TY  - JOUR
A1  - Heine, Iris
A1  - Francke, Till
A1  - Rogass, Christian
A1  - Medeiros, Pedro Henrique Augusto
A1  - Bronstert, Axel
A1  - Förster, Saskia
T1  - Monitoring seasonal changes in the water surface areas of reservoirs using TerraSAR-X time series data in semiarid northeastern Brazil
JF  - IEEE journal of selected topics in applied earth observations and remote sensing
N2  - The 933 km(2) Bengue catchment in northeastern Brazil is characterized by distinct rainy and dry seasons. Precipitation is stored in variously sized reservoirs, which is essential for the local population. In this study, we used TerraSAR-X SM(HH) data for an one-year monitoring of seasonal changes in the reservoir areas from July 2011 to July 2012. The monitoring was based on acquisitions in the ascending pass direction, complemented by occasional descending-pass images. To detect water surface areas, a histogram analysis followed by a global threshold classification was performed, and the results were validated using in situ GPS data. Distinguishing between small reservoirs and similar looking dark areas was difficult. Therefore, we tested several approaches for identifying misclassified areas. An analysis of the surface area dynamics of the reservoirs indicated high spatial and temporal heterogeneities and a large decrease in the total water surface area of the reservoirs in the catchment by approximately 30% within one year.
KW  - Image classification
KW  - monitoring
KW  - radar imaging
KW  - remote sensing
KW  - synthetic aperture radar (SAR)
Y1  - 2014
U6  - https://doi.org/10.1109/JSTARS.2014.2323819
SN  - 1939-1404
SN  - 2151-1535
VL  - 7
IS  - 8
SP  - 3190
EP  - 3199
PB  - Inst. of Electr. and Electronics Engineers
CY  - Piscataway
ER  -