2004 Volume 48 Pages 253-258
This study challenges identification of precipitation over land by microwave radiometer. For that purpose, we prepare database of land surface brightness temperature from 1998 to 2000 using TRMM (Tropical Rainfall Measuring Mission)/TMI (TRMM Microwave Imager) and PR (Precipitation Radar) data. PR data is used for precise identification of non-rainfall condition. These databases can represent inter-annual variation, seasonal variation, diurnal variation, heterogeneity within 1 degree grid, and variation caused by soil moisture.
Rainfall identification is done by comparing the deviation of observed brightness temperature from average and standard deviation of referred database with a negative threshold k0. Only 85GHz observation can give comparable result with existing TMI algorithm (2A12) for all rain rate, but 37GHz observation can give as good performance as 85GHz observation in case of strong rainfall (more than 10mm/hour). When diurnal variation or variation by soil wetness is considered, the performance of lower frequency observation is slightly improved.
