div Geodesy & Satellite Positioning, S-10044 Stockholm, Sweden..
    Modelling Moho depth in ocean areas based on satellite altimetry using Vening Meinesz-Moritz' method2016In: Acta Geodaetica et Geophysica, ISSN 2213-5812, Vol. 51, no 2, p. 137-149Article in journal (Refereed)
    Abstract [en]

    An experiment for estimating Moho depth is carried out based on satellite altimetry and topographic information using the Vening Meinesz-Moritz gravimetric isostatic hypothesis. In order to investigate the possibility and quality of satellite altimetry in Moho determination, the DNSC08GRA global marine gravity field model and the DTM2006 global topography model are used to obtain a global Moho depth model over the oceans with a resolution of 1 degrees x 1 degrees. The numerical results show that the estimated Bouguer gravity disturbance varies from 86 to 767 mGal, with a global average of 747 mGal, and the estimated Moho depth varies from 3 to 39 km with a global average of 19 km. Comparing the Bouguer gravity disturbance estimated from satellite altimetry and that derived by the gravimetric satellite-only model GOGRA04S shows that the two models agree to 13 mGal in root mean square (RMS). Similarly, the estimated Moho depths from satellite altimetry and GOGRA04S agree to 0.69 km in RMS. It is also concluded that possible mean dynamic topography in the marine gravity model does not significantly affect the Moho determination.

  • 2.
    Abrehdary, Majid
    et al.
    Department of Environment and Life Sciences, Geomatics Section, University of Karlstad, Karlstad,Sweden; Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Lars, Sjöberg
    Division of Geodesy and Satellite Positioning, Royal Institute of Technology(KTH), Sweden.
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Sampietro, Daniele
    GReD s.r.l., Como, Italy.
    Towards the Moho depth and Moho density contrast along with their uncertainties from seismic and satellite gravity observations2017In: Journal of Applied Geodesy, ISSN 1862-9016, E-ISSN 1862-9024, Vol. 11, no 4, p. 231-247Article in journal (Refereed)
    Abstract [en]

    We present a combined method for estimating a new global Moho model named KTH15C, containing Moho depth and Moho density contrast (or shortly Moho parameters), from a combination of global models of gravity (GOCO05S), topography (DTM2006) and seismic information (CRUST1.0 and MDN07) to a resolution of 1° × 1° based on a solution of Vening Meinesz-Moritz’ inverse problem of isostasy. This paper also aims modelling of the observation standard errors propagated from the Vening Meinesz-Moritz and CRUST1.0 models in estimating the uncertainty of the final Moho model. The numerical results yield Moho depths ranging from 6.5 to 70.3 km, and the estimated Moho density contrasts ranging from 21 to 650 kg/m3, respectively. Moreover, test computations display that in most areas estimated uncertainties in the parameters are less than 3 km and 50 kg/m3, respectively, but they reach to more significant values under Gulf of Mexico, Chile, Eastern Mediterranean, Timor sea and parts of polar regions. Comparing the Moho depths estimated by KTH15C and those derived by KTH11C, GEMMA2012C, CRUST1.0, KTH14C, CRUST14 and GEMMA1.0 models shows that KTH15C agree fairly well with CRUST1.0 but rather poor with other models. The Moho density contrasts estimated by KTH15C and those of the KTH11C, KTH14C and VMM model agree to 112, 31 and 61 kg/m3 in RMS. The regional numerical studies show that the RMS differences between KTH15C and Moho depths from seismic information yields fits of 2 to 4 km in South and North America, Africa, Europe, Asia, Australia and Antarctica, respectively.

  • 3.
    Abrehdary, Majid
    et al.
    Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Sjöberg, Lars E.
    Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS. Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Combined Moho parameters determination using CRUST1.0 and Vening Meinesz-Moritz model2015In: Journal of Earth Science, ISSN 1674-487X, E-ISSN 1867-111X, Vol. 26, no 4, p. 607-616Article in journal (Refereed)
    Abstract [en]

    According to Vening Meinesz-Moritz (VMM) global inverse isostatic problem, either the Moho density contrast (crust-mantle density contrast) or the Moho geometry can be estimated by solving a non-linear Fredholm integral equation of the first kind. Here solutions to the two Moho parameters are presented by combining the global geopotential model (GOCO-03S), topography (DTM2006) and a seismic crust model, the latter being the recent digital global crustal model (CRUST1.0) with a resolution of 1A(0)x1A(0). The numerical results show that the estimated Moho density contrast varies from 21 to 637 kg/m(3), with a global average of 321 kg/m(3), and the estimated Moho depth varies from 6 to 86 km with a global average of 24 km. Comparing the Moho density contrasts estimated using our leastsquares method and those derived by the CRUST1.0, CRUST2.0, and PREM models shows that our estimate agrees fairly well with CRUST1.0 model and rather poor with other models. The estimated Moho depths by our least-squares method and the CRUST1.0 model agree to 4.8 km in RMS and with the GEMMA1.0 based model to 6.3 km.

  • 4.
    Abrehdary, Majid
    et al.
    Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Sjöberg, Lars E.
    Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS. Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), Stockholm, Sweden.
    The spherical terrain correction and its effect on the gravimetric-isostatic Moho determination2016In: International Journal of Geophysics, ISSN 1687-885X, E-ISSN 1687-8868, Vol. 204, no 1, p. 262-273Article in journal (Refereed)
    Abstract [en]

    In this study, the Moho depth is estimated based on the refined spherical Bouguer gravity disturbance and DTM2006 topographic data using the Vening Meinesz-Moritz gravimetric-isostatic hypothesis. In this context, we compute the refined spherical Bouguer gravity disturbances in a set of 1° × 1° blocks. The spherical terrain correction, a residual correction to each Bouguer shell, is computed using rock heights and ice sheet thicknesses from the DTM2006 and Earth2014 models. The study illustrates that the defined simple Bouguer gravity disturbance corrected for the density variations of the oceans, ice sheets and sediment basins and also the non-isostatic effects needs a significant terrain correction to become the refined Bouguer gravity disturbance, and that the isostatic gravity disturbance is significantly better defined by the latter disturbance plus a compensation attraction. Our study shows that despite the fact that the lateral variation of the crustal depth is rather smooth, the terrain affects the result most significantly in many areas. The global numerical results show that the estimated Moho depths by the simple and refined spherical Bouguer gravity disturbances and the seismic CRUST1.0 model agree to 5.6 and 2.7 km in RMS, respectively. Also, the mean value differences are 1.7 and 0.2 km, respectively. Two regional numerical studies show that the RMS differences between the Moho depths estimated based on the simple and refined spherical Bouguer gravity disturbance and that using CRUST1.0 model yield fits of 4.9 and 3.2 km in South America and yield 3.2 and 3.4 km in Fennoscandia, respectively.

  • 5.
    Agha Karimi, Armin
    et al.
    KTH.
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences. KTH.
    Huremuz, Milan
    KTH.
    Multidecadal sea level variability in the Baltic sea and its impact on acceleration estimations2021In: Frontiers in Marine Science, E-ISSN 2296-7745, Vol. 8, article id 702512Article in journal (Refereed)
    Abstract [en]

    Multidecadal sea level variation in the Baltic Sea is investigated from 1900 to 2020 deploying satellite and in situ datasets. As a part of this investigation, nearly 30 years of satellite altimetry data are used to compare with tide gauge data in terms of linear trend. This, in turn, leads to validation of the regional uplift model developed for the Fennoscandia. The role of North Atlantic Oscillation (NAO) in multidecadal variations of the Baltic Sea is also analyzed. Although NAO impacts the Baltic Sea level on seasonal to decadal time scales according to previous studies, it is not a pronounced factor in the multidecadal variations. The acceleration in the sea level rise of the basin is reported as statistically insignificant in recent studies or even decelerating in an investigation of the early 1990s. It is shown that the reason for these results relates to the global warming hiatus in the 1950s−1970s, which can be seen in all eight tide gauges used for this study. To account for the slowdown period, the acceleration in the basin is investigated by fitting linear trends to time spans of six to seven decades, which include the hiatus. These results imply that the sea level rise is accelerated in the Baltic Sea during the period 1900–2020.

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  • 6.
    Ahmed, Dolovan
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Fadul, Mohammed Erik Jamal
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Utsläpp från svenska reningsverk till Östersjön: Granskning av Henriksdals reningsverk, Ryaverket, Sjölunda reningsverk, Kungssängsverket och Duvbackens reningsverk2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    From domestic and industrial waste water will have to be cleaned before it can be released into lakes and streams again. This purification takes place through various stages of treatment plants. Wastewater contains many substances that are harmful to the environment as well as human and animal health, so it is important that the purification that is done is done in an efficient and thoughtful manner. The steps that are common in Swedish cleaning plants are mechanical, biological and chemical purification. These purification steps ensure that larger particles do not come out to the open water, convert nitrogen into nitrogen through the activation process, and that by chemical treatment, the emission of phosphorus is reduced. All of these purification steps can be designed differently and vary from purification plants to purification plants. Therefore, the degree of purification and emissions can distinguish between different treatment plants. Because there are many factors involved in the processes at Swedish waste treatment plants, it is important to carry out annual audits to detect problems that can lead to environmental damage.If cleaning does not work, exercise can increase in lakes and seas, which causes people and animals to suffer. Bottom dead and acid deficiency are already a major problem for the Baltic Sea. In order to reduce the negative environmental effects, emissions of nutrients are drastically reduced. This concerns the release of nutrients from all countries around the Baltic Sea.This study focuses on nitrogen and phosphorus purification from 5 wastewater treatment plants, Henriksdal's purification plant (Stockholm), Ryaverket (Gothenburg), Sjölunda purification plant (Malmö), Kungssängsverket (Uppsala) and Duvbacken purification plant (Gävle). Information about its activities has been obtained through interviews and works own reports.The purification plants use different technical solutions, and all treatment plants meet today's requirements for purification. The biggest difference is the degree of nitrogen purification. All wastewater treatment plants have a history of changes in technical solutions to improve treatment. Cleaning wastewater from households and industries costs a lot of money for the treatment plants, so it's always a challenge for the wastewater treatment plants to clean the water in the best possible way without costing too much.It is expected that the cleaning requirements will be tightened and all treatment plants should continue to develop to increase efficiency. Current purification requirements are designed to suit the recipient's sensitivity. If the EU's idea of ​​the same degree of purification across the country is transformed into requirements, Duvbacken will need to significantly improve the nitrogen treatment at the waste water treatment plant.

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  • 7.
    Alatalo, Juha M.
    et al.
    Qatar University.
    Jägerbrand, Annika
    Statens väg- och transportforskningsinstitut.
    Molau, Ulf
    Göteborgs Universitet.
    Impacts of different climate change regimes and extreme climatic events on an alpine meadow community2016In: Scientific Reports, E-ISSN 2045-2322, Vol. 6, article id 21720Article in journal (Refereed)
    Abstract [en]

    Climate variability is expected to increase in future but there exist very few experimental studies that apply different warming regimes on plant communities over several years. We studied an alpine meadow community under three warming regimes over three years. Treatments consisted of (a) a constant level of warming with open-top chambers (ca. 1.9 °C above ambient), (b) yearly stepwise increases in warming (increases of ca. 1.0, 1.9 and 3.5 °C), and (c) pulse warming, a single first-year pulse event of warming (increase of ca. 3.5 °C). Pulse warming and stepwise warming was hypothesised to cause distinct first-year and third-year effects, respectively. We found support for both hypotheses; however, the responses varied among measurement levels (whole community, canopy, bottom layer, and plant functional groups), treatments, and time. Our study revealed complex responses of the alpine plant community to the different experimentally imposed climate warming regimes. Plant cover, height and biomass frequently responded distinctly to the constant level of warming, the stepwise increase in warming and the extreme pulse-warming event. Notably, we found that stepwise warming had an accumulating effect on biomass, the responses to the different warming regimes varied among functional groups, and the short-term perturbations had negative effect on species richness and diversity.

  • 8.
    Alatalo, Juha M
    et al.
    Uppsala universitet, Växtekologi och evolution.
    Jägerbrand, Annika
    VTI, Swedish Natl Rd & Transport Res Inst, S-10215 Stockholm, Sweden..
    Molau, Ulf
    Univ Gothenburg, Dept Biol & Environm Sci, SE-40530 Gothenburg, Sweden..
    Testing reliability of short-term responses to predict longer-term responses of bryophytes and lichens to environmental change2015In: Ecological Indicators, ISSN 1470-160X, E-ISSN 1872-7034, Vol. 58, p. 77-85Article in journal (Refereed)
    Abstract [en]

    Environmental changes are predicted to have severe and rapid impacts on polar and alpine regions. At high latitudes/altitudes, cryptogams such as bryophytes and lichens are of great importance in terms of biomass, carbon/nutrient cycling, cover and ecosystem functioning. This seven-year factorial experiment examined the effects of fertilizing and experimental warming on bryophyte and lichen abundance in an alpine meadow and a heath community in subarctic Sweden. The aim was to determine whether shortterm responses (five years) are good predictors of longer-term responses (seven years). Fertilizing and warming had significant negative effects on total and relative abundance of bryophytes and lichens, with the largest and most rapid decline caused by fertilizing and combined fertilizing and warming. Bryophytes decreased most in the alpine meadow community, which was bryophyte-dominated, and lichens decreased most in the heath community, which was lichen-dominated. This was surprising, as the most diverse group in each community was expected to be most resistant to perturbation. Warming alone had a delayed negative impact. Of the 16 species included in statistical analyses, seven were significantly negatively affected. Overall, the impacts of simulated warming on bryophytes and lichens as a whole and on individual species differed in time and magnitude between treatments and plant communities (meadow and heath). This will likely cause changes in the dominance structures over time. These results underscore the importance of longer-term studies to improve the quality of data used in climate change models, as models based on short-term data are poor predictors of long-term responses of bryophytes and lichens.

  • 9.
    Alfredsson, Anders
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences. frastructure, Geodata Division, Lantmäteriet , Gävle , Sweden.
    Ågren, Jonas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences. Department of Geodetic Infrastructure, Geodata Division, Lantmäteriet , SE-80182 Gävle , Sweden.
    A first step towards a national realisation of the international height reference system in Sweden with a comparison to RH 20002023In: Journal of Geodetic Science, ISSN 2081-9919, E-ISSN 2081-9943, Vol. 13, no 1, article id 20220156Article in journal (Refereed)
    Abstract [en]

    The International Height Reference System (IHRS) was defined by the International Association of Geodesy in 2015. Since then, the international geodetic community has been working on the specification and establishment of its realisation, the International Height Reference Frame (IHRF). This frame will primarily be realised by geopotential numbers (or physical heights) in a sparse global reference network. In Sweden, only one such global station is planned. Regional and national realisations (or densifications) computed in accordance with the IHRS definition are needed to enable the best possible unification of height datums. The main purpose of this article is to make a case study for Sweden regarding the national realisation of IHRS and to investigate in what way preliminary IHRF differs from the current Swedish levelling-based realisation of the European Vertical Reference System, RH 2000. The two different quasigeoid models that we consider best over Sweden at the present time are used to compute the preliminary IHRS realisations in the study. The realisations are compared to each other and to RH 2000. It is shown that a very significant part of the difference to RH 2000 is due to the different postglacial land uplift epochs, permanent tide concepts, and zero levels. The standard deviation for the difference between one of the preliminary national IHRS realisations and RH 2000 is reduced from 75.5 to 19.2 mm after correction of the postglacial land uplift and permanent tide effects. The corresponding mean differences are –208.5 and –454.7 mm, respectively. The magnitude of the mean difference thus increases when the corrections in question are applied.

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  • 10.
    Alfredsson, Anders
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences. Department of Geodetic Infrastructure, Geodata Division, Lantmäteriet, Gävle, Sweden.
    Ågren, Jonas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences. Department of Geodetic Infrastructure, Geodata Division, Lantmäteriet, Gävle, Sweden.
    Olsson, Per-Anders
    Department of Geodetic Infrastructure, Geodata Division, Lantmäteriet, Gävle, Sweden.
    A Comparison of Pointwise and Levelling Assisted Regional Realisations of IHRS with a Case Study over Sweden2023In: International Association of Geodesy Symposia / [ed] Jeffrey T Freymueller, Springer Berlin/Heidelberg, 2023Chapter in book (Refereed)
    Abstract [en]

    The International Height Reference System (IHRS) was defined by the International Association of Geodesy (IAG) in 2015. The global International Height Reference Frame (IHRF) should provide access to the IHRS in a broad sense. To provide high accuracy local access, regional (or national) realisations will also be needed. This study aims at evaluating different approaches to compute a denser regional realisation of IHRS in case a high accuracy levelling network is available. Using Sweden as a case study region, a GNSS (Global Navigation Satellite System) and geoid based pointwise realisation is compared with three types of levelling assisted realisations. The latter are made by applying least squares adjustments of the precise levelling observations with fixed potential value(s) from either the global IHRF station in Sweden or the pointwise potentials of a larger number of stations. It is concluded that making a minimum constraint adjustment with one station fixed is not the best option. It is favourable to fix a reasonable number of pointwise stations at an internal distance over which the relative uncertainty of levelling is significantly lower than the relative uncertainty of the pointwise solution. The investigation is made using levelling data from the third precise levelling of Sweden, the NKG2015 quasigeoid model and the NKG2016LU postglacial land uplift model.

  • 11.
    Ali, Fadi
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Urban classification by pixel and object-based approaches for very high resolution imagery2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Recently, there is a tremendous amount of high resolution imagery that wasn’t available years ago, mainly because of the advancement of the technology in capturing such images. Most of the very high resolution (VHR) imagery comes in three bands only the red, green and blue (RGB), whereas, the importance of using such imagery in remote sensing studies has been only considered lately, despite that, there are no enough studies examining the usefulness of these imagery in urban applications. This research proposes a method to investigate high resolution imagery to analyse an urban area using UAV imagery for land use and land cover classification. Remote sensing imagery comes in various characteristics and format from different sources, most commonly from satellite and airborne platforms. Recently, unmanned aerial vehicles (UAVs) have become a very good potential source to collect geographic data with new unique properties, most important asset is the VHR of spatiotemporal data structure. UAV systems are as a promising technology that will advance not only remote sensing but GIScience as well. UAVs imagery has been gaining popularity in the last decade for various remote sensing and GIS applications in general, and particularly in image analysis and classification. One of the concerns of UAV imagery is finding an optimal approach to classify UAV imagery which is usually hard to define, because many variables are involved in the process such as the properties of the image source and purpose of the classification. The main objective of this research is evaluating land use / land cover (LULC) classification for urban areas, whereas the data of the study area consists of VHR imagery of RGB bands collected by a basic, off-shelf and simple UAV. LULC classification was conducted by pixel and object-based approaches, where supervised algorithms were used for both approaches to classify the image. In pixel-based image analysis, three different algorithms were used to create a final classified map, where one algorithm was used in the object-based image analysis. The study also tested the effectiveness of object-based approach instead of pixel-based in order to minimize the difficulty in classifying mixed pixels in VHR imagery, while identifying all possible classes in the scene and maintain the high accuracy. Both approaches were applied to a UAV image with three spectral bands (red, green and blue), in addition to a DEM layer that was added later to the image as ancillary data. Previous studies of comparing pixel-based and object-based classification approaches claims that object-based had produced better results of classes for VHR imagery. Meanwhile several trade-offs are being made when selecting a classification approach that varies from different perspectives and factors such as time cost, trial and error, and subjectivity.

          Classification based on pixels was approached in this study through supervised learning algorithms, where the classification process included all necessary steps such as selecting representative training samples and creating a spectral signature file. The process in object-based classification included segmenting the UAV’s imagery and creating class rules by using feature extraction. In addition, the incorporation of hue, saturation and intensity (IHS) colour domain and Principle Component Analysis (PCA) layers were tested to evaluate the ability of such method to produce better results of classes for simple UAVs imagery. These UAVs are usually equipped with only RGB colour sensors, where combining more derived colour bands such as IHS has been proven useful in prior studies for object-based image analysis (OBIA) of UAV’s imagery, however, incorporating the IHS domain and PCA layers in this research did not provide much better classes. For the pixel-based classification approach, it was found that Maximum Likelihood algorithm performs better for VHR of UAV imagery than the other two algorithms, the Minimum Distance and Mahalanobis Distance. The difference in the overall accuracy for all algorithms in the pixel-based approach was obvious, where the values for Maximum Likelihood, Minimum Distance and Mahalanobis Distance were respectively as 86%, 80% and 76%. The Average Precision (AP) measure was calculated to compare between the pixel and object-based approaches, the result was higher in the object-based approach when applied for the buildings class, the AP measure for object-based classification was 0.9621 and 0.9152 for pixel-based classification. The results revealed that pixel-based classification is still effective and can be applicable for UAV imagery, however, the object-based classification that was done by the Nearest Neighbour algorithm has produced more appealing classes with higher accuracy. Also, it was concluded that OBIA has more power for extracting geographic information and easier integration within the GIS, whereas the result of this research is estimated to be applicable for classifying UAV’s imagery used for LULC applications.

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  • 12. Allah Tavakoli, Yahya
    et al.
    Amin, Hadi
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Bagheri, Hamidreza
    Bagherbandi, Mohammad
    On an approach to surface mass change detection from satellite gravimetry, a case study of barystatic sea-level, ice-sheet mass and basin mass changes2022In: Article in journal (Refereed)
  • 13.
    Al-Sabti, Rita
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Fransson, Josefin
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Missfärgat dricksvatten i Sandvikens kommun: En studie med avseende på järn och mangan2021Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Drinking water is a cornerstone to a prosperous society. The quality of drinking water is affected by the type of raw-water sources and how drinking water treatment is carried out in a drinking water treatment plant. If the quality of the drinking water deteriorates, it may indicate that the drinking water treatment is not optimal or that the quality of raw-water sources has changed.The municipality of Sandviken in Sweden has had recurring problems with brown and black discolorations of the drinking water. Brown and black discolorations can be caused by oxidation of iron and manganese in the drinking water distribution system. The oxidation of manganese leads to the formation of manganese dioxide that can accelerate the corrosion processes of cast iron pipes. The Swedish Food Agency has set a limit value for the concentration of iron and manganese in drinking water to prevent the formation of precipitates in the drinking water distribution system. The aim of the study is to investigate whether the discolorations are due to high levels of iron and manganese in the drinking water. Water samples were collected to practically and statistically analyse the concentrations of iron, manganese and the formation of manganese dioxide. The statistical analysis showed that the levels of manganese were at their highest closest to the drinking water treatment plant. No other statistical correlations have been established. The analysis of manganese showed that 20 out of 31 water samples were above the limit value. The limit value for manganese was already exceeded at the drinking water treatment plant. The analysis of iron showed that 2 out of 24 water samples were above the limit value. Results also showed the presence of manganese-oxidizing microorganisms in the drinking water distribution system. Manganese is emitted from the drinking water plant and favors microorganisms as well as increases the formation of manganese dioxide, which may cause corrosion on cast iron pipes. Thus, the composition of the drinking water can affect or accelerate corrosion in the drinking water distribution system.Theoretically, the discolorations that have been experienced by the users may be due to a high concentration of manganese. However, it cannot be excluded that discolorations may be caused by other factors as the result did not provide a statistical relationship between discoloration and the concentration of iron and manganese. Further studies are required to determine all the causes behind discoloured drinking water. The problem of the concentrations of manganese should be solved, whether or not it is the main cause of the water discoloration. The concentrations of iron and manganese are likely to increase in the raw water due to climate change. If the drinking water plant continues to mix surface and groundwater, the problem can be solved by installing a static mixer and introducing a separation step for iron and manganese. When choosing a biological separation method, microorganisms from the drinking water distribution system can be used.

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    Missfärgat dricksvatten i Sandvikens kommun
  • 14.
    Amin, Hadi
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Study on the Earth’s Surface Mass Variations using Satellite Gravimetry Observations2022Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Our complex planet is continuously undergoing temporal and spatial changes. In this context, ongoing processes in the Earth subsystems (geosphere, biosphere, cryosphere, hydrosphere, and atmosphere) cause changes in the gravity field of the Earth across a wide range of temporal and spatial scales. Accordingly, by both spatially and temporally tracing our planet’s ever-changing gravity field, scientists can better constrain the underlying processes contributing to such dynamic changes of mass distribution within the Earth system. Monitoring the Earth’s gravity field and its temporal variations is essential, among others, for tracking disasters and specifying land areas with a high risk of flooding, earthquakes, and droughts, movements of tectonic plates, and providing accurate positioning through satellite positioning technology. On short-term timescales, temporal variations in the Earth’s gravity field are mainly caused by the movement of water in its various forms. Accordingly, sea-level variations and ice-sheet and glacier changes, which are known as critical indicators of global warming and climate change, can be accurately monitored by tracking the Earth’s gravity field changes. Since there is a close link between water redistribution and the Earth’s energy cycle, climate system, food security, human and ecosystem health, energy generation, economic and societal development, and climate extremes (droughts and floods), it is essential to accurately monitor water mass exchange between the Earth system components. Among all observational techniques, satellite gravimetry has provided an integrated global view of ongoing processes within the Earth system. The current generation of satellite gravimetry missions (the Gravity Recovery and Climate Experiment (GRACE) mission and its successor, GRACE Follow-On) has dramatically revolutionized our understanding of dynamic processes in the Earth’s surface and, consequently, has significantly improved our understanding of the Earth’s climate system. By considering different aspects of studying the Earth’s gravity field, this thesis brings new insights to the determination and analysis of the mass change in the Earth system. First, by studying the shortcomings of the common techniques of estimating the geoid potential, a new approach is examined that simultaneously estimates the geoid potential, W0, and the geometrical parameters of the reference Mean Earth Ellipsoid (MEE). In this regard, as the geoid needs to be considered as a static equipotential surface, the sensitivity of the estimations to the time dependent Earth’s gravity field changes is studied. Secondly, relying on the GRACE monthly gravity fields and the complementary observational techniques, and by pushing the limit of GRACE, mass redistribution over land and ocean is investigated. Within the ocean, satellite altimetry and Argo products are utilized along with the GRACE monthly solutions for quantifying the global barystatic sea-level change and assessing the closure of the global mean sea level budget. Over land, a region with relatively high temporal mass change (oil and water extraction) is chosen in which by taking advantage of having in-situ observations and hydrological models, the ability of GRACE products in quantifying the changes in groundwater storage is studied. In this frame, for both the ocean and land studies, different aspects of the processing of GRACE monthly gravity fields are investigated and GRACE inherent errors are addressed appropriately to arrive at reliable and accurate estimates of the Earth’s surface mass change. As the final contribution in this thesis, a rigorous analytical model for detecting surface mass change from the time-variable gravity solutions is proposed and examined in different case studies of surface mass change. Since the launch of the GRACE twin satellites, the GRACE(-FO) time-varying gravity fields are conventionally converted into the surface mass change using a spherical analytical model that approximates the Earth by a sphere. More recently, the analytical mass change detection model has been improved by considering an ellipsoid as the shape of the Earth, which improved the previous estimations of surface mass change, especially over high latitudes with relatively large mass change signals. However, by taking into account the real shape of the Earth and considering more realistic assumptions, a new analytical solution for the problem of surface mass change detection from the time-varying gravity fields is proposed in this thesis. It is shown that the simplistic spherical and ellipsoidal geometries are no longer tenable and the new model surpasses the common spherical approach and its ellipsoidal version.

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  • 15.
    Amin, Hadi
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Sjöberg, Lars E.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Evaluation of the Closure of Global Mean Sea Level Rise Budget over January 2005 to August 20162019Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    Sea level changes over time because of water mass exchange among the oceans and continents, ice sheets, and atmosphere. It fluctuates also due to variations of seawater salinity and temperature known as the steric contributor. GRACE-based Stokes coefficients provide a valuable source of information, about the water mass exchange as the main contributor to the Earth’s gravity field changes, within decadal scales. Moreover, measuring seawater temperature and salinity at different layers of ocean depth, Argo floats help to model the steric component of Global Mean Sea Level. In this study, we evaluate the Global Mean Sea Level (GMSL) budget closure using satellite altimetry, GRACE, and Argo products. Hereof, considering the most recent released GRACE monthly products (RL06), we examine an iterative remove-restore method to minimize the effect of artifact leaked large signal from ice sheets and land hydrology. In addition, the effect of errors and biases in geophysical model corrections, such as GIA, on the GMSL budget closure is estimated. Moreover, we quantify the influence of spatial and decorrelation filtering of GRACE data on the GMSL budget closure. In terms of the monthly fluctuations of sea level, our results confirm that closing the GMSL budget is highly dependent on the choice of the spatial averaging filter. In addition, comparing the trends and variations for both the global mean sea level time series and those estimated for mass and steric components, we find that spatial averaging functions play a significant role in the sea level budget closure.

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  • 16.
    Amin, Hadi
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences. KTH.
    Sjöberg, Lars E.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences. KTH.
    Quantifying barystatic sea-level change from satellite altimetry, GRACE and Argo observations over 2005–20162020In: Advances in Space Research, ISSN 0273-1177, E-ISSN 1879-1948, Vol. 65, no 8, p. 1922-1940Article in journal (Refereed)
    Abstract [en]

    Time-varying spherical harmonic coefficients determined from the Gravity Recovery and Climate Experiment (GRACE) data provide a valuable source of information about the water mass exchange that is the main contributor to the Earth’s gravity field changes within a period of less than several hundred years. Moreover, by measuring seawater temperature and salinity at different layers of ocean depth, Argo floats help to measure the steric component of global mean sea level (GMSL). In this study, we quantify the rate of barystatic sea-level change using both GRACE RL05 and RL06 monthly gravity field models and compare the results with estimates achieved from a GMSL budget closure approach. Our satellite altimetry-based results show a trend of 3.90 ± 0.14 mm yr−1 for the GMSL rise. About 35% or 1.29 ± 0.07 mm yr−1 of this rate is caused by the thermosteric contribution, while the remainder is mainly due to the barystatic contribution. Our results confirm that the choice of decorrelation filters does not play a significant role in quantifying the global barystatic sea-level change, and spatial filtering may not be needed. GRACE RL05 and RL06 solutions result in the barystatic sea-level change trends of 2.19 ± 0.13 mm yr−1 and 2.25 ± 0.16 mm yr−1, respectively. Accordingly, the residual trend, defined as the difference between the altimetry-derived GMSL and sum of the steric and barystatic components, amounts to 0.51 ± 0.51 and 0.45 ± 0.44 mm yr−1 for RL05 and RL06-based barystatic sea-level changes, respectively, over January 2005 to December 2016. The exclusion of the halosteric component results in a lower residual trend of about 0.36 ± 0.46 mm yr−1 over the same period, which suggests a sea-level budget closed within the uncertainty. This could be a confirmation on a high level of salinity bias particularly after about 2015. Moreover, considering the assumption that the GRACE-based barystatic component includes all mass change signals, the rather large residual trend could be attributed to an additional contribution from the deep ocean, where salinity and temperature cannot be monitored by the current observing systems. The errors from various sources, including the model-based Glacial Isostatic Adjustment signal, independent estimation of geocenter motion that are not quantified in the GRACE solutions, as well as the uncertainty of the second degree of zonal spherical harmonic coefficients, are other possible contributors to the residual trend.

  • 17.
    Amin, Hadi
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Sjöberg, Lars
    Division of Geodesy and satellite positioning, KTH.
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    A global vertical datum defined by the conventional geoid potential and the Earth ellipsoid parameters2019In: Journal of Geodesy, ISSN 0949-7714, E-ISSN 1432-1394, Vol. 93, no 10, p. 1943-1961Article in journal (Refereed)
    Abstract [en]

    The geoid, according to the classical Gauss–Listing definition, is, among infinite equipotential surfaces of the Earth’s gravity field, the equipotential surface that in a least squares sense best fits the undisturbed mean sea level. This equipotential surface, except for its zero-degree harmonic, can be characterized using the Earth’s global gravity models (GGM). Although, nowadays, satellite altimetry technique provides the absolute geoid height over oceans that can be used to calibrate the unknown zero-degree harmonic of the gravimetric geoid models, this technique cannot be utilized to estimate the geometric parameters of the mean Earth ellipsoid (MEE). The main objective of this study is to perform a joint estimation of W0, which defines the zero datum of vertical coordinates, and the MEE parameters relying on a new approach and on the newest gravity field, mean sea surface and mean dynamic topography models. As our approach utilizes both satellite altimetry observations and a GGM model, we consider different aspects of the input data to evaluate the sensitivity of our estimations to the input data. Unlike previous studies, our results show that it is not sufficient to use only the satellite-component of a quasi-stationary GGM to estimate W0. In addition, our results confirm a high sensitivity of the applied approach to the altimetry-based geoid heights, i.e., mean sea surface and mean dynamic topography models. Moreover, as W0 should be considered a quasi-stationary parameter, we quantify the effect of time-dependent Earth’s gravity field changes as well as the time-dependent sea level changes on the estimation of W0. Our computations resulted in the geoid potential W0 = 62636848.102 ± 0.004 m2 s−2 and the semi-major and minor axes of the MEE, a = 6378137.678 ± 0.0003 m and b = 6356752.964 ± 0.0005 m, which are 0.678 and 0.650 m larger than those axes of GRS80 reference ellipsoid, respectively. Moreover, a new estimation for the geocentric gravitational constant was obtained as GM = (398600460.55 ± 0.03) × 106 m3 s−2.

  • 18.
    Amin, Hadi
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Sjöberg, Lars E.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    A global vertical datum defined by the conventional geoid potential and the Earth ellipsoid parameters2020Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    According to the classical Gauss–Listing definition, the geoid is the equipotential surface of the Earth’s gravity field that in a least-squares sense best fits the undisturbed mean sea level. This equipotential surface, except for its zero-degree harmonic, can be characterized using the Earth’s Global Gravity Models (GGM). Although nowadays, the satellite altimetry technique provides the absolute geoid height over oceans that can be used to calibrate the unknown zero-degree harmonic of the gravimetric geoid models, this technique cannot be utilized to estimate the geometric parameters of the Mean Earth Ellipsoid (MEE). In this study, we perform joint estimation of W0, which defines the zero datum of vertical coordinates, and the MEE parameters relying on a new approach and on the newest gravity field, mean sea surface, and mean dynamic topography models. As our approach utilizes both satellite altimetry observations and a GGM model, we consider different aspects of the input data to evaluate the sensitivity of our estimations to the input data. Unlike previous studies, our results show that it is not sufficient to use only the satellite componentof a quasi-stationary GGM to estimate W0. In addition, our results confirm a high sensitivity of the applied approach to the altimetry-based geoid heights, i.e. mean sea surface and mean dynamic topography models. Moreover, as W0 should be considered a quasi-stationary parameter, we quantify the effect of time-dependent Earth’s gravity field changes as well as the time-dependent sea-level changes on the estimation of W0. Our computations resulted in the geoid potential W0 = 62636848.102 ± 0.004 m2s-2 and the semi-major and –minor axes of the MEE,a = 6378137.678 ± 0.0003 m and b = 6356752.964 ± 0.0005 m, which are 0.678 and 0.650 m larger than those axes of the GRS80 reference ellipsoid, respectively. Moreover, a new estimation for the geocentric gravitational constant was obtained as GM = (398600460.55 ± 0.03) × 106 m3s-2.

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  • 19.
    Andersson, Erik
    et al.
    Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden; Beijer Institute, Royal Swedish Academy of Sciences, Stockholm, Sweden.
    Barthel, Stephan
    Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden.
    Borgström, Sara
    Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden.
    Colding, Johan
    Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden; The Beijer Institute, Royal Swedish Academy of Sciences, Stockholm, Sweden.
    Elmqvist, Thomas
    Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden.
    Folke, Carl
    Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden; The Beijer Institute, Royal Swedish Academy of Sciences, Stockholm, Sweden.
    Gren, Åsa
    The Beijer Institute, Royal Swedish Academy of Sciences, Stockholm, Sweden.
    Reconnecting Cities to the Biosphere: Stewardship of Green Infrastructure and Urban Ecosystem Services2014In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 43, no 4, p. 445-453Article in journal (Refereed)
    Abstract [en]

    Within-city green infrastructure can offer opportunities and new contexts for people to become stewards of ecosystem services. We analyze cities as social-ecological systems, synthesize the literature, and provide examples from more than 15 years of research in the Stockholm urban region, Sweden. The social-ecological approach spans from investigating ecosystem properties to the social frameworks and personal values that drive and shape human interactions with nature. Key findings demonstrate that urban ecosystem services are generated by social-ecological systems and that local stewards are critically important. However, land-use planning and management seldom account for their role in the generation of urban ecosystem services. While the small scale patchwork of land uses in cities stimulates intense interactions across borders much focus is still on individual patches. The results highlight the importance and complexity of stewardship of urban biodiversity and ecosystem services and of the planning and governance of urban green infrastructure.

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  • 20.
    Andersson, Erik
    et al.
    Stockholms universitet, Stockholm Resilience Centre.
    Colding, Johan
    Stockholms universitet, Stockholm Resilience Centre.
    Understanding how built urban form influences biodiversity2014In: Urban Forestry & Urban Greening, ISSN 1618-8667, E-ISSN 1610-8167, Vol. 13, no 2, p. 221-226Article in journal (Refereed)
    Abstract [en]

    This study seeks to contribute to a more complete understanding of how urban form influences biodiversity by investigating the effects of green area distribution and that of built form. We investigated breeding bird diversity in three types of housing development with approximately the same amount of tree cover. No significant differences in terms of bird communities were found between housing types in any of the survey periods. However, detached housing, especially with interspersed trees, had more neotropical insectivores and higher overall diversity of insectivores. Based on our results and theory we suggest a complementary approach to managing biodiversity in urban landscapes - instead of maximising the value and quality of individual patches efforts could go into enhancing over-all landscape quality at the neighbourhood scale by splitting up part of the green infrastructure. The relatively small differences in bird communities also suggest that different stakeholder groups may be engaged in management.

  • 21.
    Andersson, Erik
    et al.
    Stockholm Resilience Centre, Stockholm University; North-West University, Potchefstroom, South Africa.
    Grimm, Nancy B
    Arizona State University, Tempe, AZ, USA.
    Lewis, Joshua A
    Tulane University, New Orleans, LA, USA.
    Redman, Charles L
    Arizona State University, Tempe, AZ, USA.
    Barthel, Stephan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science. Stockholm Resilience Centre, Stockholm University.
    Colding, Johan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science. The Beijer Institute of Ecological Economics, Royal Swedish Academy of Sciences, Stockholm.
    Elmqvist, Thomas
    Urban climate resilience through hybrid infrastructure2022In: Current Opinion in Environmental Sustainability, ISSN 1877-3435, E-ISSN 1877-3443, Vol. 55, article id 101158Article in journal (Refereed)
    Abstract [en]

    Urban infrastructure will require transformative changes to adapt to changing disturbance patterns. We ask what new opportunities hybrid infrastructure—built environments coupled with landscape-scale biophysical structures and processes—offer for building different layers of resilience critical for dealing with increased variation in the frequency, magnitude and different phases of climate-related disturbances. With its more diverse components and different internal logics, hybrid infrastructure opens up alternative and additive ways of building resilience for and through critical infrastructure, by providing a wider range of functions and responses. Second, hybrid infrastructure points toward greater opportunities for ongoing (re)design at the landscape level, where structure and function can be constantly renegotiated and recombined.

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  • 22.
    Andersson, Hanna
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Decision, Risk and Policy Analysis.
    Ahonen-Jonnarth, Ulla
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Decision, Risk and Policy Analysis.
    Holmgren, Mattias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science.
    Marsh, John E.
    University of Central Lancashire, UK; Luleå University of Technology.
    Wallhagen, Marita
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science.
    Bökman, Fredrik
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Decision, Risk and Policy Analysis.
    What influences people’s tradeoff decisions between CO2 emissions and travel time? An experiment with anchors and normative messages2021In: Frontiers in Psychology, E-ISSN 1664-1078, Vol. 12, article id 702398Article in journal (Refereed)
    Abstract [en]

    One of the today’s greatest challenges is to adjust our behavior so that we can avoid a major climate disaster. To do so, we must make sacrifices for the sake of the environment. The study reported here investigates how anchors (extrinsic motivational-free information) and normative messages (extrinsic motivational information) influence people’s tradeoffs between travel time and carbon dioxide (CO2) emissions in the context of car travel and whether any interactions with environmental concern (an intrinsic motivational factor) can be observed. In this study, people received either a CO2, health or no normative message together with either a high anchor, a low anchor, or no anchor. People that received both a high anchor and a CO2 emission normative message were willing to travel for a longer time than those that only received a high anchor. If a low anchor was presented, no differences in willingness to travel for a longer time were found between the three different conditions of normative message groups, i.e., CO2 normative message, health normative message, or no normative message. People with higher concern for the environment were found to be willing to travel for a longer time than those with lower concern for the environment. Further, this effect was strongest when a high anchor was presented. These results suggest that anchors and normative messages are among the many factors that can influence people’s tradeoffs between CO2 emission and travel time, and that various factors may have to be combined to increase their influence over pro-environmental behavior and decisions.

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  • 23.
    Andersson, Kjell
    et al.
    School for Forest Management, Faculty of Forest Sciences, Swedish University of Agriculture.
    Angelstam, Per
    School for Forest Management, Faculty of Forest Sciences, Swedish University of Agriculture / Department of Forestry and Wildlife Management, Inland Norway University of Applied Sciences.
    Brandt, S. Anders
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Axelsson, Robert
    County Administrative Board Västmanland.
    Bax, Gerhard
    Limited GIS skills hamper spatial planning for green infrastructures in Sweden2022In: Geografiska Notiser, ISSN 0016-724X, Vol. 80, no 1, p. 16-35Article in journal (Other academic)
    Abstract [en]

    The term green infrastructure captures the need to conserve biodiversity and to sustain landscapes’ different ecosystem services. Maintaining green infrastructures through protected areas, management and landscape restoration requires knowledge in geography, spatial data about biophysical, anthropogenic and immaterial values, spatial comprehensive planning, and thus geographical information systems (GIS). To understand land use planning practices and planning education regarding GIS in Sweden we interviewed 43 planners and reviewed 20 planning education programmes. All planners used GIS to look at data but did not carry out spatial analyses of land covers. BSc programmes included more GIS than MSc programmes but very few taught analyses for spatial planning. As key spatial planning actors, municipalities’ barriers and bridges for improved GIS use for collaborative learning about green infrastructures are discussed. A concluding section presents examples of how GIS can support spatial planning for green infrastructures.

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  • 24.
    Andersson, Victor
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Mikroplastens uppkomst och spridning: En fallstudie förlagd till Hudiksvalls kommun2020Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Plastic and microplastics in nature, sea and water are a major global problem. Because plastics in different forms are present in a big variety of products, this leads to a big volume of plastics that can be spread out to nature from different emission sources. Plastics do not have a sure degradation time; plastics can, therefore, affect the environment for a very long time due to the formation of degraded plastics microplastics over time. Microplastics can also be manufactured as such, in the form of, for example rubber granules. This thesis is a literature study of microplastics in the municipality of Hudiksvall, with a delimitation of four of the following major emission sources of microplastics, artificial turf, littering, washing of synthetic fibres textiles and wire tear and road marking paint. The rapport is also showing the approximate quantity of the emissions from the sources above in the municipality of Hudiksvall together with proposed actions with a proposed priority order. The results show the emissions within the municipality to be relatively large, however, it is possible to greatly reduce some of the emissions with relatively simple and cost-effective means. The emissions from artificial turf can be greatly reduced with the following actions. Shoe brushes near the artificial grass, granular traps in the nearby stormwater drains for collection of rubber granular that otherwise would have ended up in the stormwater. The third action is a barrier at the sides of the artificial turf to prevent the spreading of rubber granular to nearby areas. More studies are needed regarding the emissions from littering, wire tear and road marking paints and washing of synthetic textiles to find more secure local and regional data and to get more data of what happens to the microplastics after it leaves the roads. The emissions of microplastics from artificial turfs can physically be addressed while the other three emission sources require both more information and changed habits and patterns to give a bigger impact to the measures.  Some examples may be to reduce the use of trucks for heavy transport and use trains to a greater extent. Another is to increase the use of public transport to reduce the use of cars. The municipality of Hudiksvall intends to follow Agenda 2 030, which is several global goals for economic, social, and ecological sustainability. In Sweden and Hudiksvall the environmental goals have been even more specified to clarify the most important measures. Hudiksvall municipality is an eco-municipality since 2 002. That means all decisions must be included in the sustainability principle, new ways of thinking are seen as important. Future studies of microplastics and its emission pathways are required to get more specific local data to be able to work actively to reduce the emissions regardless of the size or source.

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  • 25.
    Ardavan, Mehdi
    University of Gävle, Department of Technology and Built Environment.
    Metamaterial: A field magnitude dependent and frequency independent model2008Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    In all attempts to analyze and realize Left-Handed materials, so far, most researchers have used the same idea of extracting only some or certain behaviors of Metamaterials from a set of unit cells gathered together in a designed order. Nevertheless meeting all criteria in order to consider a media as real double-negative material has never come true.

    Starting with criticizing and arguing the validity of calling any set of unit cells as a medium of propagation, the work at hand will go further demonstrating analogies between a medium which could be assigned permittivity or permeability factors and the medium consisting a set of unit cells.

    After presenting the critical analysis on previous studies in the field, here it is shown that it is impossible to build Metamaterials using any number of passive unit cells. A deep insight into the concept of phase and group velocities as well as Poynting’s vector will reveal weakness of the public perception of their relation with each other. Unlike the past and current trend in analyzing these two velocities in meta-materials, they will be proven to possess the same direction.

    Moreover, in this work, a solid proof over violation of energy conservation in the intersection plane between a normal material and a Left Handed material is presented which requires us to believe and accept generation of energy at this plane. This view will consequently leave meaningless all attempts to build meta-materials by passive elements.

    In present work a method is proposed at which a material with positive permittivity and permeability can behave like and yield all characteristics of Metamaterials only if the foregoing parameters, while remaining positive, can vary and be governed by the magnitude of the electromagnetic field. Independence of this method from frequency broadens the range of its application and also the interest it may attract.

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  • 26.
    Arnström, Sebastian
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science.
    Of Chaos And Clockworks: A Formal Criticism Of The Modern Sustainability Paradigm2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis is a critical review of two central theories in the modern sustainability paradigm – namely… (1) the theory that the Earth’s geosphere, hydrosphere, biosphere and atmosphere form a complex adaptive system – the Earth system, and (2) the theory that all human activities are intrinsically dependent on, and constrained by, non-anthropogenic states and processes in the Earth system. The thesis explains the origins and the logic of these theories, and subjects them to formal, semi-formal and comparative criticism. Ultimately, it refutes both on formal and comparative grounds. Most importantly, it shows that theories 1 and 2 are in conflict with the theory of evolution by natural selection, and with the hypothetico-deductive model of scientific research. It also shows that they are in conflict – both directly and indirectly – with the known laws of physics. While it is true that all human activities rely on biospheric resources today, there are no physical, or natural laws that make it impossible for us to break those dependencies over time. In fact, the thesis shows that it is possible in principle to satisfy any human need by strictly artificial means, and abiotic resources that exist in abundance both inside and outside of the Earth system. An important corollary to this finding is that social and economic progress is not inextricably tied – as the modern sustainability literature suggests – to the exploitation of finite and rapidly diminishing resources here on Earth. Theories 1 and 2 both contribute to this confusion, and hence, to the bleak and irrational Malthusianism that still permeates so much of the sustainability domain. In addition, they appear to blind many researchers to the ecological benefits of technological development. That humanity can break its dependence on the biosphere is a very good thing for its non-human inhabitants. As we become more technologically advanced, we will find it easier and easier to sustain ourselves without destabilizing the world's ecosystems. The Earth’s biosphere is an oasis of beauty, complexity and connection in a Universe that is overwhelmingly empty and boring. As the only animals capable of appreciating this fact, we have a clear moral duty to protect and preserve it. And we can protect and preserve it. If we just let go of the religious ideas that have dominated our field since its inception, we will find that our potential to do good in the world is far greater than we previously imagined.

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  • 27.
    Arvidsson, Anna K
    et al.
    Statens väg- och transportforskningsinstitut, Drift och underhåll, DOU.
    Blomqvist, Göran
    Statens väg- och transportforskningsinstitut, Miljö, MILJÖ.
    Erlingsson, Sigurdur
    Statens väg- och transportforskningsinstitut, Väg- och banteknik, VBA.
    Hellman, Fredrik
    Statens väg- och transportforskningsinstitut, Väg- och banteknik, VBA.
    Jägerbrand, Annika
    Statens väg- och transportforskningsinstitut.
    Öberg, Gudrun
    Statens väg- och transportforskningsinstitut, Drift och underhåll, DOU.
    Klimatanpassning av vägkonstruktion, drift och underhåll2012Report (Other academic)
    Abstract [en]

    The global climate change is a reality and affecting society and transport systems. Climate change adaptation of transport systems will make the means of transportation more resilient and decrease the risk and magnitude of disruptions. Generally, climate change adaptations in road construction, operation and maintenance will need relatively large changes, but there is a shortage of the specific knowledge required as to what steps need to be taken, when and where, before measures can actually be implemented. Since climate change effects vary among Sweden's climatic zones, the impact of climate change on the road behavior and longevity is extremely difficult to predict. The need for winter maintenance in Sweden will generally decrease due to the warmer climate. Ploughing frequency will probably decrease as well, but preparedness should not be reduced too much since occasions with more extreme instances will increase. In order to succeed in making the road transport system resilient to climate change, we conclude that there is a need to develop more knowledge about the impact on the road infrastructure system as well as the operation and maintenance of the system including how to adapt through different types of variable and flexible climate adaptation measures and the effects of extreme weather events.

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  • 28.
    Arvidsson, Niklas
    et al.
    RISE.
    Bolin, Lisa
    RISE.
    Lindberg, Siv M
    RISE.
    Linder, Marcus
    RISE.
    Mellquist, Ann-Charlotte
    RISE.
    Norefjell, Fredric
    RISE.
    Nyström, Thomas
    RISE.
    Rex, Emma
    RISE.
    Norrblom, Hans-Lennart
    RISE.
    Tööj, Lars
    Industrial Development Center, Sweden..
    Cirkulära möbelflöden: Hur nya affärsmodeller kan bidra till hållbar utveckling inom offentliga möbler2017Report (Other academic)
    Abstract [en]

    Sverige har en stark möbelindustri och en stolt tradition av att tillverka tidlösa och högkvalitativa möbler, ofta av naturmaterial. 2016 producerade Sverige möbler för 22,8 miljarder SEK, varav kontorsmöbler stod för nästan en fjärdedel1. Det saknas idag statistik över vad som händer med dessa möbler när de inte längre används, men det står klart att många av dem slängs i förtid när verksamheter flyttar eller när deras behov ändras. Samtidigt syns en tydlig utveckling mot att kunder mer och mer efterfrågar återbrukade eller renoverade möbler som en del i sitt hållbarhetsarbete. Denna utveckling var startpunkten för projektet ”Affärsmodell-innovation för cirkulära möbelflöden”. Affärsmodellinnovation för cirkulära möbelflöden är ett Vinnovafinansierat projekt som under åren 2015-2017 arbetat med att utveckla och testa koncept för cirkulära affärsmodeller för i första hand offentliga möbler. I projektet har tjugo aktörer från hela värdekedjan, från underleverantörer, möbelproducenter, återförsäljare och användare till forskare och branschorgan, samarbetat kring affärsutveckling, kundincitament, produktdesign, logistik, hållbarhets- och certifieringsfrågor. Den här skriften belyser hur nya affärsmodeller för mer cirkulära möbelflöden kan bidra till en mer hållbar utveckling och ger smakprov på slutsatser från projektet. Skriften riktar sig framför allt till producenter och återförsäljare av möbler för offentliga miljöer, men även kunder och inköpare tror vi kan ha stor nytta av skriften. Vi hoppas att den även kan fungera som inspiration för andra industrier och branscher som funderar på en övergång till mer cirkulära affärsekosystem.

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  • 29.
    Aslani, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Computer Science.
    Computational and spatial analyses of rooftops for urban solar energy planning2022Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In cities where land availability is limited, rooftop photovoltaic panels (RPVs) offer high potential for satisfying concentrated urban energy demand by using only rooftop areas. However, accurate estimation of RPVs potential in relation to their spatial distribution is indispensable for successful energy planning. Classification, plane segmentation, and spatial analysis are three important aspects in this context. Classification enables extracting rooftops and allows for estimating solar energy potential based on existing training samples. Plane segmentation helps to characterize rooftops by extracting their planar patches. Additionally, spatial analyses enable the identification of rooftop utilizable areas for placing RPVs. This dissertation aims to address some issues associated with these three aspects, particularly (a) training support vector machines (SVMs) in large datasets, (b) plane segmentation of rooftops, and (c) identification of utilizable areas for RPVs. SVMs are among the most potent classifiers and have a solid theoretical foundation. However, they have high time complexity in their training phase, making them inapplicable in large datasets. Two new instance selection methods were proposed to accelerate the training phase of SVMs. The methods are based on locality-sensitive hashing and are capable of handling large datasets. As an application, they were incorporated into a rooftop extraction procedure, followed by plane segmentation. Plane segmentation of rooftops for the purpose of solar energy potential estimation should have a low risk of overlooking superstructures, which play an essential role in the placement of RPVs. Two new methods for plane segmentation in high-resolution digital surface models were thus developed. They have an acceptable level of accuracy and can successfully extract planar segments by considering superstructures. Not all areas of planar segments are utilizable for mounting RPVs, and some factors may further limit their useability. Two spatial methods for identifying RPV-utilizable areas were developed in this realm. They scrutinize extracted planar segments by considering panel installation regulations, solar irradiation, roof geometry, and occlusion, which are necessary for a realistic assessment of RPVs potential. All six proposed methods in this thesis were thoroughly evaluated, and the experimental results show that they can successfully achieve the objectives for which they were designed.

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  • 30.
    Aslani, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Computer Science.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Computer Science. Uppsala universitet.
    A Spatially Detailed Approach to the Assessment of Rooftop Solar Energy Potential based on LiDAR Data2022In: Proceedings of the 8th International Conference on Geographical Information Systems Theory, Applications and Management - GISTAM, ScitePress , 2022, p. 56-63Conference paper (Refereed)
    Abstract [en]

    Rooftop solar energy has long been regarded as a promising solution to cities’ growing energy demand and environmental problems. A reliable estimate of rooftop solar energy facilitates the deployment of photovoltaics and helps formulate renewable-related policies. This reliable estimate underpins the necessity of accurately pinpointing the areas utilizable for mounting photovoltaics. The size, shape, and superstructures of rooftops as well as shadow effects are the important factors that have a considerable impact on utilizable areas. In this study, the utilizable areas and solar energy potential of rooftops are estimated by considering the mentioned factors using a three-step methodology. The first step involves training PointNet++, a deep network for object detection in point clouds, to recognize rooftops in LiDAR data. Second, planar segments of rooftops are extracted using clustering. Finally, areas that receive sufficient solar irradiation, have an appropriate size, and fulfill photovoltaic installation requirements are identified using morphological operations and predefined thresholds. The obtained results show high accuracy for rooftop extraction (93%) and plane segmentation (99%). Moreover, the spatially detailed analysis indicates that 17% of rooftop areas are usable for photovoltaics.

  • 31.
    Ayoubi, Hilal
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Management, Industrial Design and Mechanical Engineering, Industrial Management.
    Maher Ali, Ali
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Management, Industrial Design and Mechanical Engineering, Industrial Management.
    Förståelsen om FN:s globala hållbarhetsmål: Hur arbetar småföretag med FN:s globala hållbarhetsmål2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The biggest challenge of the time today is climate change and its negative effects. One reason for many cases of political inequality, health risks and human rights inequalities is consumption and production patterns that lead to environmental degradation and injustice. Statistics from the Swedish Agency for Growth (2020) have shown that almost half of Swedish industry works with sustainable work. On the other hand, however, it is important to observe that the work towards sustainable development has expanded and become increasingly complicated to meet the latest conditions. 

    The purpose of this study is to investigate how highly the smaller companies value the UN's Global Sustainability Goals 12.4 in two different industries, and how they actively work to improve that work. The purpose has been fulfilled by the authors conducting interviews with two case companies, thus the authors have conducted a literature study in areas considered relevant. The study identified two key factors, the first key factor being that Gästrike Ekogas does not work on the basis of the global goals and therefore does not have values. In order to improve the work in sustainability, it has also been demonstrated that the business lacks resources. The other key factor identified by the authors is that St:Erik's vision is that they should be the obvious choice in sustainable community building, which indicates a lot that they have a serious value about sustainability. They also have the environment as a focus area, and which they work with constantly. As the business takes into account the chemical emissions and its consequences, and that St:Eriks also works constantly to reduce these emissions with the help of resources that exist within the business and with the help of third parties. 

    It has also been demonstrated that the activities in question should have the capability to combine new technologies, changes to practices, with new business models. In order for businesses to fortunately adopt and implement sustainable consumption and production, it is basically about demanding change in the organization's vision and education. Since St:Erik's products have a long lifespan, it was very important for them to relate to the UN's 12th global goals as it includes production and consumption.

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  • 32.
    Aytac, Selenay
    et al.
    Long Island University, NY, USA.
    Bautista-Puig, Núria
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Management, Industrial Design and Mechanical Engineering, Industrial Management. University of Gävle, Center for Logistics and Innovative Production. Complutense University of Madrid, Madrid, Spain.
    Orduña-Malea, Enrique
    Universitat Politècnica de València, Valencia, Spain.
    Tran, Clara Y.
    Stony Brook University, NY, USA.
    Contribution of carbon footprint research towards the triple bottom line of sustainability2023In: Environmental Science and Pollution Research, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 30, p. 88331-88349Article in journal (Refereed)
    Abstract [en]

    Carbon footprint (CF) research has received increasing attention in recent years, as evidenced by a rise in publications and citations, reflecting a growing concern for the environmental impact of human activities. However, the alignment of this scientific literature with the three dimensions of sustainability performance provided by the TBL paradigm (people, planet, and profit) has received limited attention. This study addresses this research gap by undertaking a large-scale bibliometric analysis of 9032 Web of Science (WoS) publications from 1992 to 2020. At the macro (journals) and micro (papers) levels, a methodology approach to classify research publications according to TBL dimensions was designed. The results indicate that the output and impact of CF research are balanced with respect to the environmental (planet) and economic (prosperity/profit) dimensions, while the social impact is balanced with respect to the people+profit dimensions. Other than that, “Affordable and Clean Energy” (3761 publications) and “Climate Action” (3091 publications) are the most frequently represented (and interconnected) objectives. The results obtained contribute to a greater understanding of the contribution of CF research to the attainment of the SDGs.

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  • 33.
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    A study on the quality of GNSS signals for extracting the sea level height and tidal frequencies utilizing the GNSS-R approach2023Conference paper (Other (popular science, discussion, etc.))
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  • 34.
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute.
    Combination of seismic and an isostatic crustal thickness models using Butterworth filter in a spectral approach2012In: Journal of Asian Earth Sciences, ISSN 1367-9120, E-ISSN 1878-5786, Vol. 59, p. 240-248Article in journal (Refereed)
  • 35.
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS. Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), Stockholm, Sweden .
    Deformation monitoring using different least squares adjustment methods: a simulated study2016In: KSCE Journal of Civil Engineering, ISSN 1226-7988, E-ISSN 1976-3808, Vol. 20, no 2, p. 855-862Article in journal (Refereed)
    Abstract [en]

    This study aims to investigate the ability of different least squares adjustment techniques for detecting deformation. A simulated geodetic netwo rk is used for this purpose. The observations are collected using the Total Station instrument in three epochs and different least squares adjustment methods are used to analyze the simulated network. The applied methods are adjustment-byelement, using variance-covariance components and Tikhonov regularization. For numerical computation, we utilized exist geodetic network around the simulated network and the deformation (changes in the simulated network) imposes to the object using a simulator in each epoch. The obtained results demonstrate that more accurate outcome for detection of small deformation is possible by estimating variance-covariance components. The difference of the estimated and the simulated deformations in the best scenario, i.e., applying variance-covariance components, is 0.2 and 0.1 mm in x and y directions. In comparison with adjustment by element and Tikhonov regularization methods the differences are 1.1 and 0.1 in x direction and 1.4 and 1.1 mm in y direction, respectively. In addition, it is also possible to model the deformation and therefore it can be seen that how the calculated displacement will affect the result of deformation modelling. It has been demonstrated that determining reasonable variance-covariance components is very important to estimate realistic deformation model and monitoring the geodetic networks. 

  • 36.
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute.
    Global earth isostatic model using smoothed Airy-Heiskanen and Vening Meinesz hypotheses2012In: Earth Science Informatics, ISSN 1865-0473, Vol. 5, no 2, p. 93-104Article in journal (Refereed)
  • 37.
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute.
    Impact of compensating mass on the topographic mass: A study using isostatic and non-isostatic Earth crustal models2012In: Acta Geodaetica et Geophysica Hungarica, ISSN 1217-8977, E-ISSN 1587-1037, Vol. 47, no 1, p. 29-51Article in journal (Refereed)
  • 38.
    Bagherbandi, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences. KTH.
    Amin, Hadi
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences. Department of Computer and Spatial Sciences University of Gävle Gävle Sweden.
    Wang, Linsong
    China University of Geosciences; GFZ German Research Centre for Geosciences, Telegrafenberg, Germany.
    Shirazian, Masoud
    Shahid Rajaee Teacher Training University, Tehran, Iran.
    Mantle Viscosity Derived From Geoid and Different Land Uplift Data in Greenland2022In: Journal of Geophysical Research - Solid Earth, ISSN 2169-9313, E-ISSN 2169-9356, Vol. 127, no 8, article id e2021JB023351Article in journal (Refereed)
    Abstract [en]

    The Earth's mass redistribution due to deglaciation and recent ice sheet melting causes changes in the Earth's gravity field and vertical land motion in Greenland. The changes are because of ongoing mass redistribution and related elastic (on a short time scale) and viscoelastic (on time scales of a few thousands of years) responses. These signatures can be used to determine the mantle viscosity. In this study, we infer the mantle viscosity associated with the glacial isostatic adjustment (GIA) and long-wavelength geoid beneath the Greenland lithosphere. The viscosity is determined based on a spatio-spectral analysis of the Earth's gravity field and the land uplift rate in order to find the GIA-related gravity field. We used different land uplift data, that is, the vertical land motions obtained by the Greenland Global Positioning System (GPS) Network (GNET), gravity recovery and climate experiment (GRACE) and glacial isostatic adjustment (GIA) data, and also combined them using the Kalman filtering technique. Using different land uplift rates, one can obtain different GIA-related gravity fields. As shown in this study, the mantle viscosities of 1.9 × 1022 Pa s and 7.8 × 1021 Pa s for a depth of 200–700 km are obtained using ICE-6G (VM5a) model and the combined land uplift model, respectively, and the GIA-related gravity potential signal

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  • 39.
    Bagherbandi, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Amin, Hadi
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Wang, Linsong
    Hubei Subsurface Multi-scale Imaging Key Laboratory, Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan, China.
    Shirazian, Masoud
    Department of geomatics engineering, Civil Engineering Faculty, Shahid Rajaee Teacher Training University, Tehran, Iran..
    Mantle viscosity derived from geoid and different land uplift data in Greenland2022Conference paper (Other academic)
    Abstract [en]

    The Earth’s mass redistribution due to deglaciation and recent ice sheet melting causes changes in the Earth’s gravity field and vertical land motion in Greenland. The changes are because of ongoing mass redistribution and related elastic (on a short time scale) and viscoelastic (on time scales of a few thousands of years) responses. These signatures can be used to determine the mantle viscosity. In this study, we infer the mantle viscosity associated with the glacial isostatic adjustment (GIA) and long-wavelength geoid beneath the Greenland lithosphere. The viscosity is determined based on a spatio-spectral analysis of the Earth’s gravity field and the land uplift rate in order to find the GIA-related gravity field. We used and evaluated different land uplift data, i.e. the vertical land motions obtained by the Greenland Global Positioning System (GPS) Network (GNET), GRACE and Glacial Isostatic Adjustment (GIA) data. In addition, a  combined land uplift rate using the Kalman filtering technique is presented in this study. We extract the GIA-related gravity signals by filtering the other effects due to the deeper masses i.e. core-mantle (related to long-wavelengths) and topography (related to short-wavelengths). To do this, we applied correlation analysis to detect the best harmonic window. Finally, the mantle viscosity using the obtained GIA-related gravity field is estimated. Using different land uplift rates, one can obtain different GIA-related gravity fields. For example, different harmonic windows were obtained by employing different land uplift datasets, e.g. the truncated geoid model with a harmonic window between degrees 10 to 39 and 10 to 25 showed a maximum correlation with the GIA model ICE-6G (VM5a) and the combined land uplift rates, respectively. As shown in this study, the mantle viscosities of 1.6×1022 Pa s and 0.9×1022 Pa s for a depth of 200  to 650  km are obtained using ICE-6G (VM5a) model and the combined land uplift model, respectively, and the GIA-related gravity potential signal.

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  • 40.
    Bagherbandi, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS. KTH Royal Institute of Technology, Stockholm, Sweden.
    Bai, Yongliang
    School of Geosciences, China University of Petroleum (East China), Qingdao, China.
    Sjöberg, Lars
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Tenzer, Robert
    NTIS - New Technologies for the Information Society, Faculty of Applied Sciences, University of West Bohemia, Plzeň, Czechia.
    Abrehdary, Majid
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Miranda, Silvia
    Departamento de Geofísica y Astronomía, FCEFN Universidad Nacional de San Juan, San Juan, Argentina.
    Sanchez, Juan M. Alcacer
    Departamento de Geofísica y Astronomía, FCEFN Universidad Nacional de San Juan, San Juan, Argentina.
    Effect of the lithospheric thermal state on the Moho interface: a case study in South America2017In: Journal of South American Earth Sciences, ISSN 0895-9811, E-ISSN 1873-0647, Vol. 76, p. 198-207Article in journal (Refereed)
    Abstract [en]

    Gravimetric methods applied for Moho recovery in areas with sparse and irregular distribution of seismic data often assume only a constant crustal density. Results of latest studies, however, indicate that corrections for crustal density heterogeneities could improve the gravimetric result, especially in regions with a complex geologic/tectonic structure. Moreover, the isostatic mass balance reflects also the density structure within the lithosphere. The gravimetric methods should therefore incorporate an additional correction for the lithospheric mantle as well as deeper mantle density heterogeneities. Following this principle, we solve the Vening Meinesz-Moritz (VMM) inverse problem of isostasy constrained by seismic data to determine the Moho depth of the South American tectonic plate including surrounding oceans, while taking into consideration the crustal and mantle density heterogeneities. Our numerical result confirms that contribution of sediments significantly modifies the estimation of the Moho geometry especially along the continental margins with large sediment deposits. To account for the mantle density heterogeneities we develop and apply a method in order to correct the Moho geometry for the contribution of the lithospheric thermal state (i.e., the lithospheric thermal-pressure correction). In addition, the misfit between the isostatic and seismic Moho models, attributed mainly to deep mantle density heterogeneities and other geophysical phenomena, is corrected for by applying the non-isostatic correction. The results reveal that the application of the lithospheric thermal-pressure correction improves the RMS fit of the VMM gravimetric Moho solution to the CRUST1.0 (improves ∼ 1.9 km) and GEMMA (∼1.1 km) models and the point-wise seismic data (∼0.7 km) in South America.

  • 41.
    Bagherbandi, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Eshagh, Mehdi
    Avd för naturvetenskap, lantmäteri- och maskinteknik, Institutionen för ingenjörsvetenskap, Högskolan i Väst.
    Combined Moho Estimators2014In: Geodynamics : Research International Bulletin, ISSN 2345-4997, Vol. 1, no 3, p. 1-11Article in journal (Other (popular science, discussion, etc.))
    Abstract [en]

    In this study, we develop three estimators to optimally combine seismic and gravimetric models of Moho surface. The first estimator combines them by their special harmonic coefficients; the second one uses the spherical harmonic coefficients of the seismic model and use integral formula for the gravimetric one. The kernel of the integral terms of this estimator shows that a cap size of 20◦ is required for the integration, but since this integral is presented to combine the low frequencies of the gravimetric model, a low resolution model is enough for the integration. The third estimator uses the gravity anomaly and converts its low frequencies to those of the gravimetric Moho model, meanwhile combining them with those of seismic one. This integral requires an integration domain of 30◦ for the gravity anomalies but since the maximum degree of this kernel is limited to a specific degree, the use of its spectral form is recommended. The kernel of the integral involving the gravity anomalies, developed for recovering high frequencies of Moho, is written in a closed-from formula and its singularity is investigated. This kernel is well-behaving and decreases fast, meaning that it is suitable for recovering the high frequencies of Moho surface.

  • 42.
    Bagherbandi, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute.
    Eshagh, Mehdi
    Royal Institute of Technology (KTH), Stockholm, Sweden, and K. N. Toosi University of Technology, Tehran, Iran .
    Crustal thickness recovery using an isostatic model and GOCE data2012In: Earth Planets and Space, ISSN 1343-8832, E-ISSN 1880-5981, Vol. 64, no 11, p. 1053-1057Article in journal (Refereed)
    Abstract [en]

    One of the GOCE satellite mission goals is to study the Earth's interior structure including its crustal thickness. A gravimetric-isostatic Moho model, based on the Vening Meinesz-Moritz (VMM) theory and GOCE gradiometric data, is determined beneath Iran's continental shelf and surrounding seas. The terrestrial gravimetric data of Iran are also used in a nonlinear inversion for a recovering-Moho model applying the VMM model. The newly-computed Moho models are compared with the Moho data taken from CRUST2.0. The root-mean-square (RMS) of differences between the CRUST2.0 Moho model and the recovered model from GOCE and that from the terrestrial gravimetric data are 3.8 km and 4.6 km, respectively.

  • 43.
    Bagherbandi, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute.
    Eshagh, Mehdi
    Islamic Azad Univ, Dept Surveying.
    Recovery of Moho’s undulations based on the Vening Meinesz–Moritz theory from satellite gravity gradiometry data: A simulation study2012In: Advances in Space Research, ISSN 0273-1177, E-ISSN 1879-1948, Vol. 49, no 6, p. 1097-1111Article in journal (Refereed)
  • 44.
    Bagherbandi, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Farzaneh, Saeed
    Gholamrezaee, Sara
    Parvazi, Kamal
    How accurate are GNSS signals for extracting sea level height and tidal frequencies using GNSS-R technique?2023Conference paper (Refereed)
    Abstract [en]

    Remote sensing observations of Essential Climate Variables (ECVs) provide a means of studying their global and regional impacts. Coastal GNSS stations measure water levels using GNSS Reflectometry (GNSS-R) technique by determining the vertical distance between the antenna and the water surface. In this study, GNSS-R data from four stations over three months were used to estimate sea surface heights (SSH) and assess accuracy using nearest tide gauge observations. Results showed that GNSS signals from GPS, GLONASS, Galileo, and BeiDou were accurate for the SSH estimation. In addition, 145 significant tidal frequencies were extracted using the GNSS-R and tide gauge time series by employing the Least Square Harmonic Estimation (LS-HE) approach. The study demonstrates the usefulness of GNSS-R for tide studies and its potential use alongside tide gauge measurements in coastal locations.

  • 45.
    Bagherbandi, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Gido, Nureldin A. A.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    How isostasy explains continental rifting in East Africa?2020Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    The principle of isostasy plays an important role to understand the relation between different geodynamic processes. Although, it is difficult to find an exact method that delivers a complete image of the Earth structure. However, gravimetric methods are alternative to provide images of the interior of the Earth. The Earth’s crust parameters, i.e. crustal depth and crust-mantle density contrast, can reveal adequate information about the solid Earth system such as volcanic activity, earthquake and continental rifting. Hence, in this study, a combine Moho model using seismic and gravity data is determined to investigate the relationship between the isostatic state of the lithosphere and seismic activities in East Africa. Our results show that isostatic equilibrium and compensation states are closely correlated to the seismicity patterns in the study area. For example, several studies suggest that African superplume causes the rift valley, and consequently differences in crustal and mantle densities occur. This paper presents a method to determine the crustal thickness and crust-mantle density contrast and consequently one can observe low-density contrast (about 200 kg/m3 ) and thin crust (about 30 km) near the triple junction plate tectonics in East Africa (Afar Triangle), which confirms the state of overcompensation in the rift valley areas. Furthermore, the density structure of the lithosphere shows a large correlation with the earthquake activity, sub-crustal stress and volcanic distribution across East Africa.

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  • 46.
    Bagherbandi, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Gido, Nureldin A. A.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Sjöberg, Lars E.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Tenzer, Robert
    Hong Kong Polytechnic University.
    Studying permafrost using GRACE and in situ data in the northern high-latitudes regions2019Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    There is an exceptional opportunity of achieving simultaneous and complementary data from a multitude of geoscience and environmental near-earth orbiting artificial satellites to study phenomena related to the climate change e.g. sea level change, ice melting, soil moisture variation, temperature changes, and earth surface deformations. In this study, we focus on permafrost thawing and its associated gravity change, and organic material changes using GRACE data and other satellite- and ground-based observations. The estimation of permafrost changes requires combining information from various sources, particularly using the gravity field change, surface temperature change, and GIA. The most significant factor for careful monitoring of the permafrost thawing is the fact that this process could be responsible for releasing an additional enormous amount of greenhouse gases emitted to the atmosphere, most importantly to mention Carbone dioxide and Methane that are currently stored in the frozen ground. The results of a preliminary numerical analysis reveal a possible existence of a high correlation between the secular trends of greenhouse gases, temperature and equivalent water thickness in the selected regions. Furthermore, according to our estimates based on processing the GRACE data, the groundwater storage attributed to the due to permafrost thawing increased at the annual rates of 3.4, 3.8, 4.4 and 4.0 cm, in Siberia, northern Alaska, and Canada. Despite a rather preliminary character of our results, these findings indicate that the methodology developed and applied in this study should be improved by incorporating the in situ permafrost measurements.

  • 47.
    Bagherbandi, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences. KTH.
    Jouybari, Arash
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Nilfouroushan, Faramarz
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Ågren, Jonas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences. Lantmäteriet.
    Deflection of Vertical Effect on Direct Georeferencing in Aerial Mobile Mapping Systems: A Case Study in Sweden2022In: Photogrammetric Record, ISSN 0031-868X, E-ISSN 1477-9730, Vol. 37, no 179, p. 285-305Article in journal (Refereed)
    Abstract [en]

    GNSS/INS applications are being developed, especially for direct georeferencing in airborne photogrammetry. Achieving accurately georeferenced products from the integration of GNSS and INS requires removing systematic errors in the mobile mapping systems. The INS sensor's uncertainty is decreasing; therefore, the influence of the deflection of verticals (DOV, the angle between the plumb line and normal to the ellipsoid) should be considered in the direct georeferencing. Otherwise, an error is imposed for calculating the exterior orientation parameters of the aerial images and aerial laser scanning. This study determines the DOV using the EGM2008 model and gravity data in Sweden. The impact of the DOVs on horizontal and vertical coordinates, considering different flight altitudes and camera field of view, is assessed. The results confirm that the calculated DOV components using the EGM2008 model are sufficiently accurate for aerial mapping system purposes except for mountainous areas because the topographic signal is not modelled correctly.

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  • 48.
    Bagherbandi, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences. KTH.
    Jouybari, Arash
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Nilfouroushan, Faramarz
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences. Lantmäteriet.
    Ågren, Jonas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences. Lantmäteriet.
    Importance of precise gravity field modeling in direct georeferencing and aerial photogrammetry: a case study for Sweden2022In: The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLIII-B2-2022XXIV ISPRS Congress (2022 edition), ISPRS , 2022Conference paper (Refereed)
    Abstract [en]

    Direct georeferencing of airborne mobile mapping systems is developing with unprecedented speed using GNSS/INSintegration. Removal of systematic errors is required for achieving a high accurate georeferenced product in mobile mappingplatforms with integrated GNSS/INS sensors. It is crucial to consider the deflection of verticals (DOV) in direct georeferencing dueto the recently improved INS sensor accuracy. This study determines the DOV using Sweden’s EGM2008 model and gravity data.The influence of the DOVs on horizontal and vertical coordinates and considering different flight heights is assessed. The resultsconfirm that the calculated DOV components using the EGM2008 model are sufficiently accurate for aerial photogrammetrypurposes except for the mountainous areas because the topographic signal is not modeled correctly.

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    fulltext
  • 49.
    Bagherbandi, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute. Division of Geodesy and Geoinformatics, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Sjöberg, Lars E.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute.
    A synthetic Earth gravity model based on a topographic-isostatic model2012In: Studia Geophysica et Geodaetica, ISSN 0039-3169, E-ISSN 1573-1626, Vol. 56, no 4, p. 935-955Article in journal (Refereed)
    Abstract [en]

    The Earth's gravity field is related to the topographic potential in medium and higher degrees, which is isostatically compensated. Hence, the topographic-isostatic (TI) data are indispensable for extending an available Earth Gravitational Model (EGM) to higher degrees. Here we use TI harmonic coefficients to construct a Synthetic Earth Gravitational Model (SEGM) to extend the EGMs to higher degrees. To achieve a high-quality SEGM, a global geopotential model (EGM96) is used to describe the low degrees, whereas the medium and high degrees are obtained from the TI or topographic potential. This study differes from others in that it uses a new gravimetric-isostatic model for determining the TI potential. We test different alternatives based on TI or only topographic data to determine the SEGM. Although the topography is isostatically compensated only to about degree 40-60, our study shows that using a compensation model improves the SEGM in comparison with using only topographic data for higher degree harmonics. This is because the TI data better adjust the applied Butterworth filter, which bridges the known EGM and the new high-degree potential field than the topographic data alone.

  • 50.
    Bagherbandi, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute.
    Sjöberg, Lars E.
    Royal Institute of Technology (KTH), Stockholm, Sweden.
    Improving gravimetric–isostatic models of crustal depth by correcting for non-isostatic effects and using CRUST2.02013In: Earth-Science Reviews, ISSN 0012-8252, E-ISSN 1872-6828, Vol. 117, p. 29-39Article, review/survey (Refereed)
    Abstract [en]

    The principle of isostasy is important in different fields of geosciences. Using an isostatic hypothesis for estimating the crustal thickness suffers from the more or less incomplete isostatic model and that the observed gravity anomaly is not only generated by the topographic/isostatic signal but also by non-isostatic effects (NIEs). In most applications of isostatic models the NIEs are disregarded. In this paper, we study how some isostatic models related with Vening Meinez's isostatic hypothesis can be improved by considering the NIE. The isostatic gravity anomaly needs a correction for the NIEs, which varies from as much as 494 mGal to − 308 mGal. The result shows that by adding this correction the global crustal thickness estimate improves about 50% with respect to the global model CRUST2.0, i.e. the root mean square differences of the crustal thickness of the best Vening Meinesz type and CRUST2.0 models are 6.9 and 3.2 km before and after improvement, respectively. As a result, a new global model of crustal thickness using Vening Meinesz and CRUST2.0 models is generated. A comparison with an independent African crustal depth model shows an improvement of the new model by 6.8 km vs. CRUST2.0 (i.e. rms differences of 3.0 and 9.8 km, respectively). A comparison between oceanic lithosphere age and the NIEs is discussed in this study, too. One application of this study can be to improve crustal depth in areas where CRUST2.0 data are sparse and bad and to densify the resolution vs. the CRUST2.0 model. Other applications can be used to infer the viscosity of the mantle from the NIEs signal to study various locations around the Earth for understanding complete, over- and under-compensations of the topography.

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