Chapter 14 - Status of High-Resolution Multisatellite Precipitation Products Across India

Abstract

Following the launch of the Tropical Rainfall Measuring Mission (TRMM) satellite, a precursor to the Global Precipitation Measurement (GPM) mission, several high-resolution multisatellite precipitation products were developed to study the characteristics of tropical and subtropical precipitation. However, multisatellite precipitation products are subject to region and season specific biases and inherent errors, which need to be comprehensively characterized before their integration in any specific application. In this chapter, recent evaluations of several popular TRMM-era high-resolution global or quasiglobal multisatellite precipitation products against gauge-based observations over the Indian subcontinent are highlighted, especially for the southwest monsoon season. The unique geography and complex precipitation processes associated with the southwest monsoon makes India a good test-bed to evaluate any satellite-derived precipitation estimates. All the studies showed that although most of the multisatellite precipitation estimates are able to capture large-scale monsoon rainfall patterns, they have biases and errors. The TRMM Multisatellite Precipitation Analysis (TMPA)-3B42 product is proven to be superior to other TRMM-era multisatellite precipitation estimates. With the launch of the GPM Core Observatory in 2014, two finer resolution multisatellite precipitation products—Integrated Multi-satellitE Retrievals for GPM (IMERG) and Global Satellite Mapping of Precipitation (GSMaP) version 6, were released. Both the GPM-based multisatellite precipitation estimates were also compared with the TMPA-3B42 and gauge-based observations. A preliminary analysis showed a noticeable improvement by GPM-based estimates over TMPA-3B42 in Indian monsoon precipitation estimation. However, a more comprehensive evaluation of GPM-based multisatellite precipitation estimates for longer periods is further required for their widest usage and applications in various sectors. Furthermore, the use of additional local rain gauges with multisatellite precipitation estimates would essentially enhance the quality of precipitation estimates for near real-time applications. There is an operational merged satellite-gauge precipitation estimate that exists specifically for the Indian monsoon region, which was recently upgraded with the IMERG estimate. The procedure of the development of this merged satellite-gauge precipitation estimate and its potential for near real-time applications are also highlighted.