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Remote Sens. 2017, 9(4), 359;

A SAR-Based Index for Landscape Changes in African Savannas

Institute for Geography, University of Tübingen, Rümelinstraße 19-23, 72070 Tübingen, Germany
Author to whom correspondence should be addressed.
Academic Editors: Timo Balz, Uwe Soergel, Mattia Crespi, Batuhan Osmanoglu, Nicolas Baghdadi and Prasad S. Thenkabail
Received: 24 March 2017 / Revised: 5 April 2017 / Accepted: 9 April 2017 / Published: 11 April 2017
(This article belongs to the Special Issue Advances in SAR: Sensors, Methodologies, and Applications)
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Change detection is one of the main applications in earth observation but currently there are only a few approaches based on radar imagery. Available techniques strongly focus on optical data. These techniques are often limited to static analyses of image pairs and are frequently lacking results which address the requirements of the user. Some of these shortcomings include integration of user’s expertise, transparency of methods, and communication of results in a comprehensive understandable way. This study introduces an index describing changes in the savanna ecosystem around the refugee camp Djabal, Eastern Chad, based on a time-series of ALOS PALSAR data between 2007 and 2017. Texture based land-use/land cover classifications are transferred to values of natural resources which include comprehensive pertinent expert knowledge about the contributions of the classes to environmental integrity and human security. Changes between the images are analyzed, within grid cells of one kilometer diameter, according to changes of natural resources and the variability of these changes. Our results show the highest resource availability for the year of 2008 but no general decline in natural resources. Largest loss of resources occurred between 2010 and 2011 but regeneration could be observed in the following years. Neither the settlements nor the wadi areas of high ecologic importance underwent significant changes during the last decade. View Full-Text
Keywords: ALOS PALSAR; multi-temporal analysis; resource monitoring; refugee camps; synthetic aperture radar (SAR) ALOS PALSAR; multi-temporal analysis; resource monitoring; refugee camps; synthetic aperture radar (SAR)

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Braun, A.; Hochschild, V. A SAR-Based Index for Landscape Changes in African Savannas. Remote Sens. 2017, 9, 359.

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