抄録
The backscattering coefficients observed by satellite-based microwave scatterometer are influenced by surface geometric roughness and incident angles. Land surface information can be obtained using these dependences of backscattering coefficients on a different land cover. The Precipitation Rader (PR) on-board the Tropical Rainfall Measuring Misson (TRMM) offers a global and seasonal data set of backscatter coefficients as a by-product. A set of TRMM-PR2A21 data in whole 1998 is utilized in this present paper to investigate land 3urfacc information. The backscattering coefficients at selected regions which belong to different land cover types are analyzed in order to clarify the dependence of backscattering coefficients on incident angle. It is found that the backscattering coefficients significantly depend on land type and incident angle. The seasonal change of backscattering coefficients at each land type is also assessed which should depend on the seasonal change of soil moisture and vegetation. Then, the PR-data are divided into 3 groups based on incident angle, and a global land cover map is produced by classifying land cover into 16 categolies using the 3 groups. The global land cover map is presented and the characteristics of it is described in detail. It is expected that the seasonal change of global land surface information can be obtained utilizing this method in the future.
