Abstract
The latest version of the TRMM (Tropical Rainfall Measuring Mission)/PR (Precipitation Radar) standard product (Version 7; V7) was recently released. This study focuses on heavy rain rate estimated in V7, which are more frequent than in the previous version (Version 6; V6). Surface reference technique is crucial for attenuation correction particularly of heavy rainfall, and becomes more reliable in V7, mainly because of ensemble of multiple SRT methods. Though the accuracy of clutter detection and the validity of Z-R relations are carefully examined, there are still possible rain estimates with extremely heavy rate of more than 300 mm/h. As hourly rain rate, 300 mm/h should be unexceptional, but the time scale of PR measurement may be shorter than 1 hour and these extremely heavy rain rate estimates should be investigated considering the time scale. Relations between heavy rain rates and surface temperature are analyzed with V7 and surface measurements. 99% rain rates in V7 generally increase with the increase of daily surface temperature, though daily rain amount by gauges tends to decrease when daily surface temperature becomes higher than 25 oC, which implies different time scales between PR and gauge measurements.
