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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.
    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.

  • 6.
    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.

  • 7.
    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.

  • 8.
    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.

  • 9.
    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.

  • 10.
    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.

  • 11.
    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)
  • 12.
    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. 

  • 13.
    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-Heiskanenand Vening Meinesz hypotheses2012In: Earth Science Informatics, ISSN 1865-0473, Vol. 5, no 2, p. 93-104Article in journal (Refereed)
  • 14.
    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)
  • 15.
    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.

  • 16.
    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 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.

  • 17.
    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.

  • 18.
    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)
  • 19.
    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.
    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.

  • 20.
    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.

  • 21.
    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.
    Modelling the density contrast and depth of the Moho discontinuity by seismic and gravimetric–isostatic methods with an application to Africa2012In: Journal of African Earth Sciences, ISSN 0899-5362, Vol. 68, p. 111-120Article in journal (Refereed)
    Abstract [en]

    The crustal thickness (Moho depth) is of interest in several geosciences applications, such as geography, geophysics and geodesy. Usually the crustal depth and density variations are estimated by seismic survey data. As such data collection is very time-consuming and expensive an attractive option could be to use a gravimetric/isostatic model. In this case, realistic estimates for the crustal density and Moho density contrast (MDC) are important. In this study, we first use the seismic crustal thickness of CRUST2.0 model as a known parameter in combination with gravimetric data in estimating the crust–mantle density contrast by the isostatic model of Vening Meinesz–Moritz. We present different models to estimate the MDC and its impact on the modelling of the gravimetric–isostatic Moho depth. The theory is applied to estimate the Moho depth of the African continental crust by using different models for the MDC: (a) constant value (0.6 g/cm3), (b) Pratt–Hayford’s model, (c) CRUST2.0 as input to three gravimetric/isostatic models based on Vening Meinesz–Moritz theory. The isostatic models agree by 5.8–7.1 km in the rms with the regional seismic model at a resolution of 2 x2, and the smallest rms difference at a resolution of 1x1is of

    7.2 km. For comparison, the rms differences of CRUST2.0 and the regional seismic model are 8.8 and 9.1 km at the resolutions of 2 deg (interpolated) and 1 deg respectively. The result suggests that the gravimetric/isostatic Moho model can be used in densification of the CRUST2.0 Moho geometry, and to improve it in areas with poor data.

  • 22.
    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.
    KTH Royal Institute of Technology, Division of Geodesy and Geoinformatics.
    Non-isostatic effects on crustal thickness: A study using CRUST2.0 in Fennoscandia2012In: Physics of the Earth and Planetary Interiors, ISSN 0031-9201, E-ISSN 1872-7395, Vol. 200, p. 37-44Article in journal (Refereed)
  • 23.
    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.
    Sjöberg, Lars E.
    KTH.
    Tenzer, Robert
    Wuhan University, China.
    Abrehdary, Majid
    KTH.
    A new Fennoscandian crustal thickness model based on CRUST1.0 and a gravimetric-isostatic approach2015In: Earth-Science Reviews, ISSN 0012-8252, E-ISSN 1872-6828, Vol. 145, p. 132-145Article, review/survey (Refereed)
    Abstract [en]

    In this paper a new gravimetric-isostatic crustal thickness model (VMM14_FEN) is estimated for Fennoscandia. The main motivation is to investigate the relations between geological and geophysical properties, the Moho depth and crust-mantle density contrast at the crust-mantle discontinuity. For this purpose the Bouguer gravity disturbance data is corrected in two main ways namely for the gravitational contributions of mass density variation due to the different layers of the Earth's crust such as ice and sediments, as well as for the gravitational contribution from deeper masses below the crust. This second correction (for non-isostatic effects) is necessary because in general the crust is not in complete isostatic equilibrium and the observed gravity data are not only generated by the topographic/isostatic masses but also from those in the deep Earth interior. The correction for non-isostatic effects is mainly attributed to unmodeled mantle and core boundary density heterogeneities. These corrections are determined using the recent seismic crustal thickness model CRUST1.0. We compare our modeling results with previous studies in the area and test the fitness. The comparison with the external Moho model EuCRUST-07 shows a 3.3. km RMS agreement for the Moho depth in Fennoscandia. We also illustrate how the above corrections improve the Moho depth estimation. Finally, the signatures of geological structures and isostatic equilibrium are studied using VMM14_FEN, showing how main geological unit structures attribute in isostatic balance by affecting the Moho geometry. The main geological features are also discussed in the context of the complete and incomplete isostatic equilibrium. 

  • 24.
    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.
    Tenzer, Robert
    Institute of Geodesy and Geophysics, School of Geodesy and Geomatics, Wuhan University, Wuhan, China .
    Comparative analysis of Vening-Meinesz Moritz isostatic models using the constant and variable crust-mantle density contrast – a case study of Zealandia2013In: Journal of Earth System Science, ISSN 0973-774X, Vol. 122, no 2, p. 339-348Article in journal (Refereed)
    Abstract [en]

    We compare three different numerical schemes of treating the Moho density contrast in gravimetric inverse problems for finding the Moho depths. The results are validated using the global crustal model CRUST2.0, which is determined based purely on seismic data. Firstly, the gravimetric recovery of the Moho depths is realized by solving Moritz’s generalization of the Vening-Meinesz inverse problem of isostasy while the constant Moho density contrast is adopted. The Pratt-Hayford isostatic model is then facilitated to estimate the variable Moho density contrast. This variable Moho density contrast is subsequently used to determine the Moho depths. Finally, the combined least-squares approach is applied to estimate jointly the Moho depths and density contract based on a priori error model. The EGM2008 global gravity model and the DTM2006.0 global topographic/bathymetric model are used to generate the isostatic gravity anomalies. The comparison of numerical results reveals that the optimal isostatic inverse scheme should take into consideration both the variable depth and density of compensation. This is achieved by applying the combined least-squares approach for a simultaneous estimation of both Moho parameters. We demonstrate that the result obtained using this method has the best agreement with the CRUST2.0 Moho depths. The numerical experiments are conducted at the regional study area of New Zealand’s continental shelf.

  • 25.
    Bagherbandi, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Tenzer, Robert
    The Key Laboratory of Geospace Environment and Geodesy, School of Geodesy and Geomatics, Wuhan University, Wuhan, China.
    Comparative study of the uniform and variable Moho density contrast in the Vening Meinesz-Moritz’s isostatic scheme for the gravimetric Moho recovery2016In: International Association of Geodesy Symposia: 3rd International Gravity Field Service, IGFS 2014; Shanghai; China; 30 June 2014 through 6 July 2014 / [ed] Jin, S.G., Springer Berlin/Heidelberg, 2016, Vol. 144, p. 199-207Conference paper (Refereed)
    Abstract [en]

    In gravimetric methods for a determination of the Moho geometry, the constant value of the Moho density contract is often adopted. Results of gravimetric and seismic studies, however, showed that the Moho density contrast varies significantly. The assumption of a uniform density contrast thus might yield large errors in the estimated Moho depths. In this study we investigate these errors by comparing the Moho depths determined globally for the uniform and variable models of the Moho density contrast. These two gravimetric results are obtained based on solving the Vening Meinesz-Moritz’s inverse problem of isostasy. The uniform model of the Moho density contrast is defined individually for the continental and oceanic lithosphere to better reproduce the reality. The global data of the lower crust and upper mantle retrieved from the CRUST1.0 seismic crustal model are used to define the variable Moho density contrast. This seismic model is also used to validate both gravimetric solutions. Results of our numerical experiment reveals that the consideration of the variable Moho density contrast improves the agreement between the gravimetric and seismic Moho models; the RMS of differences is 5.4 km (for the uniform density contrast) and 4.7 km (for the variable density contrast).

  • 26.
    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. KTH, Geodesy & Geoinformatics, Stockholm, Sweden.
    Tenzer, Robert
    School of Geodesy and Geomatics, Wuhan University, Wuhan, China.
    Geoid-to-Quasigeoid Separation Computed Using the GRACE/GOCE Global Geopotential Model GOCO02S: A Case Study of Himalayas and Tibet2013In: Terrestrial, Atmospheric and Oceanic Science, ISSN 1017-0839, E-ISSN 2223-8964, Vol. 24, no 1, p. 59-68Article in journal (Refereed)
    Abstract [en]

    The geoid-to-quasigeoid correction has been traditionally computed approximately as a function of the planar Bouguer gravity anomaly and the topographic height. Recent numerical studies based on newly developed theoretical models, however, indicate that the computation of this correction using the approximate formula yields large errors especially in mountainous regions with computation points at high elevations. In this study we investigate these approximation errors at the study area which comprises Himalayas and Tibet where this correction reaches global maxima. Since the GPS-leveling and terrestrial gravity datasets in this part of the world are not (freely) available, global gravitational models (GGMs) are used to compute this correction utilizing the expressions for a spherical harmonic analysis of the gravity field. The computation of this correction can be done using the GGM coefficients taken from the Earth Gravitational Model 2008 (EGM08) complete to degree 2160 of spherical harmonics. The recent studies based on a regional accuracy assessment of GGMs have shown that the combined GRACE/GOCE solutions provide a substantial improvement of the Earth’s gravity field at medium wavelengths of spherical harmonics compared to EGM08. We address this aspect in numerical analysis by comparing the gravity field quantities computed using the satellite-only combined GRACE/GOCE model GOCO02S against the EGM08 results. The numerical results reveal that errors in the geoid-to-quasigeoid correction computed using the approximate formula can reach as much as ~1.5 m. We also demonstrate that the expected improvement of the GOCO02S gravity field quantities at medium wavelengths (within the frequency band approximately between 100 and 250) compared to EGM08 is as much as ±60 mGal and ±0.2 m in terms of gravity anomalies and geoid/quasigeoid heights respectively.

  • 27.
    Bagherbandi, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS. Division of Geodesy and Geoinformatics, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Tenzer, Robert
    School of Geodesy and Geomatics, Wuhan University, 129 Luoyu Road, Wuhan, China .
    Sjöberg, Lars E.
    Division of Geodesy and Geoinformatics, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Abrehdary, Majid
    Division of Geodesy and Geoinformatics, Royal Institute of Technology (KTH), Stockholm, Sweden.
    On the residual isostatic topography effect in the gravimetric Moho determination2015In: Journal of Geodynamics, ISSN 0264-3707, E-ISSN 1879-1670, Vol. 83, p. 28-36Article in journal (Refereed)
    Abstract [en]

    In classical isostatic models, a uniform crustal density is typically assumed, while disregarding the crustal density heterogeneities. This assumption, however, yields large errors in the Moho geometry determined from gravity data, because the actual topography is not fully isostatically compensated. Moreover, the sub-crustal density structures and additional geodynamic processes contribute to the overall isostatic balance. In this study we investigate the effects of unmodelled density structures and geodynamic processes on the gravity anomaly and the Moho geometry. For this purpose, we define the residual isostatic topography as the difference between actual topography and isostatic topography, which is computed based on utilizing the Vening Meinesz-Moritz isostatic theory. We show that the isostatic gravity bias due to disagreement between the actual and isostatically compensated topography varies between -382 and 596 mGal. This gravity bias corresponds to the Moho correction term of -16 to 25 km. Numerical results reveal that the application of this Moho correction to the gravimetrically determined Moho depths significantly improves the RMS fit of our result with some published global seismic and gravimetric Moho models. We also demonstrate that the isostatic equilibrium at long-to-medium wavelengths (up to degree of about 40) is mainly controlled by a variable Moho depth, while the topographic mass balance at a higher-frequency spectrum is mainly attained by a variable crustal density.

  • 28.
    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.
    Tenzer, Robert
    Wuhan University, China.
    Sjöberg, Lars
    Royal Institute of Technology (KTH), Stockholm, Sweden.
    Novak, Pavel
    University of West Bohemia, Plzen, Czech Republic.
    Improved global crustal thickness modeling based on the VMM isostatic model and non-isostatic gravity correction2013In: Journal of Geodynamics, ISSN 0264-3707, E-ISSN 1879-1670, Vol. 66, p. 25-37Article in journal (Refereed)
    Abstract [en]

    In classical isostatic models for a gravimetric recovery of the Moho parameters (i.e., Moho depths and density contrast) the isostatic gravity anomalies are usually defined based on the assumption that the topographic mass surplus and the ocean mass deficiency are compensated within the Earth’s crust. As acquired in this study, this assumption yields large disagreements between isostatic and seismic Moho models. To assess the effects not accounted for in classical isostatic models, we conduct a number of numerical experiments using available global gravity and crustal structure models. First, we compute the gravitational contributions of mass density contrasts due to ice and sediments, and subsequently evaluate respective changes in the Moho geometry. Residual differences between the gravimetric and seismic Moho models are then used to predict a remaining non-isostatic gravity signal, which is mainly attributed to unmodeled density structures and other geophysical phenomena. We utilize three recently developed computational schemes in our numerical studies. The apparatus of spherical harmonic analysis and synthesis is applied in forward modeling of the isostatic gravity disturbances. The Moho depths are estimated globally on a 1 arc-deg equiangular grid by solving the Vening-Meinesz Moritz inverse problem of isostasy. The same estimation model is applied to evaluate the differences between the isostatic and seismic models. We demonstrate that the application of the ice and sediment density contrasts stripping gravity corrections is essential for a more accurate determination of the Moho geometry. We also show that the application of the additional non-isostatic correction further improves the agreement between the Moho models derived based on gravity and seismic data. Our conclusions are based on comparing the gravimetric results with the CRUST2.0 global crustal model compiled using results of seismic surveys.

  • 29.
    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. KTH.
    Tenzer, Robert
    Royal Institute of Technology (KTH), Stockholm, Sweden .
    Sjöberg, L.E.
    Wuhan University, Wuhan, China .
    Moho depth uncertainties in the Vening-Meinesz Moritz inverse problem of isostasy2014In: Studia Geophysica et Geodaetica, ISSN 0039-3169, E-ISSN 1573-1626, Vol. 58, no 2, p. 227-248Article in journal (Refereed)
    Abstract [en]

    We formulate an error propagation model based on solving the Vening Meinesz-Moritz (VMM) inverse problem of isostasy. The system ofobservation equations in the VMM model defines the relation between theisostatic gravity data and the Moho depth  by means of a second-order Fredholm integralequation of the first kind. The corresponding error model (derived in aspectral domain) functionally relates the Moho depth errors with the commissionerrors of used gravity and topographic/bathymetric models. The error model alsoincorporates the non-isostatic bias which describesthe disagreement, mainly of systematic nature, between the isostatic andseismic models. The error analysis is conducted at the study area of theTibetan Plateau and Himalayas with the world largest crustal thickness. TheMoho depth uncertainties due to errors of the currently available globalgravity and topographic models are estimated to be typically up to 1-2 km,provided that the GOCE gravity gradient observables improved themedium-wavelength gravity spectra. The errors due to disregarding sedimentarybasins can locally exceed ~2 km. The largest errors (which cause a systematic bias betweenisostatic and seismic models) are attributed to unmodeled mantleheterogeneities (including thecore-mantle boundary) and other geophysical processes. These errors aremostly less than 2 km under significant orogens (Himalayas, Ural), but canreach up to ~10 km under the oceanic crust.

  • 30.
    Baranov, Alexey
    et al.
    Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russian Federation; Institute of Earthquake Prediction Theory and Mathematical Geophysics, Russian Academy of Sciences, Moscow, Russian Federation.
    Tenzer, Robert
    Department of Land Surveying and Geo-Informatics, Hong Kong Polytechnic University, Kowloon, Hong Kong.
    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 Geoinformatics, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Combined Gravimetric–Seismic Crustal Model for Antarctica2018In: Surveys in geophysics, ISSN 0169-3298, E-ISSN 1573-0956, Vol. 39, no 1, p. 23-56Article in journal (Refereed)
    Abstract [en]

    The latest seismic data and improved information about the subglacial bedrock relief are used in this study to estimate the sediment and crustal thickness under the Antarctic continent. Since large parts of Antarctica are not yet covered by seismic surveys, the gravity and crustal structure models are used to interpolate the Moho information where seismic data are missing. The gravity information is also extended offshore to detect the Moho under continental margins and neighboring oceanic crust. The processing strategy involves the solution to the Vening Meinesz-Moritz’s inverse problem of isostasy constrained on seismic data. A comparison of our new results with existing studies indicates a substantial improvement in the sediment and crustal models. The seismic data analysis shows significant sediment accumulations in Antarctica, with broad sedimentary basins. According to our result, the maximum sediment thickness in Antarctica is about 15 km under Filchner-Ronne Ice Shelf. The Moho relief closely resembles major geological and tectonic features. A rather thick continental crust of East Antarctic Craton is separated from a complex geological/tectonic structure of West Antarctica by the Transantarctic Mountains. The average Moho depth of 34.1 km under the Antarctic continent slightly differs from previous estimates. A maximum Moho deepening of 58.2 km under the Gamburtsev Subglacial Mountains in East Antarctica confirmed the presence of deep and compact orogenic roots. Another large Moho depth in East Antarctica is detected under Dronning Maud Land with two orogenic roots under Wohlthat Massif (48–50 km) and the Kottas Mountains (48–50 km) that are separated by a relatively thin crust along Jutulstraumen Rift. The Moho depth under central parts of the Transantarctic Mountains reaches 46 km. The maximum Moho deepening (34–38 km) in West Antarctica is under the Antarctic Peninsula. The Moho depth minima in East Antarctica are found under the Lambert Trench (24–28 km), while in West Antarctica the Moho depth minima are along the West Antarctic Rift System under the Bentley depression (20–22 km) and Ross Sea Ice Shelf (16–24 km). The gravimetric result confirmed a maximum extension of the Antarctic continental margins under the Ross Sea Embayment and the Weddell Sea Embayment with an extremely thin continental crust (10–20 km).

  • 31.
    Barreiro-Gen, Maria
    et al.
    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.
    Carpenter, Angela
    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. School of Earth and Environment, University of Leeds, Leeds, UK.
    von Haartman, Robin
    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.
    Lozano, Rodrigo
    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. Organisational Sustainability Ltd., Cardiff, UK.
    Examining Relations Between Public Participationand Public Expenditure: Opinions from English and French Users on Environmental Issues in the English Channel2019In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 11, no 8, article id 2230Article in journal (Refereed)
    Abstract [en]

    Governments need to decide how to allocate their public expenditure, which is commonly misconstrued as simply targeting social issues. Most scientific literature highlights that the role of public spending is to enhance social welfare and fight poverty and inequality. Nonetheless, public expenditure also includes spending on environmental issues. This paper analyses relations between public participation, support for public expenditure, and pro-environmental behaviour (PEB) intentions in the English Channel region. An online public survey was developed to investigate public use of the English and French sides and the public's willingness to change their behaviour to better protect the Channel region. The survey was undertaken in the summer of 2014 and was answered by 2000 respondents. The Channel region public is willing to participate more in behaviour that involves direct changes or switches between buying/purchasing choices. In contrast, there is less willingness to engage in pro-environmental behaviour intentions that involve more active engagement activities. French respondents were slightly less inclined to change their consumer behaviour intentions, while women and older people were slightly more likely to do so. This research shows that pro-environmental behaviour could positively affect support for proposed public expenditure on environmental issues.

  • 32.
    Barthel, Stephan
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering. Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden.
    Belton, Sophie
    Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden.
    Raymond, Christopher
    Department of Landscape Architecture, Planning and Management, Swedish University of Agricultural Sciences, Alnarp, Sweden.
    Giusti, Matteo
    Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden.
    Fostering Children’s Connection to Nature Through Authentic Situations: The Case of Saving Salamanders at School2018In: Frontiers in Psychology, ISSN 1664-1078, E-ISSN 1664-1078, Vol. 9, article id 928Article in journal (Refereed)
    Abstract [en]

     The aim of this paper is to explore how children learn to form new relationships with nature. It draws on a longitudinal case study of children participating in a stewardship project involving the conservation of salamanders during the school day in Stockholm, Sweden. The qualitative method includes two waves of data collection: when a group of 10-year-old children participated in the project (2015) and 2 years after they participated (2017). We conducted 49 interviews with children as well as using participant observations and questionnaires. We found indications that children developed sympathy for salamanders and increased concern and care for nature, and that such relationships persisted 2 years after participation. Our rich qualitative data suggest that whole situations of sufficient unpredictability triggering free exploration of the area, direct sensory contact and significant experiences of interacting with a species were important for children’s development of affective relationships  with the salamander species and with nature in an open-ended sense. Saving the lives of trapped animals enabled direct sensory interaction, feedback, increased understanding, and development of new skills for dynamically exploring further ways of saving species in an interactive process experienced as deeply meaningful, enjoyable and connecting. The behavioral setting instilled a sense of pride and commitment, and the high degree of responsibility given to the children while exploring the habitat during authentic situations enriched children’s enjoyment. The study has implications for the design of education programs that aim to connect children with nature and for a child-sensitive urban policy that supports authentic nature situations in close spatial proximity to preschools and schools.

  • 33.
    Barthel, Stephan
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Colding, Johan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science. Stockholms Universitet.
    A Critical Perspective on the “Smart City” Model2017Other (Other (popular science, discussion, etc.))
    Abstract [en]

    As urban ecologists we support developing smoother traffic systems, providing citizens with more easily accessible information, and of course promoting citizen-participation and local democracy in political decision-making. However, and as is normally the common destiny when new models for sustainable development are appearing, investments in these “smarter” models run the risk of making people blind to problems that need more immediate concern. In short, governance is a matter of prioritizing among different goals. Governance is also about making sure that strong and powerful enterprises and business interests do not hijack the public debate

  • 34.
    Barthel, Stephan
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Colding, Johan
    Stockholms Universitet.
    The Smart (Cyborg) City Needs Smarter Ecological Resilience Thinking2017Other (Other (popular science, discussion, etc.))
    Abstract [en]

    Employing a sort of a cyborg worldview—meaning a living system of intertwined human and machine parts—the Smart City system is seen as contributing to urban sustainability with the basic assumption that ‘the Internet of Things’ serves social and public ends. These ends include economic benefits, improving efficiency and quality of life for people by optimizing control of infrastructures. In this view, urban residents are at the center of a city’s sustainability transformation, while at the same time serving as “data sources”, providing urban planners (central controllers of the cyborg) various sources of information about human behavior that may or may not be exploited. While various efficiency measures often are beneficial for society, at least in the short term, the discussions of resilience of such a cyborg is mostly entirely avoided.

  • 35.
    Barthel, Stephan
    et al.
    Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden; Department of History, Stockholm University, Stockholm, Sweden.
    Parker, John
    National Center for Ecological Analysis and Synthesis, University of Calilfornia, Santa Barbara, USA.
    Ernstson, Henrik
    Stockholm Resilience Center, Stockholm University, Stockholm, Sweden; African Centre for Cities, University of Cape Town, Rondesbosch, Cape Town, South Africa.
    Food and Green Space in Cities: A Resilience Lens on Gardens and Urban Environmental Movements2015In: Urban Studies, ISSN 0042-0980, E-ISSN 1360-063X, Vol. 52, no 7, p. 1321-1338Article in journal (Refereed)
    Abstract [en]

    This article examines the role played by urban gardens during historical collapses in urban food supply lines and identifies the social processes required to protect two crit- ical elements of urban food production during times of crisis - open green spaces and the collective memory of how to grow food. Advanced communication and transport technologies allow food sequestration from the farthest reaches of the planet, but have markedly increasing urban dependence on global food systems over the past 50 years. Simultaneously, such advances have eroded collective memory of food production, while suitable spaces for urban gardening have been lost. These factors combine to heighten the potential for food shortages when - as occurred in the 20th century - major economic, political or environmental crises sever supply lines to urban areas. This paper considers how to govern urban areas sustainably in order to ensure food security in times of crisis by: evincing the effectiveness of urban gardening during crises; showing how allotment gardens serve as conduits for transmitting collective social-ecological memories of food production; and, discussing roles and strategies of urban environmental movements for protecting urban green space. Urban gardening and urban social movements can build local ecological and social response capacity against major collapses in urban food supplies. Hence, they should be incorporated as central elements of sustainable urban development. Urban governance for resilience should be historically informed about major food crises and allow for redundant food production solutions as a response to uncertain futures.

  • 36.
    Barthel, Stephan
    et al.
    Department of History, Stockholm University, Stockholm, Sweden; Stockholm Resilience Center, Stockholm University, Stockholm, Sweden.
    Parker, John
    National Center for Ecological Analysis and Synthesis, University of California, Santa Barbara, USA; Barrett Honors College, Arizona State University, Tempe, USA.
    Folke, Carl
    Stockholm Resilience Center, Stockholm University, Stockholm, Sweden; Beijer Institute of Ecological Economics, Royal Swedish Academy of Sciences, Stockholm, Sweden.
    Colding, Johan
    Stockholm Resilience Center, Stockholm University, Stockholm, Sweden Beijer Institute of Ecological Economics, Royal Swedish Academy of Sciences, Stockholm, Sweden.
    Urban gardens: pockets of social-ecological memory2014In: Greening in the Red Zone: Disaster, Resilience, and Community Greening Part II / [ed] Keith G. Tidball and Marianne E. Krasny, Dordrecht: Springer Netherlands , 2014, p. 145-158Chapter in book (Refereed)
    Abstract [en]

    It is well known that urban allotment gardens provide important ecosystem services. Their potential to act as sources of local resilience during times of crisis is less appreciated, despite the role they have played as areas of food security during times of crisis in history. Their ability to provide such relief, however, requires that the skills and knowledge needed for effective gardening can be transmitted over time and across social groups. In short, some portion of urban society must remember how to grow food. This chapter proposes that collectively managed gardens function as ‘pockets’ of social-ecological memory in urban landscapes by storing the knowledge and experience required to grow food. Allotment gardeners operate as ‘communities of practice’ with ecosystem stewardship reflecting long-term, dynamic interactions between community members and gardening sites. Social-ecological memories about food production and past crises are retained and transmitted through habits, traditions, informal institutions, artifacts and the physical structure of the gardens themselves. Allotment gardens thus serve as incubators of social-ecological knowledge with experiences that can be accessed and transferred to other land uses in times of crisis, contributing to urban resilience. Conversely, failure to protect these pockets of social-ecological memory could result in a collective ‘forgetting’ of important social-ecological knowledge and reduce social-ecological resilience.

  • 37.
    Bekele, Yared
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    GIS Based Factor Identification for the Change in Occurrence of Genista pilosa: a Case Study in Southern Sweden2012Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study has the objective of identifying the possible environmental constraints that has role for the continuous loss of heathland plant Genista pilosa. The study has assessed different environmental settings where the plant occurs by way of overlaying analysis based on multiple spatial data sets. Thereafter empirical change detection analyses on the land use of the study area have been performed on the GIS environment by combining temporal based remotely sensed spatial data. The result was then analyzed using land use dynamicity model and the rates of change on each land use type are identified. Expansion of human activity, especially the spreading of agricultural land and urbanization, is found to be the most determinant factor for the dramatic loss of the plant. Finally serious attention for the protection of the plant is recommended by mentioning the possible problem that would occur due to a loss of biodiversity.

  • 38.
    Bendt, Pim
    et al.
    Beijer Institute of Ecological Economics, Royal Swedish Academy of Sciences, Stockholm, Sweden; .
    Barthel, Stephan
    Stockholm Resilience Center, Stockholm University, Stockholm, Sweden; Department of History, Stockholm University, Stockholm, Sweden.
    Colding, Johan
    Beijer Institute of Ecological Economics, Royal Swedish Academy of Sciences, Stockholm, Sweden; Stockholm Resilience Center, Stockholm University, Stockholm, Sweden .
    Civic greening and environmental learning in public-access community gardens in Berlin2013In: Landscape and Urban Planning, ISSN 0169-2046, E-ISSN 1872-6062, Vol. 109, no 1, p. 18-30Article in journal (Refereed)
    Abstract [en]

    We analyse environmental learning in public-access community gardens (‘PAC-gardens’) in Berlin, representing public green spaces that are collectively managed by civil society groups. Through extensive fieldwork, and drawing upon social theories of learning, we describe learning communities in four PAC-gardens and analyse factors that influence participation and boundary interaction, that is when experiences brought in from the outside encounter socially defined competences. Results show that these PAC-gardens have self-generated social and physical structures, which to different degrees inhibit or facilitate boundary interactions, whereas skills of individuals to put those to work, in combination with the quality of the surrounding neighbourhoods, can be ascribed for creating broader participation and greater diversity in the content of learning about local sustainability. Identified learning streams included learning about gardening and local ecological conditions; about urban politics, and about social entrepreneurship. We discuss results in relation to environmental learning that combats the generational amnesia in cities about our dependence on nature, where PAC-gardens clearly distinguish themselves from more closed forms of urban gardening such as allotment gardens and gated community gardens. We conclude that PAC-gardens that intertwine gardening with social, political and economic practices can create broader and more heterogeneous learning about social–ecological conditions, and help develop sense-of-place in degraded neighbourhoods.

  • 39.
    Benenson, Itzhak
    et al.
    Department of Geography and Human Environment University Tel Aviv.
    Jiang, Bin
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute.
    Editorial : Bridging the Gap between Urban and Regional Modeling, and Planning Practice2012In: Journal of the Urban and Regional Information Systems Association, ISSN 1045-8077, Vol. 24, no 1, p. 5-7Article in journal (Other academic)
  • 40.
    Berg, Björn
    et al.
    Dipartimento biologia strutturale e funzionale, Complesso universitario di Monte S. Angelo, Napoli, Italy; Department of forest ecology, University of Helsinki, Helsinki, Finland.
    Davey, M. P.
    Department of plant sciences, University of Cambridge, Cambridge, United Kingdom.
    De Marco, A.
    Dipartimento biologia strutturale e funzionale, Complesso universitario di Monte S. Angelo, Napoli, Italy.
    Emmett, B
    Centre for ecology and hydrology, Bangor.
    Faituri, M.
    Department of soils and water, Omar AlMukhtar university, Elbeida, Libyan Arab Jamahiriya.
    Hobbie, S. E.
    Department of ecology, evolution and behavior, University of Minnesota, St. Paul, USA.
    Johansson, Maj-Britt
    University of Gävle.
    Liu, C.
    Department of landscape science and engineering, College of agriculture and biology, Shanghai, ChinaShanghai Jiao Tong university,.
    McClaugherty, C.
    Department of biology, Mount Union college, Alliance, USA.
    Norell, L.
    Unit of applied statistics and mathematics, SLU, Uppsala, Sweden.
    Rutigliano, F. A.
    Dipartimento di scienze ambientali, Seconda Università degli studi di Napoli, Caserta, Italy.
    Vesterdal, L.
    Forest & landscape Denmark, University of Copenhagen, Hørsholm, Denmark.
    Virzo De Santo, A.
    Dipartimento biologia strutturale e funzionale, Complesso universitario de Monte S. Angelo, Napoli, Italy.
    Factors influencing limit values for pine needle litter decomposition: A synthesis for boreal and temperate pine forest systems2010In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 100, no 1, p. 57-73Article in journal (Refereed)
    Abstract [en]

    We synthesized available data for decomposition of pine (Pinus) needle litter in pine forests to determine the litter chemical characteristics and climate factors that explained variation in the limit value, i. e. the level of accumulated mass loss at which the decomposition process either continues at a very low rate or possibly stops. Our data base included 56 separate studies on decomposition of pine needle litter, spanning Scots pine, lodgepole pine, Aleppo pine, stone pine and white pine, mainly incubated at the site of collection. Studies had 5 to 19 samplings, on average 10, and the decomposition was followed to a mass loss ranging from 47 to 83%, on average 67%. The periods from 3.0 to 5.4 years, on average 3.9 years, were of sufficient duration to allow estimates of limit values of decomposition. We used a linear mixed model with regression effects to relate limit values to potential explanatory variables, namely the sites' long-term mean annual temperature (MAT) and mean annual precipitation (MAP) and to substrate-chemistry factors. Regarding the latter, we explored two models; one that included initial concentrations of water solubles, lignin, N, P, K, Ca, Mg, and Mn and one that included only lignin, N, Ca, and Mn to focus on those nutrients known to influence lignin degradation. Using backward elimination significant explanatory variables were determined. For litter decomposed in its site of origin we found the limit value to depend mainly on the initial concentration of Mn, with higher Mn concentrations resulting in higher accumulated mass loss. Thus, litter with higher Mn reached a higher limit value and left a smaller stable fraction. This is likely due to the fact that Mn is an essential component of ligninolytic enzymes important for degrading litter in the later stages of decomposition. Manganese has received little attention in decomposition studies to date. Given its significance in this synthesis, the role of Mn in influencing variation in the late stages of decomposition among ecosystems and among litters of other genera besides Pinus deserves further attention.

  • 41.
    Berg, Björn
    et al.
    Department of Forest Sciences, University of Helsinki, Helsinki, Finland .
    Erhagen, Björn
    Department of Ecology and Environmental Sciences, University of Umeå, Umeå, Sweden .
    Johansson, Maj-Britt
    University of Gävle.
    Nilsson, Mats
    Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå.
    Stendahl, Johan
    Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala.
    Trum, Florence
    Earth and Life Institute, Universite' catolique de Louvain, Louvain-la-Neuve, Belgium .
    Vesterdal, Lars
    Department of Geosciences and Natural Resource Management, University of Copenhagen, Fredriksberg C, Denmark .
    Manganese in the litter fall-forest floor continuum of boreal and temperate pine and spruce forest ecosystems: a review2015In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 358, p. 248-260, article id 15021Article, review/survey (Refereed)
    Abstract [en]

    We have reviewed the literature on the role of manganese (Mn) in the litter fall-to-humus subsystem. Available data gives a focus on North European coniferous forests. Manganese concentrations in pine (Pinus spp.) foliar litter are highly variable both spatially and temporally within the same litter species and for the genus Pinus we found a range from 0.03 to 3.7mgg-1. Concentrations were related negatively to site mean annual temperature (MAT) and annual actual evapotranspiration (AET) for pine species litter but not for that of Norway spruce (Picea abies) as a single species. Combined data for several species showed a highly significant relationship to MAT.Manganese peroxidase is an Mn-dependent enzyme, found in white-rot fungi, essential for the degradation of lignin and ligninlike compounds. The decomposition rates of lignified litter tissue (late phase) is positively related to the litter’s Mn concentration. Further, the Mn concentration is positively related to the limit value for decomposition - the higher the Mn concentration the smaller the stable litter fraction. Manganese release from decomposing litter appears at least in part to be species related. Thus was release from pine needle litter significantly faster (p<. 0.001) than that from the Mn-richer litter of Norway spruce. Over Northern Europe concentrations of total Mn in mor humus as well as extractable Mn in the mineral soil increase with decreasing MAT and over a climatic gradient the Mn concentrations in Norway spruce mor increase more with decreasing MAT than in a gradient with Scots pine. Higher Mn concentrations in humus appear to decrease its stability and result in a higher release of carbon dioxide (CO<inf>2</inf>) and dissolved organic carbon (DOC). We conclude that this may explain (i) the lower amount of carbon (C) in mor layers under Norway spruce as compared to Scots pine as well as the higher amount of C in mineral soil under spruce. The increase in nitrogen (N) concentration in humus, following N fertilization resulted in a decrease in that of Mn. We have found four cases - empirical - with negative interaction between Mn and N; (i) in pine foliar litter fall concentrations of Mn decrease with site MAT whereas those of N increase, (ii) in decomposing late-stage litter with N retarding and Mn stimulating decomposition, (iii) for the stable phase, limit values are related negatively to N and positively to Mn, and (iv) Mn concentrations in humus decrease with MAT whereas those of N increase.

  • 42.
    Bergquist, Arne
    et al.
    Lantmäteriet.
    Brandt, S. Anders
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för samhällsbyggnad.
    Klang, Dan
    Vad är optimal kvalitet på geografisk information som underlag för detaljerad översvämningskartering?2008In: Kart & Bildteknik (Mapping and Image Science), ISSN 1651-792X, no 4, p. 18-20Article in journal (Other (popular science, discussion, etc.))
  • 43.
    Bogetti, Sam
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Three dimensional modeling for flood communication: an exploratory case study using flood extent data from the Testebo River in Gävle, Sweden2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Residents of high-risk flood areas are often unaware and unprepared for extreme flood events. In order to raise awareness and improve preventative measures, methods of communicating the potential hazards, vulnerabilities, and risks associated with flood events need to enhanced. Geovisualizations that incorporate three-dimensional (3D) models of urban environments are being applied more frequently to improve communication of potential flood events to members of the lay-public. Recent studies suggest that the interactive and explorable environments provided by 3D geovisualization tools allow users to visualize complex geospatial data in a manner that is more easily understood than traditional 2D maps. The aim of this study was to examine the use of a 3D model for the purpose of communicating predicted flood levels in residential areas. An exploratory case study was conducted to construct and evaluate a 3D model of previously calculated data from the Testebo River in Gävle, Sweden. Methods for creating the model were developed with information obtained from in-depth literature reviews, and consultations with GIS professionals. To evaluate the communicative ability of the model, usability tests were conducted on a small sample size of participants. Through these processes, an explorable 3D model that represented the 100-year and highest probable flood scenarios in the residential areas of Varva, Strömsbro, Forsby and Stigslund was created. The results of the usability tests indicated the model was an effective visualization and provided appropriate tools for exploration. Although the study identified some limitations of the model and 3D models in general that should be considered, it also provides a valuable foundation on which to develop further studies of 3D models for flood communication purposes along the Testebo River and in other flood-prone areas. 

  • 44. Bommarco, Riccardo
    et al.
    Lönn, Mikael
    Södertörns högskola, Miljövetenskap.
    Danzer, Ulrika
    Pålsson, Karl-Johan
    Torstensson, Peter
    Genetic and phenotypic differences between thistle populations in response to habitat and weed management practices2010In: Biological Journal of the Linnean Society, ISSN 0024-4066, E-ISSN 1095-8312, Vol. 99, no 4, p. 797-807Article in journal (Refereed)
    Abstract [en]

    Rapid evolutionary change is increasingly being recognized as commonplace, but the evolutionary consequences for species and ecosystems under human-induced selection regimes have not been explored in detail, although many species occur in such environments. In a common garden experiment and with amplified fragment length polymorphism markers, we examined whether genetic differentiation has taken place between spatially intermixed populations of creeping thistles Cirsium arvense (Asteraceae) collected from a natural habitat (maritime shores), a semi-natural habitat (road verges) and arable fields under two management regimes: conventional and organic farming. Populations of C. arvense have altered genetically and locally adapted their growth patterns with changed land use. Although plants from different habitats showed similar total biomass production, shoot and root production was higher for maritime populations, suggesting selection for increased competitive ability. Competitive ability then declined in the order semi-natural, conventional farms and organic farms. Thistles in arable fields may be more selected for tolerance against disturbances from herbicides and mechanical weed control. In addition, early shoot sprouting and genetic analysis showed differentiation between plants originating from conventional farms and farms that were converted to organic 9–30 years ago, suggesting some adaptation to altered crop cultivation practices

  • 45.
    Borghero, Cecilia
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Feasibility study of dam deformation monitoring in northern Sweden using Sentinel1 SAR interferometry2018Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Dams are man-made structures that in order to keep functioning and to be considered structurally healthy need constant monitoring. Assessing the deformation of dams can be time consuming and economically costly.

    Recently, the technique of Interferometric Synthetic Aperture Radar (InSAR) has proved its potential to measure ground and structural deformation. This geodetic method represents a cost-effective way to monitor millimetre-level displacements and can be used as supplemental analysis to detect movements in the structure and its surroundings.

    The objective of this work is to assess the practicality of the method through the analysis of the surface deformation of the Ajaure dam located in northern Sweden, in the period 2014-2017, using the freely available Sentinel-1A images. The scenes, 51 in ascending and 47 in descending mode, were processed exploiting the Persistent Scatterer (PS) technique and deformation trends, and time series were produced.

    Built in the 60’s, the Ajaure embankment dam is considered as high consequence, meaning that a failure would cause socio-economic damages to the communities involved and, for this reason, the dam needs constant attention. So far, a program of automatic measurements in situ has been collecting data, which have been used partly to compare with InSAR results.

    Results of the multi temporal analysis of the limited PS points on/around the dam show that the dam has been subsiding more intensely toward the centre, where maximum values are of approximately 5 ± 1.25 mm/year (descending) and 2 ± 1.27 mm/year (ascending) at different locations (separated of approximately 70 m). Outermost points instead show values within -0.7 and 0.9 mm/year, describing a stable behaviour. The decomposition of the rate has furthermore revealed that the crest in the observation period has laterally moved toward the reservoir.

    It has been observed that the operation of loading and unloading the reservoir influence the dam behaviour. The movements recorded by the PS points on the dam also correlate with the air temperature (i.e. seasonal cycle).

    The research revealed that the snow cover and the vegetation could have interfered with the signal, that resulted in a relative low correlation. Therefore, the number of PS points on and around the dam is limited, and comparison with the geodetic data is only based on a few points. The comparison shows general agreement, showing the capacities of the InSAR method.

    The study constitutes a starting point for further improvements, for example observation in longer period when more Sentinel1 images of the study area are collected. Installation of corner reflectors at the dam site and/or by use of high resolution SAR data is also suggested.

  • 46.
    Brandt, S. Anders
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för samhällsbyggnad.
    Betydelse av höjdmodellers kvalitet vid endimensionell översvämningsmodellering2009Report (Other academic)
    Abstract [sv]

    Just nu pågår runt om i Sverige och övriga världen omfattande karteringar för översvämningsrisker. Inte minst på grund av EUs översvämningsdirektiv där det har fastslagits att preliminära riskbedömningar ska ha utförts senast 2011, och för konstaterade riskområden ska riskkartor och riskhanteringsplaner ha producerats senast 2013 respektive 2015. I Sverige har nästan samtliga större vattendrag redan karterats översiktligt, men flera studier har visat att de producerade kartorna är alltför osäkra för att kunna fungera som underlag i många planeringssituationer. Därför måste nytt material tas fram samtidigt som det behövs riktvärden, baserade på kvaliteten av underliggande data, på hur osäkra översvämningskarteringarna är. Denna studie utgör andra delen i ett större projekt ”Kvalitetsbeskrivning av geografisk information för översvämningsmodellering” där det övergripande syftet är att bidra till förståelsen för vilka osäkerheter som finns i samband med översvämningsmodellering. Målet med detta delprojekt är att undersöka hur vattennivåer och översvämningsutbredning förändras vid: stegvis degenerering av höjddata, introduktion av systematiska fel i höjdmodellen, samt olika friktionsvärden på vattendragets botten respektive omgivande mark. Som fallstudie har, liksom i ett tidigare Kris-GIS®-projekt, Eskilstunaån använts. Två områden med olika terrängtyper har undersökts, ett relativt flackt område och ett relativt kuperat område med branta sluttningar ned mot vattendraget, med avsikt att därigenom kunna se skillnader i resulterande översvämning med avseende på terrängens karaktär. Terrängen representerades av miljontals från helikopter laserskannade punkter och vattendragets botten representerades av ekolodade punkter. Vattenflödet simulerades som stationär strömning av storleken 198 m3/s, vilket är SMHIs uppskattning av det högsta beräknade flödet. Som modelleringsverktyg har den endimensionella hydrauliska programvaran HEC-RAS använts och för datapreparering och geografiska analyser har ArcView GIS använts. Följande parametrar undersöktes för att få ett mått på osäkerheten vid försämrade höjddata respektive förändrad markfriktion: vattendragets vattenstånd, bredd, tvärsnittsarea samt översvämningsutbredning. För ökad grad av degenerering av höjddata visade resultaten att vattenstånden endast marginellt ändras medan bredder, tvärsnittsareor och utbredning ändras mer markant. Förutom osäkerhet på grund av degenerering av höjddata (till exempel från referensmodellens 0,78 m cellstorlek till 2-3 m cellstorlek) påverkar av samma storleksordning även osäkerhet i friktionsuppskattning (Mannings n ± 0,01) och inkludering av små systematiska fel (upp till ca 0,1 m i höjdled). Dessutom visade resultaten att osäkerheten skiljer sig markant beroende på hur mycket omgivande mark sluttar mot vattendraget. För planeringsändamål med höga krav rekommenderas höjddata med upplösning upp till 1 m cellstorlek, för allmän detaljplanering upp till 4 m cellstorlek och för översiktlig planering upp till 10-25 m cellstorlek. Vid flacka strandsluttningar bör cellstorleken vara ännu mindre.

  • 47.
    Brandt, S. Anders
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för samhällsbyggnad.
    Betydelse av höjdmodellers kvalitet vid översvämningsmodellering2009In: ULI aktuellt, ISSN 1654-6016, no 1, p. 8-9Article in journal (Other (popular science, discussion, etc.))
  • 48.
    Brandt, S. Anders
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för samhällsbyggnad.
    Conceptualization of hydraulic and sedimentary processes in downstream reaches during flushing of reservoirs2005In: Proceedings of the XXXI IAHR Congress [Elektronisk resurs]: Water engineering for the future : choices and challenges : COEX Seoul September 11-16, 2005, Seoul: Korea Water Resources Association , 2005, p. 2577-2588Conference paper (Refereed)
    Abstract [en]

    The main focus of this paper is to describe the active hydraulic and sedimentary processes in downstream river reaches during flushing of sediments from reservoirs. During flushing extreme amounts of sediment may be released. Therefore, these processes are different than those downstream from dams and reservoirs not subjected to flushing. Hence, also the effects differ, which knowledge of may be of value for biologists, etc. During flushing of a reservoir a wave will be released to the downstream reaches. This wave can be divided into one water part and one sediment part. Initially they are in phase with each other, but with increased distance downstream from the dam, the transported sediment lags behind the water due to different traveling velocities. The paper treats when and where sedimentation occurs, and how this is related to the different traveling velocities of water and sediment. Also included are discussions on how the downstream effects during flushing differ from non-flushing effects, how visualization of effects can enhance both the analysis and communication with planners, politicians, etc., as well as discussions on how the studies of these effects can benefit from improved field-work methods.

  • 49.
    Brandt, S. Anders
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för samhällsbyggnad.
    Föreläsningar - övningar - eller?: en jämförande studie av undervisningsmetoder inom gevärsskytte och geografiska informationssystem2004In: Kunskap och lärande i den högre utbildningen: lärarreflektioner från praktiken / [ed] Sara Dahlström och Göran Fransson, Gävle: Pedagogiska rådet, Högskolan i Gävle , 2004, p. 19-38Chapter in book (Other academic)
  • 50.
    Brandt, S. Anders
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för samhällsbyggnad.
    Rapport från Utbildningssektionens årliga utbildningskonferens2009In: Kart- & bildteknik, ISSN 1651-792X, Vol. 2009, no 3, p. 18-19Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Kartografiska sällskapets utbildningssektion genomför varje år de så kallade lärardagarna, en utbildningskonferens som kretsar kring geografisk information. Tilltänkta deltagare är alla, både utbildare och avnämare, som har intresse av utbildningsfrågor från skol- till universitetsnivå. Den 17 till 18 augusti detta år stod KTH som värd, med Hans Hauska hållande taktpinnen, och med 19 deltagare från ett tiotal olika arbetsgivare.

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