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Publications in Scientific Journals:

C. Pathe, W. Wagner, D. Sabel, M. Doubkova, J. Basara:
"Using ENVISAT ASAR Global Mode Data for Surface Soil Moisture Retrieval Over Oklahoma, USA";
IEEE Transactions on Geoscience and Remote Sensing, 47 (2009), 2; 468 - 480.



English abstract:
The advanced synthetic aperture radar (ASAR) onboard
of the satellite ENVISAT can be operated in global monitoring
(GM) mode. ASAR GM mode has delivered the first global
multiyear C-band backscatter data set in HH polarization at a
spatial resolution of 1 km. This paper investigates if ASAR GM
can be used for retrieving soil moisture using a change detection
approach over large regions. A method previously developed for
the European Remote Sensing (ERS) scatterometer is adapted
for use with ASAR GM and tested over Oklahoma, USA. The
ASAR-GM-derived relative soil moisture index is compared to
50-km ERS soil moisture data and pointlike in situ measurements
from the Oklahoma MESONET. Even though the scale gap from
ASAR GM to the in situ measurements is less pronounced than
in the case of the ERS scatterometer, the correlation for ASAR
against the in situ measurements is, in general, somewhat weaker
than for the ERS scatterometer. The analysis suggests that this is
mainly due to the much higher noise level of ASAR GMcompared
to the ERS scatterometer. Therefore, some spatial averaging to
3-10 km is recommended to reduce the noise of the ASAR GM soil
moisture images. Nevertheless, the study demonstrates that ASAR
GM allows resolving spatial details in the soil moisture patterns
not observable in the ERS scatterometer measurements while still
retaining the basic capability of the ERS scatterometer to capture
temporal trends over large areas.

Keywords:
Change detection, ScanSAR, scatterometer, soil moisture, synthetic aperture radar (SAR)


"Official" electronic version of the publication (accessed through its Digital Object Identifier - DOI)
http://dx.doi.org/10.1109/TGRS.2008.2004711


Created from the Publication Database of the Vienna University of Technology.