Seasonal and Diurnal Variations in Rainfall Characteristics over the Tropical Asian Monsoon Region Using TRMM-PR Data

Abstract

Seasonal and diurnal rainfall characteristics, including the rainfall amount (RA), rainfall frequency (RF), and rainfall intensity (RI), were investigated over the tropical Asian monsoon region using Tropical Rainfall Measuring Mission Precipitation Radar (TRMM-PR) data. The results showed that the number of hours of high RF varied seasonally over land, although the diurnal peaks were mostly unchanged. Over Indochina, precipitation ended in the evening in April and May when the RA was low, whereas precipitation lasted until early morning from July to September when the RA was high. The seasonal changes in RF likely contributed to the changes in RA over land. Additionally, RI had two seasonal peaks occurring at the beginning and end of the summer monsoon over land regions; thus, RI was strongest during the two transition seasons. In contrast, both RF and RI had a single seasonal peak over the ocean.