Precipitation Extremes Monitoring Using the Near-Real-Time GSMaP Product

A need to monitor precipitation extremes from space is widely recognized, especially for regions where ground-based observations are limited or unavailable. This article examines the usefulness of precipitation extremes monitoring using the Global Satellite Mapping of Precipitation (GSMaP) near-real-time product in the East Asia and Western Pacific region-one of the world's most disaster-prone regions. With case studies and statistical analysis, heavy rainfall and drought detected using the GSMaP Near-real-time Gauge-adjusted Rainfall Product (GNRT6) were validated. Heavy rainfall for daily and weekly precipitation and short-term drought from one month up to three months were defined by a 90th percentile threshold or more and the Standardized Precipitation Index over periods from April 2000 to March 2019, respectively. The results of analyses suggested that the detectability varied depending on the region, such as good detection in dry areas and poor detection in rainy island nations. While the accuracy of GNRT6 is confirmed as being generally better than that of the satellite-only uncorrected product, low detectability can be caused by coarse resolutions of parameters used in the gauge-adjustment technique of the GNRT6 and is regarded as a future task.