A study of Typhoon rainfalls using TRMM/ PR and ground gauge observations

In this study, TRMM Precipitation Radar (PR) data set 2A25 and ground gauge measurements from the Taiwan Weather Bureau were used to investigate the characteristics of Typhoon rainfalls occurred near Taiwan. Using ground gauge measurements to validate PR rain retrievals, involving the use of simple linear regression, the quantitative relationships between them were obtained. Overall, PR rain retrievals overestimate ground gauge measurements. In a case study of Typhoon Nali, the order was about 1.3 times, and the value of determination coefficient was higher than 0.7. TRMM/ PR 2A25 data were suitable to study the characteristics of typhoon rainfalls, especially for the analyses of bright band and vertical profiles of typhoon rain bands. The study results show the length in height of bright band ranged from four kilometers to over five kilometers. Noticing that rain bands standing over land were wide broader and shorter than those occurred over oceans.