(1) Institute of Industrial Science, University of Tokyo
Soil moisture plays an important role of the memory of water and energy cycle
at land surface.
Microwave sensors have a great potential for soil moisture monitoring.
We analyzed the data of two low resolution active microwave sensors
(TRMM/PR and ERS/Windscatterometer) for continental and/or global
scale.
The longtime average of the backscattering coefficients by these two
sensors are nearly same at similar incident angle, though the
microwave's frequency and polarization are different between these two
sensors.
The temporal change of monthly average backscattering coefficients
correspond with the soil moisture's temporal variation.
Where the incident angle is large, however,
vegetation index are more correlated with the backscattering coefficients.
Even in the region where the surface is moderately covered by the vegetation
(annual average NDVI is about 0.3 to 0.4),
the backscattering coefficients observed by smaller incident angle
can be positively correlated with soil moisture.
However, the sensitivity of the backscattering coefficients to soil moisture
is less by denser vegetation cover and in densely vegetated area (like
tropical forests, annual average NDVI is more than 0.6) the
monitoring of soil moisture may not be expected.
One may think that these results contradict with previous research using
Synthetic Aperture Radars, but the spatial resolution is different.
Two sensors used in this study have low spatial resolutions, so their FOV
may include baresoil, then backscattering coefficients from baresoil
can include the information about soil moisture.
Also, these sattelite remote sensing technique for soil moisture estimation
are compared with off-line simulation of land surface models, and the
advantages of remote sensing technique are discussed.
Submittal Information
Name :
Date :
Shinta SETO
31-May-01-17:18:40
Organization :
Theme :
Institute of Industrial Science, University of Tokyo
Theme 4
Address :
Presentation :
Be607, IIS, University of Tokyo, 4-6-1, Komaba, Meguro-Ku, Tokyo
