Comparisons of Gauge, TMPA and IMERG Products for Monsoon and Tropical Cyclone Precipitation in Southern China

Abstract

The Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) and Integrated Multi-satellite Retrievals for Global Precipitation Measurement (GPM) Mission (IMERG) products are compared against 447 quality-controlled rain gauges in southern China (SC) during summer (May to August) for the period 2014–2016. The differences of TMPA and IMERG in measuring the monsoon and tropical cyclone (TC) precipitation, considering the mean spatial patterns, and rainfall intensities are evaluated quantitatively. Statistical analysis shows that IMERG has much higher correlations of precipitation frequency (PF) with gauge observations for monsoon and TC precipitation. However, both satellite-based products show much poorer capability in estimating conditional rainfall and PF for TC precipitation, especially for estimating large conditional rainfall in TC systems. The capability of capturing the precipitation events at different rainfall intensities decreases with the increase of rainfall threshold for both monsoon and TC precipitation. Generally, IMERG exhibits a superior ability to detect precipitation at different rainfall intensities than TMPA. In depicting the diurnal cycles, IMERG shows a much better performance in estimating rainfall and PF for monsoon precipitation than TMPA by revealing the comparable diurnal amplitudes to the rain gauges, whereas TMPA fails to accurately estimate the early morning rainfall and PF. As a successor to TMPA, IMERG is a reliable source of precipitation estimates for future studies on precipitation meteorology.