Publications in Scientific Journals:

R. De Jeu, W. Wagner, T. Holmes, A.J. Dolman, N. Van De Giesen, J. Friesen:
"Global Soil Moisture Patterns Observed by Space Borne Microwave Radiometers and Scatterometers";
Surveys in Geophysics, 29 (2009), 399 - 420.

English abstract:
Within the scope of the upcoming launch of a new water related satellite
mission (SMOS) a global evaluation study was performed on two available global soil
moisture products. ERS scatterometer surface wetness data was compared to AMSR-E soil
moisture data. This study pointed out a strong similarity between both products in sparse to
moderate vegetated regions with an average correlation coefficient of 0.83. Low correlations
were found in densely vegetated areas and deserts. The low values in the vegetated
regions can be explained by the limited soil moisture retrieval capabilities over dense
vegetation covers. Soil emission is attenuated by the canopy and tends to saturate the
microwave signal with increasing vegetation density, resulting in a decreased sensor
sensitivity to soil moisture variations. It is expected that the new low frequency satellite
mission (SMOS) will obtain soil moisture products with a higher quality in these regions.
The low correlations in the desert regions are likely due to volume scattering or to the
dielectric dynamics within the soil. The volume scattering in dry soils causes a higher
backscatter under very dry conditions than under conditions when the sub-surface soil
layers are somewhat wet. In addition, at low moisture levels the dielectric constant has a
reduced sensitivity in response to changes in the soil moisture content. At a global scale the
spatial correspondence of both products is high and both products clearly distinguish
similar regions with high seasonal and inter annual variations. Based on the global analyses
we concluded that the quality of both products was comparable and in the sparse to moderate vegetated regions both products may be beneficial for large scale validation of
SMOS soil moisture. Some limitations of the studied products are different, pointing to
significant potential for combining both products into one superior soil moisture data set.

Hydrology , Global Soil moisture , Remote sensing , Satellites ,SMOS

"Official" electronic version of the publication (accessed through its Digital Object Identifier - DOI)

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