Use of ASTER GDEM for a simulation of surface echo observed by a space borne rain radar

在从太空对降雨进行雷达观测时，雷达不仅接收到降雨回波，而且还接收到强烈的地面回波。在这种情况下，分离的雨回波和地面回波是必不可少的，因为后者可以被看作是一个杂波的雨观测。本研究探讨了使用高分辨率，30米网格，ASTER GDEM分离的雨回波和地面杂波的可行性。利用ASTER GDEM的高程信息进行模拟，结果表明，在雷达观测高山地区时，与TRMM雷达数据吻合较好。结果表明，利用ASTER GDEM对雨回波和地面回波的分离是有效的。然而，有一个警告：ASTER GDEM的精度在某些地区变得非常低，在使用这些地区的数据时应小心。

In radar observations of rain from space, the radar receives not only rain echo but also a strong surface echo. In such a situation, separation between rain echo and surface echo is essential because the latter can be regarded as a clutter in the rain observation. This study examines the feasibility of using a high resolution, 30-m gridded, ASTER GDEM for the separation of rain echo and surface clutter. A simulation using the height information of ASTER GDEM shows a good agreement with the TRMM radar data obtained when the radar observing high mountain areas. It is shown that the use of ASTER GDEM is useful for the separation of rain echo and surface echo. There is a caution, however: the accuracy of ASTER GDEM becomes very low in certain areas and a care should be taken when using the data of these areas.