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ID: 60195
Title: Spatiotemporal variability of urban growth factors: A global and local perspective on the megacity of Mumbai.
Author: Hossein Shafizadeh-Moghadam, Marco Helbich.
Editor: F.D.van der Meer
Year: 2015
Publisher: Centre for Ecological Sciences
Source: Centre for Ecological Sciences
Reference: Applied Earth Observation and Geoinformation. Vol. 35 Part B. 187-198 (2015).
Subject: APPLIED EARTH OBSERVATION AND GEOINFORMATION.
Keywords: Urban growth, Logistic regression, Autologistic regression, Geographically weighted logistic regression, GIS.
Abstract: The rapid growth of megacities requires special attention among urban planners worldwide, and particularly in Mumbai, India, where growth is very pronounced. To cope with the planning challenges this will bring, developing a retrospective understanding of urban land-use dynamics and the underlying driving -forces behind urban growth is a key prerequisite. This research uses regression-based land-use change models-and in particular non-spatial logistic regression models (LR) and auto-logistic regression models (ALR)-for the Mumbai region over the period 1973-2010, in order to determine the drivers behind spatiotemporal urban expansion. Both global models are complemented by a local, spatial model, the so called geographically weighted logistic regression (GWLR) model, one that explicitly permits variations in driving-forces behind urban growth over time, revealing that LRs and ALRs result in estimated coefficients with comparable magnitudes. Second, all the local coefficients show distinctive temporal and spatial variations. It is therefore concluded that GWLR aids our understanding of urban growth processes, and so can assist context-related planning and policymaking activities when seeking to secure a sustainable urban future.
Location: TE 15 New Biology Building
Literature cited 1: Aljoufie, M., Zuidgeest, M., Brussel, M., van Vliet, J., van Maarseveen, M., 2013. A cellular automata-based land use and transport interaction model applied to Jeddah, Saudi Arabia, Landsc.Urban Plan.112, 89-99. Anselin, L., 2009. Spatial regression. In: Fotheringham, S., Rogerson, P. (Eds), The SAGE Handbook of Spatial Analysis, Los Angeles. Sage Publications Inc, pp. 255-276.
Literature cited 2: Atkinson., P, German, S., Sear, D., Clark, M., 2003. Exploring the relations between riverbank erosion and geomorphological controls using geographically weighted logistic regression. Geogr.Anal.35, 58-82. Augustin, N., Mugglestone, M., Buckland, S., 1996. An autologistic model for the spatial distribution of wildlife.j.Appl.Ecol., 339-347.

ID: 60194
Title: Dynamic simulation of vegetation abundance in a reservoir riparian zone using a sub-pixel Markov model.
Author: Zhaning Gong, Tianxing Cui, Ruiliang Pu, Chuan Lin, Yuzhu Chen.
Editor: F.D.van der Meer
Year: 2015
Publisher: Centre for Ecological Sciences
Source: Centre for Ecological Sciences
Reference: Applied Earth Observation and Geoinformation. Vol. 35 Part B. 175-186 (2015).
Subject: APPLIED EARTH OBSERVATION AND GEOINFORMATION.
Keywords: Vegetation abundance, LSMA, Sub-pixel Markov, Reservoir riparian zone.
Abstract: Vegetation abundance is a significant indicator for measuring the coverage of plant community. It is also a fundamental data for the evaluation of a reservoir riparian zone eco-environment. In this study, a sub-pixel Markov model was introduced and applied to simulate dynamics of vegetation abundance in the Guanting Reservoir Riparian zone based on Landsat Thematic Mapper/Enhanced Thematic Mapper Plus /Operationl Land Imager data acquired between 2001 and 2013. Our study extended Markov model ' s application from a traditional regional scale to a sub-pixel scale. Firstly, Linear Spectral Mixture Analysis (LSMA) was used to obtain fractional images with a five-endmember model consisting of terrestrial plants, aquatic plants, high albedo, low albedo, and bare soil. Then, a sub-pixel transitive probability matrix was calculated. Based on the matrix, we stimulated statuses of vegetation abundance in 2010 and 2013, which were compared with the results created by LSMA. Validations showed that there were only slight differences between the LSMA derived results and the simulated terrestrial plants fractional images for both 2010 and 2013, while obvious differences existed for aquatic plants fractional images, which might be attributed to a dramatically diversity of water level and water discharge between 2001 and 2013. Moreover, the sub-pixel Markov could lead to an RMSE (Root mean square Error) of 0.105 and an R2 of 0.808 for terrestrial plants, and an RMSE of 0.044 and an R2 of 0.784 for aquatic plants in 2010. For the simulated results with the 2013 image, an RMSE of 0.086 and an R2 of 0.779 could be yielded for aquatic plants. These results suggested that the sub-pixel Markov model could yield a reasonable result in a short period. Additionally, an analysis of dynamics of vegetation abundance from 2001 to 2020 indicated that there existed an increasing trend for the average fractional value of terrestrial plants and a decreasing trend for aquatic plants.
Location: TE 15 New Biology Building
Literature cited 1: Aaviskoo, K., 1995.Simulating vegetation dynamics and land use in a mire landscape using a Markov model. Landsc.Urban plan. 31 (1), 129-142, http://dx.doi.org/10.1016/0169-2046 (94) 01045-A. Adams, J.B., Sabol, D.E., Kapos, V., et al., 1995.Classification of multispectral images based on fractions of endmembers: application to land-cover change in the Brazilian Amazon. Remote Sens. Environ. 52 (2), 137 -154, change in the Brazilian Amazon. Remote Sens.Environ.52 (2), 137-154,http://dx.doi.org/10.1016/0034-4257 (94) 00098-8
Literature cited 2: Alex, O.O., Blackburn, G.A., 2011. Forest transition in an ecologically important region: patterns and causes for landscape dynamics in the Niger Delta.Ecol.Indic.11 (5), 1437-1446,http://dx.doi.org/10.1016/j.ecolind.2011.03.017. Asis, A.M.D., Omasa, K., Oki, K., Shinizu, Y., 2008. Accuracy and applicability of linear spectral unmixing in delineating potential erosion areas in tropical watersheds.Int.J.Remote Sens.29 (14), 4151-4171, http://dx.doi.org/10.1080/01431160701874579.

ID: 60193
Title: Drivers of land cover and land use changes in St.Louis metropolitan area over the past 40 years characterized by remote sensing and census population data.
Author: Maitiniyazi Maimaitijiang, Abduwasit Ghulam, J.S. Onesimo Sandoval, Matthew Maimaitiyiming.
Editor: F.D.van der Meer
Year: 2015
Publisher: Centre for Ecological Sciences
Source: Centre for Ecological Sciences
Reference: Applied Earth Observation and Geoinformation. Vol. 35 Part B. 161-174 (2015).
Subject: APPLIED EARTH OBSERVATION AND GEOINFORMATION.
Keywords: Urban growth, Land cover and land use, Geographically weighted regression.
Abstract: In this study, we explored the spatial and temporal patterns of land cover and land use (LCLU) and population change dynamics in the St.Louis Metropolitan Statistical Area. The goal of this paper was to quantify the drivers of LCLU using long-term Landsat data from 1972 to 2010. First, we produced LCLU maps by using Landsat images from 1972, 1982, 1990, 2000, and 2010. Next, tract level population data of 1970, 1980, 1990, 2000, and 2010 were converted to 1-km square grid cells. Then, the LCLU maps were integrated with basic grid cell data to represent the proportion of each land cover category within a grid cell area. Finally, the proportional land cover maps and population census data were combined to investigate the relationship between land cover and population change based on grid cells using Pearson ' s correlation coefficient, ordinary least square (OLS), and local level geographically weighted regression (GWR). Land cover changes in terms of the percentage of area affected and rates of change were compared with population census data with a focus on the analysis of the spatial-temporal dynamics of urban growth patterns. The correlation coefficients of land cover categories and population changes were calculated for two decadal intervals between 1970 and 2010. Our results showed a causal relationship between LCLU changes and population dynamics over the last 40 years. Urban sprawl was positively correlated with population change. However, the relationship was not linear over space and time. Spatial heterogeneity and variations in the relationship demonstrate that urban sprawl was positively correlated with population changes in suburban area and negatively correlated in urban core and inner suburban area of the St. Louis Metropolitan Statistical Area. These results suggest that the imagery reflects processes of urban growth, inner-city decline, population migration, and social spatial inequality. The implications provide guidance for sustainable urban planning and development. We also demonstrate that grid cells allow robust synthesis of remote sensing and socioeconomic data to advance our knowledge of urban growth dynamics from both spatial and temporal scales and its association with population change.
Location: TE 15 New Biology Building
Literature cited 1: Akaike, H., 1974.Anew look at the statistical model identification. IEEE Trans. Autom.Control 19, 716-723. Alperovich, G., Deutsch, J., 1992. Population-density gradients and urbanization measurement. Urban Stud.29, 1323-1328.
Literature cited 2: Anderson, J.R., 1976. Aland use and land cover classification system for use with remote sensor data. US Govrnment Printing Office. Arnfield, A.J., 2003. Two decades of urban climate research: a review of turbulence, exchanges of energy and water, and the urban heat island.Int.J.Climatol.23, 1-26.

ID: 60192
Title: Automated metric characterization of urban structure using building decomposition from very high resolution imagery.
Author: Johannes Heinzel, Thomas Kemper.
Editor: F.D.van der Meer
Year: 2015
Publisher: Centre for Ecological Sciences
Source: Centre for Ecological Sciences
Reference: Applied Earth Observation and Geoinformation. Vol. 35 Part B. 151-160 (2015).
Subject: APPLIED EARTH OBSERVATION AND GEOINFORMATION.
Keywords: Urban characterization, Built-up metrics Mathematical morphology, Very high resolution imagery, South Africa.
Abstract: Classification approaches for urban areas are mostly of qualitative and semantic nature. They produce interpreted classes similar to those from land cover and land use classifications. As a complement to those classes, quantitative measures directly derived from the image could lead to a metric characterization of the urban area. While these metrics lack of qualitative interpretation they are able to provide objective measure of the urban structures. Such quantitative measures are especially important in rapidly growing cities since, beside of the growth in area, they can provide structural information for specific areas and detect changes. Rustenburg, which serves as test area for the present study, is amongst the fastest growing cities in South Africa. It reveals a heterogeneous face of housing and building structures reflecting social and/or economic differences often linked to the spatial distribution of industrial and local mining sites. Up to date coverage with aerial photographs s provided by aerial surveys in regular intervals. Also recent satellite systems provide imagery with suitable resolution. Using such set of very high resolution images a fully automated algorithm has been developed which outputs metric classes by systematically combining important measures of building structure. The measurements are gained by decomposition of buildings directly from the imagery and by using methods from mathematical morphology. The decomposed building objects serve as basis for the computation of grid statistics. Finally a systematic combination of the single features leads to combined metrical classes.
Location: TE 15 New Biology Building
Literature cited 1: Baraldi, A., Parmiggiani, F., 1990. Urban area classification by multispectral SPOT images. IEEE Trans. Geosci. Remote Sens.28, 674-680. Barnsley, M., Barr, S., 1996. Inferring urban land use from satellite sensor images using kernel-based spatial reclassification. Photogra.Eng.Remote Sens.62, 949-958.
Literature cited 2: Baud, I., Kuffer, M., Pfeffer, K., R., Karuppannan, S., 2010. Understanding heterogeneity in metropolitan India: the added value of remote sensing data for analyzing sub-standard residential areas. Int.J.Appl.Earth Observ.Geoinform.12, 359-374. Dell ' Acqua, F., Gamba, P., Lisini, G., 2003. Improvements to urban area characterization using multitemporal and multiangle SAR images.IEEE Trans.Geosci.Remote Sens.41, 1996-2004.

ID: 60191
Title: A comparison of GOCE and drifter-based estimates of the North Atlantic steady-state surface circulation.
Author: Rory J.Bingham, Keith Haines, Daniel Lea.
Editor: F.D.van der Meer
Year: 2015
Publisher: Centre for Ecological Sciences
Source: Centre for Ecological Sciences
Reference: Applied Earth Observation and Geoinformation. Vol. 35 Part A. 140-150 (2015).
Subject: APPLIED EARTH OBSERVATION AND GEOINFORMATION.
Keywords: Mean dynamic topography, ocean currents, North Atlantic.
Abstract: Over the last decade, due to the Gravity Recovery and Climate Experiment (GRACE) mission and, more recently, the Gravity and steady state Ocean Circulation Explorer (GOCE) mission, our ability to measure the ocean ' s mean dynamic topography (MDT) from space has improved dramatically. Here we use GOCE to measure surface current speeds in the North Atlantic and compare our results with a range of independent estimates that use drifter data to improve small scales. We find that, with filtering, GOCE can recover 70 % of the Gulf Steam strength relative to the best drifter-based estimates. In the subpolar gyre the boundary currents obtained from GOCE are close to the drifter-based estimates. Crucial to this result is careful filtering which is required to remove small-scale errors, or noise, in the compound surface. We show that our heuristic noise metric, used to determine the degree of filtering, compares well with the quadratic sum of mean sea surface and formal geoid errors obtained from the error variance-covariance matrix associated with the GOCE gravity model. At a resolution of 100 km the North Atlantic mean GOCE MDT error before filtering is 5 cm with almost all of this coming from the GOCE gravity model.
Location: TE 15 New Biology Building
Literature cited 1: Andersen, O., Knudsen, P., 2009. Te DNSCO8 mean sea surface and mean dynamic topography.J.Geophys.Res.411,http:// dx.doi.org/10.1029/2008jc005179. Balmino, G., 2009. Efficient propagation of error covariance matrices of gravitational models: application to GRACE and GOCE.J.Geod.83, 989-995.
Literature cited 2: Bingham, R., Haines, K., Hughes, C., 2008. Calculating the ocean ' s mean dynamic topography from a mean sea surface and a geoid.J.Atmos.Ocean.Technol.25, 1808-1822,http://dx.doi.org/10.1175/2008JTECH0568.1 Bingham, R.J., 2010. Nonlinear anisotrophic diffusive filtering applied to the ocean ' s mean dynamic topography. Remote Sens.Lett. 1, 205-212, http://dx.doi.org/10.1080/01431161003743165.

ID: 60190
Title: GOCE quasigeoid performance for Norway.
Author: E.Mysen.
Editor: F.D.van der Meer
Year: 2015
Publisher: Centre for Ecological Sciences
Source: Centre for Ecological Sciences
Reference: Applied Earth Observation and Geoinformation. Vol. 35 Part A. 136-139 (2015).
Subject: APPLIED EARTH OBSERVATION AND GEOINFORMATION.
Keywords: EGM2008, GOCE, GPS/leveling, Validation, Height systems.
Abstract: We have compared the EGM08/GOCE quasigeoid with the height anomalies of a precise GPS/leveling network in the south of Norway where the GOCE ground tracks are dense and the gravitational signal has been described as rough. It was found that the inclusion of the GOCE gravity potential can improve the quasigeoid fit with the GPS/leveling network by 1.3 cm, and that this improvement takes place on spatial scales larger than 80 km. We therefore expect that GOCE will improve our knowledge of the marine geoid. It is argued that obtained results cannot be used in a direct way to increase the precision of the Norwegian height system in general due to the short distances between the network points.
Location: TE 15 New Biology Building
Literature cited 1: Bouman, J., Rispens, S., Gruber, T., Koop, R., Schrama, E., Visser, P., Tscherning, C.C., Veicherts, M., 2009. Preprocessing of gravity gradients at the GOCE high-level processing facility, Journal of Geodesy 83, 659-678. Ekman, M., 1989. Impacts of geodynamic phenomena on systems for height and gravity. Bulletin Geodesique 63, 281-296.
Literature cited 2: Ekman, M., 2012, Makinen, J., 1996. Recent postglacial rebound. Gravity change and mantle flow in Fennoscandia. Geophysical Journal International 126, 229-234. Fukushima, T., 2012. Numerical computation of spherical harmonics of arbitrary degree and order by extending exponent of floating point numbers. Journal of Geodesy 86, 271-285.

ID: 60189
Title: Comparison of GGMs based on one year GOCE observations with the EGM08 and terrestrial data over the area of Sudan.
Author: Walyeldeen Godah, Jan Krynski.
Editor: F.D.van der Meer
Year: 2015
Publisher: Centre for Ecological Sciences
Source: Centre for Ecological Sciences
Reference: Applied Earth Observation and Geoinformation. Vol. 35 Part A. 128-135 (2015).
Subject: APPLIED EARTH OBSERVATION AND GEOINFORMATION.
Keywords: Global Geopotential Models, EGM08, GOCE-based GGMs, Free-air gravity anaomalies, Geoid heights, GNSS/leveling.
Abstract: Since 2010, a series of Global Geopotential Models (GGMs) based on Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) satellite gravimetry mission have been released. In this study, the GGMs based on approximately 12 months of GOCE satellite gravity gradiometry (SGG) data have been compared over the area of Sudan with the EGM08 and terrestrial data. Geoid heights and free-air gravity anomalies from four GOCE/GRACE satellite-only GGMs and one GOCE/GRACE GGM combined with terrestrial/altimetric gravity data were compared with the corresponding ones obtained from the EGM08, terrestrial free-air gravity anomalies and GNSS/leveling data. The results reveal that geoid heights and free-air gravity anomalies obtained from the GOCE-based GGMs agree with the corresponding ones from the EGM08 truncated to d/0 200 with standard deviation of 18-20 cm, and 3.4-4.2 mGal, respectively. Their agreement with the terrestrial free-air gravity anomalies and GNSS/leveling geoid heights, in terms of standard deviation is about 5.5 mGal, and about 50cm, respectively.
Location: TE 15 New Biology Building
Literature cited 1: Abdalla, A., 2009. Determination of a Gravimetric Geoid Model of Sudan Using the KTH Method, Master ' s of Science Thesis in Geodesy No.3109, TRITA-GIT EX09-001, Royal Institute of Technology (KTH), Stockholm, Sweden, ISSN 1653-5227; ISRN KTH/GIT/EX-09/001-SE. Abdalla, A., Fashir, H.H., Ali, A., Fairhead, D., 2012. Validation of recent GOCE/GRACE geopotential models over Khartoum State-Sudan. Journal of Geodetic Sciences, http://dx.doi.org/10.2478/v10156-011-035-6
Literature cited 2: Andersen, B., 2010. The DTU10 Gravity field and mean sea surface-improvements in the Arctic. In: 2nd Internal Symposium of the Gravity field recovery by means of the direct numerical method. In: Proceedings of the ESA Living Planet Symposium, 28 June-2July 2010, Bergen, Norway. Bruinsma, S.L., Marty, J.C., Balmino, G., Biancale, R., Foerste, C., Abrikosov,O., Neumayer, H., 2010.GOCE gravity field recovery by means of the direct numerical method. In: Proceedings of the ESA Living Planet Symposium, 28 June-2 July 2010, Bergen, Norway.

ID: 60188
Title: Global gravity field modeling based on GOCE and complementary gravity data.
Author: Thomas Fecher, Ronald Pail, Thomas Gruber
Editor: F.D.van der Meer
Year: 2015
Publisher: Centre for Ecological Sciences
Source: Centre for Ecological Sciences
Reference: Applied Earth Observation and Geoinformation. Vol. 35 Part A. 120-127 (2015).
Subject: APPLIED EARTH OBSERVATION AND GEOINFORMATION.
Keywords: GOCE, Combination, Gravity field model, High performance computing.
Abstract: A combined high-resolution global gravity field model up to degree/order (d/o) 720, including error estimates in terms of a full variance-covariance matrix, is determined from GOCE (Gravity field and steady-state Ocean Circulation Explorer) and complementary gravity field data. GOCE observations, highly accurate in the low to medium wavelength part (~d/ 040-220), are supplemented by GRACE (Gravity Recovery and Climate Experiment) with high accuracy in the low wavelength part (~d/02-150), and altimetric and terrestrial gravity field observations to enhance the spectral resolution of the combined gravity field model. The theory of combining different data sets by least-squares techniques, applying optimum weighting strategies, is illustrated. Full normal equation systems are used to enable stochastic modeling of all individual observations. High performance computing techniques are applied in order to handle normal equations of enormous size (about 2 TB). The quality of the resulting gravity field solution is analyzed by comparisons with independent gravity field models and GPS/leveling observations, and also in the frame of the computation of a mean dynamic topography. The validation shows that the new combined model TUM2013C achieves the quality level of established high-resolution models. Compared to EGM2008, the improvements due to the inclusion of GOCE are clearly visible.
Location: TE 15 New Biology Building
Literature cited 1: Bingham, R.J., Knudsen, P., Andersen, O., Pail, R., 2011. An initial estimate of the North Atlantic steady-state geostrophic circulation from GOCE. Geophysical Research Letters 38 (1), L0 1606. Bingham, R., 2015. A comparison of GOCE and drifter-based estimates of the North Atlantic steady-state surface circulation.Int.J.Appl.Earth Obs.Geoinform.35, 140-150.
Literature cited 2: Bouman, J., Fuchs, M., 2012. GOCE gravity gradients versus global gravity fields models. Geophysical Journal International 189 (2), 846-850, http://dx.doi.org/10.1111/j.1365-246X.2012.05428.x. Bouman, J., Ebbing, J., Meekes, S., Fattah, R., Fuchs, M., Gradmann, S., Haagmans, R., Lieb, V., Schmidt, M., Dettmering, D., Bosch, W., 2015. Goce gravity gradient data for lithospheric modeling.Int.J.Appl.Earth Obs.Geoinform.35, 16-30.

ID: 60187
Title: Geological appraisal over the Singhum-Orissa Craton, India using GOCE, EIGEN6-C2 and in situ gravity data.
Author: S.K.Pal, T.J.Majumdar.
Editor: F.D.van der Meer
Year: 2015
Publisher: Centre for Ecological Sciences
Source: Centre for Ecological Sciences
Reference: Applied Earth Observation and Geoinformation. Vol. 35 Part A. 96-119 (2015).
Subject: APPLIED EARTH OBSERVATION AND GEOINFORMATION.
Keywords: GOCE, EIGEN-6C2, Profile analysis, Geological mapping, Singhbhum-Orissa Craton.
Abstract: The gravity field and derivatives generated with the high resolution EIGEN-6C2 gravity model which includes satellite gravity data of GOCE (Gravity field and steady state Ocean Circulation Explorer) has been utilized for geological appraisal of the Singbhum -Orissa Craton, India. The GOCE only field gravity data and in situ gravity data of the same area have been utilized for comparative assessment to validate the results derived by EIGEN -6C2 gravity data. The GOCE and EIGEN-6C2 Free- air gravity data, respectively, after removing topography effect. The result shows that correlation coefficient and covariance between the Bouguer gravity data have been generated from GOCE and EIGEN-6C2 gravity data, respectively, after removing topography effect. The result shows that correlation coefficient and covariance between the Bouguer gravity anomaly distribution of in situ and EIGEN-6C2 data of the entire study area are 0.68 and 93.9 mgal2, respectively. The GOCE field compares well to the terrestrial derivative fields in the long-wavelength part of the signal. Further, EIGEN-6C2 and in situ Bouguer gravity data have been analyzed using the 1st and 2nd Vertical Derivatives, Analytical Signal and Tilt Derivative mapping techniques. Published geological and structural maps of the area have been overlapped over different derivative maps and the analytical signal map to analyze the correlation with the subsurface geology and geological structures of the area. Major distinct geological signatures, on different derivative maps and analytical signal map, are correlated well with the existing geological map. The TDR derived from the EIGEN-6C2 Bouguer anomaly has been used to map geologic contacts .The source boundaries and depths are determined from the zero contours, and the half distance between ? ?/4 contours or the distance between zero and +?/4 or -?/4 contour of TDR, respectively. The gravity datafenerated from EIGEN-6C2 model provides sufficient resolution for understanding of the geological setting of the Singhbhum-Orissa Craton.
Location: TE 15 New Biology Building
Literature cited 1: Abdul Fattah, R., Meekes, J.A.C., Colella, S., J., Schmidt, M., Ebbing, J., 2013. The application of GOCE satellite gravity data for basin and petroleum system modeling: a case study from the Arabian Penissula. In: Search and Discovery Article # 120130.Posted March 13, 2013. Acharya, A., 1984. Stratigraphic and structural evolution of the rocks of the iron ore basins in Singhbhum-Orissa Iron ore Province, India. CEISM Seminar.Ind.J.Earth Sci.1, 19-28.
Literature cited 2: Acharya, A., 1984.Stratigraphic and structural evolution of the rocks of the iron ore basins in Singhbhum-Orissa Iron Ore Province, India, CEISM Seminar.Ind.J.Earth.Sci.1, 19-28. Agarwal, B.N.P., Lal, T., 1969. Calculation of the second vertical derivative of gravity field.J.Pure Appl.Geophys. 76 (1), 5-16.

ID: 60186
Title: Exploration of tectonic structures with GOCE in Africa and across-continents.
Author: Carla Braitenberg.
Editor: F.D.van der Meer
Year: 2015
Publisher: Centre for Ecological Sciences
Source: Centre for Ecological Sciences
Reference: Applied Earth Observation and Geoinformation. Vol. 35 Part A. 88-95 (2015).
Subject: APPLIED EARTH OBSERVATION AND GEOINFORMATION.
Keywords: Satellite GOCE, Mineral exploration, Macrogeologic lineaments, Suture mapping.
Abstract: The gravity anomaly field over the whole Earth obtained by the GOCE satellite is a revolutionary tool to reveal geologic information on a continental scale for the large areas where conventional gravity measurements have yet to be made. It is, however, necessary to isolate the near-surface geologic signal from the contributions of thickness variations in the crust and lithosphere and the isostatic compensation of surface relief. Here Africa is studied with particular emphasis on selected geological features which are expected to appear as density inhomogeneities. These include cratons and fold belts in the Precambrian basement, the overlying sedimentary basins and magmatism, as well as the continental margins. Regression analysis between gravity and topography shows coefficients that are consistently positive for the free air gravity anomaly and negative for the Bouguer gravity anomaly. The error and scatter on the regression are smallest in oceanic areas, where it is a possible tool for identifying changes in crustal type. The regression analysis allows the large gradient in the Bouguer anomaly signal across continental margins to be removed. After subtracting the predicted effect of known topography from the original Bouguer anomaly field, the residual field shows a continent- wide pattern of anomalies that could be attributed to regional geological structures. A few of these are highlighted, such as those representing Karoo magmatism, the Kibalian foldbelt, the Zimbabwe Craton, the Cameroon and Tibesti volcanic deposits, the Benue Trough and the Luangwa Rift. A reconstruction of the pre-break up position of Africa and South America (the plates forming West Gondwana) is made for the residual GOCE gravity field. The reconstruction allows the positive and negative anomalies to be compared across the continental fragments, and so helps identify common geologic units that extend across both the now-separate continents.
Location: TE 15 New Biology Building
Literature cited 1: Amante, C., Eakins, B.W., 2009. ETOP01 1 Arc-Minut Global Relief Model: Procedures, Data Sources and Analysis.NOAA Technical Memorandum NESDIS NGDC-24. Alvarez, O., Gimenez, M., Braitenberg, C., Folguera, A., 2012. GOCE satellite derived gravity and gravity gradient corrected for topographic effect in the South Central Andes Region.Geophys.J.Int.190, 941-959, http://dx.doi.org/10.1111/j.1365-246X.2012.05556.X.
Literature cited 2: Begg, G.C., Griffin, W.L., Natapov, L.M., O ' Reilly, S.Y., Grand, S.P., O ' Neill,C.J.,Hronsky, J.M.A., Poudjom Djomani, Y., Swain, C.J., Deen, T., Bowden, P., 2009. The lithospheric architecture of Africa: seismic tomography, mantle petrology, and tectonic evolution.Geosphere 5, 23-50, http://dx.doi.org/10.1130/GES00179.1. Bomfim, E., Braitenberg, C., Molina, E., 2013. Mutual evaluation of global gravity models (EGM2008 and GOCE) and terrestrial data in Amazon Basin, Brazil.Geophys.J.Int.,http://dx.doi.org/10.1093/gji/ggt283.

ID: 60185
Title: A refined model of sedimentary rock cover in the southeastern part of the Congo basin from GOCE gravity and vertical gravity gradient observations.
Author: Zdenek Martinec, Javier Fullea.
Editor: F.D.van der Meer
Year: 2015
Publisher: Centre for Ecological Sciences
Source: Centre for Ecological Sciences
Reference: Applied Earth Observation and Geoinformation. Vol. 35 Part A. 70-87 (2015).
Subject: APPLIED EARTH OBSERVATION AND GEOINFORMATION.
Keywords: GOCE gravity gradients, Congo sedimentary basin, Helmert transformation, Inverse gradiometric problem, Sediment density contrast.
Abstract: We aim to interpret the vertical gravity and vertical gravity gradient of the GOCE-GRACE combined gravity model over the southeastern part of Congo basin to refine the published model of sedimentary rock cover. We use the GOCO03S gravity model and valuate its spherical harmonic representation at or near the Earth ' s surface. In this case, the gradiometry signals are enhanced as compared to the original measured GOCE gradients at satellite height and better emphasize the spatial pattern of sedimentary geology. To avoid aliasing, the omission error of the modeled gravity induced by the sedimentary rocks is adjusted to that of the GOCO03s gravity model. The mass-density Green ' s functions derived for the a priori structure of the sediments show a slightly greater sensitivity to the GOCO03S vertical gravity gradient than to the vertical gravity. Hence, the refinement of the sedimentary model is carried out for the vertical gravity gradient over the basin, such that a few anomalous values of the GOCO03S-derived vertical gravity gradient are adjusted by refining the model. We apply the 5-parameter Helmert ' s transformation, defined by 2 translations, 1 rotation and 2 scale parameters that are searched for by the steepest descent method. The refined sedimentary model is only slightly changed with respect to the original map, but it significantly improves the fit of the vertical gravity and vertical gravity gradient over the basin. However, there are still spatial features in the gravity and gradiometric data that remain unfitted by the refined model. These may be due to lateral density variation that is not contained in the model, a density contrast at the Moho discontinuity, lithospheric density stratifications or mantle convection. In a second step, the refined sedimentary model is used to find the vertical density stratification of sedimentary rocks. Although the gravity data can be interpreted by a constant sedimentary density, such a model does not correspond to the gravitational compaction of sedimentary rocks. Therefore, the density model is extended by including a linear increase in density with depth. Subsequent L2 and L? norm minimization procedures are applied to find the density parameters by adjusting both the vertical gravity and the vertical gravity gradient. We found that including the vertical gravity gradient in the interpretation of the GOCO03S-derived data reduces the non-uniqueness of the inverse gradiometric problem for density determination. The density structure of the sedimentary formations that provide the optimum predictions of the GOCO03S-derived gravity and vertical gradient of gravity consists of a surface density contrast with respect to surrounding rocks of 0.24-0.28 g/cm3 and its decrease with depth of 0.05-0.25 g/cm3 per 10 km. Moreover, the case where the sedimentary rocks are gravitationally completely compacted in the deepest parts of the basin is supported by L? norm minization. However, this minimization also allows a remaining density contrast at the deepest parts of the sedimentary basin of about 0.1 g/cm3.
Location: TE 15 New Biology Building
Literature cited 1: Bouman , J., Fuchs, M.J., 2012. GOCE gravity gradients versus global gravity field models. Geophys. J.Int. 189, 846-850,http://dx.doi.org/10.1111/j.1365-246X.2012.05428.x Buiter, S.J.H., Steinberger, B., Medvedev, S., Tetreault, J., 2012. Could the mantle have caused subsidence of the Congo Basin.Tectonophysics 514-517, 62-80.
Literature cited 2: Crosby, A.G., Fishwick, S., White, N., 2010 .Structure and evolution of the intracratonic Congo Basin.Geochem.Geophys.Geosyst.11 (6), QO6010, http: //dx.doi.org/10.1029/2009GC003014. Daly, M.C., Lawrence, S.R., Diemu-Tshiband, K., Matouana, B., 1992. Tectonic evolution of the Cuvette Centrale, Zaire.J.Geol.Soc.Lond.149, 539-546,http://dx.doi.org/10.1029/2009GC003014.

ID: 60184
Title: Perturbing effects of sub-lithospheric mass anomalies in GOCE gravity gradient and other gravity data modeling: Application to the Atlantic -Mediterranean transition zone.
Author: J. Fullea, J. Rodriguez-Gonzalez, M.Charco, Z. Martinec, A. Negredo, A. Villasenor.
Editor: F.D.van der Meer
Year: 2015
Publisher: Centre for Ecological Sciences
Source: Centre for Ecological Sciences
Reference: Applied Earth Observation and Geoinformation. Vol. 35 Part A. 54-69 (2015).
Subject: APPLIED EARTH OBSERVATION AND GEOINFORMATION.
Keywords: Lithosphere-asthenosphere boundary (LAB) GOCE gravity gradients, Geophysical-petrological modeling, Subduction, Alboran Basin, Seismic tomography.
Abstract: The GOCE (Gravity field and steady-state Ocean Circulation Explorer) mission, launched on March 2009, included a new type of satellite instrument, an on-board three-axis gradiometer able to measure the Earth ' s gravity gradients at the satellite height (255km). The potential of this new type of measurement and its derived products (i.e.), global gravity field models), together with other land-based geophysical observables (Bouguer and geoid anomalies), to image sub-lithospheric thermal and compositional anomalies is evaluated in this study. We focus on the Atlantic-Mediterranean Transition Region (AMTR) the diffuse, transpressive contact between the Iberian Peninsula and North Africa. The present-day lithospheric structure in the area is characterized by a wide band of active deformation, large lateral variations in the lithosphere and the presence of a positive seismic-velocity anomaly in the uppermost mantle beneath the Betics and westernmost Alboran Basin-Gibralter Arc. Here, the perturbing effects of deep, sub-lithospheric density anomalies in GOCE gravity gradients and other land-based geophysical data are assessed, and its impact in lithospheric-scale geophysical-petrological modeling within a thermodynamically consistent framework analyzed. Some of the gravity gradients computed at the satellite altitude are rather sensitive to the presence of even a relatively small sub-lithospheric cold slab, like the one observed in the AMTR, showing the potential of the new GOCE data to map upper mantle anomalies. Lithospheric models ignoring the AMTR sub-lithospheric heterogeneities could be significantly biased. In particular, extreme change of 4-6 km and 60-70 km in the crustal and lithospheric thickness, respectively, are required to include sub-lithospheric mantle contributions to land-based and satellite gravity data.
Location: TE 15 New Biology Building
Literature cited 1: Afonso, J.C., Fernandez, M., Ranalli, G., Griffin, W.L., Connolly, J.A.D., 2008. Integrated geophysical-petrological modeling of the lithosphere and sublithospheric upper mantle: methodology and applications.Geochem.Geophys.Geosys.9, Q05008, http://dx.doi.org/10.1029/02007 GC001834. Alvarez, O., Gimenez, M., Braitenberg, C., Folguera, A., 2012. GOCE satellite derived gravity and gravity gradient corrected for topographic effect in the South Central Andes region.Geophys.J.Int.190, 941-959.
Literature cited 2: Bezada, M.J., Humphreys, E.D., Toomey, D.R., Harnafi, M., Davila, J.M., Gallart, J., 2013. Evidence for slab roolback in westernmost Mediterranean from improved upper mantle imaging. Earth Planet.Sci.Lett.368, 51-60. Bijwaard, H., Spakman, W., 2000. Non-linear global p-wave tomography by iterate linearized inversion.Geophys.J.Int.141, 71-82.

ID: 60183
Title: 3D object-oriented image analysis in 3D geophysical modeling: Analysis the central part of the East African Rift System.
Author: I.Fadel, M. van der Meijde, N. Kerle, N.Lauritsen.
Editor: F.D.van der Meer
Year: 2015
Publisher: Centre for Ecological Sciences
Source: Centre for Ecological Sciences
Reference: Applied Earth Observation and Geoinformation. Vol. 35 Part A. 44-53 (2015).
Subject: APPLIED EARTH OBSERVATION AND GEOINFORMATION.
Keywords: Satellite gravity, 3D gravity model, Object-oriented image analysis, Inversion, Tanzania Craton, Seismic tomography.
Abstract: Non-uniqueness of satellite gravity interpretation has traditionally been reduced by using a priori information from seismic tomography models. This reduction in the non-uniqueness has been based on velocity -density conversion formulas or user interpretation of the 3D subsurface structures (objects) based on the seismic tomography models and then forward modeling these objects. However, this form of object-based approach has been done without a standardized methodology on how to extract the sub-surface structures from the 3D models. In this research, a 3D object-oriented image analysis (3D OOA) approach was implemented to extract the 3D subsurface structures from geophysical data. The approach was applied on a 3D shear wave seismic tomography model of the central part of the East African Rift System. Subsequently, the extracted 3D objects from the tomography model were reconstructed in the 3D interactive modeling environment IGMAS+, and their density contrast values were calculated using an object-based inversion technique to calculate the forward signal of the objects and compare it with the measured satellite gravity. Thus, a new object-based approach was implemented to interpret and extract the 3D subsurface objects from 3D geophysical data. We also introduce a new approach to constrain the interpretation of the satellite gravity measurements that can be applied using any 3D geophysical model.
Location: TE 15 New Biology Building
Literature cited 1: Adams, A., Nyblade, A., Weeraratne, D., 2012. Upper mantle shear wave velocity structure beneath the East African plateau: evidence for a deep, plateauwide low velocity anomaly. Geophysical Journal International 189 (1). 123-142. Bassin, C., Laske, G., Masters, G., 2000.The current limits of resolution for surface wave tomography in North America. EOS Transactions AGU 81, F897.
Literature cited 2: Bezada, M.J., Zelt, C.A., 2011. Gravity inversion using seismically derived crustal density models and genetic algorithms: an application to the Caribbean-South American plate boundary. Geophysical Journal International 185 (2), 577-592. Birch, F., 1961. The velocity of compressional waves in rocks to 10 kilobars: 2. Journal of Geophysical Research 66 (7), 2199-2224.

ID: 60182
Title: GEMMA: An Earth crustal model based on GOCE satellite data.
Author: M.Reguzzoni, D. Sampietro
Editor: F.D.van der Meer
Year: 2015
Publisher: Centre for Ecological Sciences
Source: Centre for Ecological Sciences
Reference: Applied Earth Observation and Geoinformation. Vol. 35 Part A. 31-43 (2015).
Subject: APPLIED EARTH OBSERVATION AND GEOINFORMATION.
Keywords: Earth crustal model, Global Moho model, GOCE satellite, Inverse gravimetric problem.
Abstract: The boundary between Earth ' s crust and mantle is commonly modeled as a discontinuity surface, the so-called Moho. Although in some regions of the world this model may be too approximate or even unrealistic, globally speaking it can provide a key to read several long wavelength geophysical signals. Recent research activities have shown the possibility to estimate the Moho discontinuity worldwide from global gravity field model, however usually the solution of this inverse problem requires strong unrealistic hypotheses.
Location: TE 15 New Biology Building
Literature cited 1: Amante, C., Eakins, B.W., 2009. Etopo1 1arc-minute global relief model: procedures, data sources and analysis, NOAA Technical Memorandum NESDIS NGDC-24, March 2009, 19pp. Bassin, C., Laske, G., Masters, G., 2000. The current limits of resolution for surface wave tomography in North America.EOS Trans.AGU 81.
Literature cited 2: Braitenberg, C., Mariani, P., Pivetta, T., 2011. GOCE observations in exploration geophysics. In: Proceedings of the 4th International GOCE User Workshop, Technische Universitat Munchen (TUM), Munich, Germany (ESA SP-696, July 2011). Carlson, R., Raskin, G., 1984. Density of the ocean crust. Nature 311, 555-558.

ID: 60181
Title: GOCE gravity gradient data for lithospheric modeling.
Author: Johannes Bouman, Jorg Ebbing, Sjef Meekes, Rader Abdul Fattah, Martin Fuchs, Sofie Gradman, Roger Haagmans, Verena Lieb, Michael Schmidt, Denise Dettmering, Wolfgang Bosch.
Editor: F.D.van der Meer
Year: 2015
Publisher: Centre for Ecological Sciences
Source: Centre for Ecological Sciences
Reference: Applied Earth Observation and Geoinformation. Vol. 35 Part A. 16-30 (2015).
Subject: APPLIED EARTH OBSERVATION AND GEOINFORMATION.
Keywords: GOCE gravity gradients, Lithosphere, Moho, Heat flow determination.
Abstract: The gravity field and steady-study Ocean Circulation Explorer (GOCE) is the European Space Agency ' s (ESA) satellite gravity mission to determine the Earth ' s mean gravity field. GOCE delivers gravity gradients, a new type of satellite data. We study how these data can improve modeling of the Earth ' s lithosphere. We discuss the use of the original GOCE gravity gradients versus the use of gravity gradients in grids at satellite altitude or close the Earth ' s surface and conclude that grids are easier to handle than the original data because one does not have to deal with very different error characteristics of the different gradients, given in a rotating frame at varying heights. The downward continuation to the surface enhances signal and better reflects the near-surface geology. But this does not outweight the amplification of noise and omission errors, which is why we recommend using the field at mean satellite altitude for lithospheric modeling. The North-East Atlantic region is ideal to analyze the additional value of GOCE gravity gradients because it is well-studied region in terms of regional geophysics. We calculated the gradient sensitivity for crustal depth slices using a 3D lithospheric model. This reveals that especially interfaces with large density contrasts have a distinct signal in the gravity gradients, but that they are quite insensitive to intracrustal density sources, which can have quite a large effect on surface gravity data. We also show that the satellite gradients have a depth sensitivity well suited to study the upper mantle density structure, making them complementary to gravity and seismic tomography. In the underexplored Rub ' al-Khali area the GOCE vertical gradient was used to invert for crustal thickness. The updated Moho model was used to update the heat flow model and source rock maturity maps, which are generally consistent with known source rock maturity trends in the surrounding regions. GOCE gradients are therefore useful to map crustal thickness and deep regional structures for frontier areas. In combination with other data, heat flow can be modeled which is essential for basin maturity evaluation.
Location: TE 15 New Biology Building
Literature cited 1: Abu-Ali, M.A., Rudkiewicz, J.L.L, McGillivray, J.G., Behar, F., 1999. Paleozoic petroleum system of Central Saudi Arabia. GeoArabia. GeoArabia 4, 321-336. Al-Damegh, K., Sandvol, E., Barazangi, M., 2005. Crustal structure of the Arabian Plate: new constraints from the analysis of teleseismic receiver functions. Earth Planet.Sci.Lett.231, 177-196.
Literature cited 2: Al-Jallal, A.I., 1995. The khuff formation-its reservoir potential in Saudi Arabia and other gulf countries. In: Al-Husseini, M.I. (ed). Geo-94, Middle East Petroleum Geosciences Conference.Gulf Petrolink, Manama. Al.Lazki, A.I., Seber, D., Sandvol, E., Barazangi, M., 2002. A crustal transect across the Oman Mountains of the eastern margin of Arabia. GeoArabia 7, 47-78.