| dc.description.abstract | Analysis shows that the accuracy of the rainfall potentials from the Improved Tropical Rainfall Potential (I-TRaP) technique are influenced by the changes of typhoon intensity, the accuracy of the predicted typhoon paths, the satellite-retrieved rainfall algorithms, and so on. One of the non-negligible impacts is from the integrity of typhoon rain bands. Whereas many microwave radiometer images from the polar orbiting platforms (such as DMSP satellites) are often lack of data in some areas and periods because of the satellites’ orbits and revisiting rates. That poses a difficulty when using those microwave observation data to estimate a typhoon’s rainfall rate. In the other hand, the analysis result from the hourly GSMaP data shows that the mountainous terrains of Taiwan Island often cause typhoons’ weakening and further rainfall forecasting errors.
In this study, the Global Satellite Mapping of Precipitation (GSMaP) , a temporal-and-spatial-continuous precipitation data set from integrated microwave and infrared images , are used to improve I-TRaP for better typhoon rainfall predications over Taiwan. The results suggest that there is a better agreement to station-measured rainfalls than TRaP and I-TRaP results did. It gives us an opportunity to use the combined microwave and infrared data for getting more accurate typhoon rainfall predications in the future. Moreover, the accuracy of the forecasting rainfall rates can be further handled and improved with considering the change of typhoon intensity. Then, use the long-term trends to correct the I-TRaP-derived rainfall rates. For instance, due to the typhoon circulations for stronger typhoons generally interact with the mountains significantly and trend to bring more topographic rainfall, and then weaken themselves, making I-TRaP under estimate the rainfall by stronger typhoons. With the historical data, such rainfall estimation errors due to the topographic effect can be reduced again. | en_US |