Ground validation of GPM Day-1 IMERG and TMPA Version-7 products over different rainfall regimes in India

Gautam, Amar Kant , Pandey, Ashish

2022-08-01 THEORETICAL AND APPLIED CLIMATOLOGY 2022   149(卷), 46085(期), (931-943页)

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This study presents a comprehensive evaluation of multi-satellite precipitation estimates against ground rain gauge data over three different climatic regions of India. In this study, performance evaluation of Integrated Multi-satellitE Retrievals for GPM (IMERG) a next-generation rainfall mission for observing global precipitation characteristics has been carried out. The IMERG was also inter-compared with the TRMM Multi-satellite Precipitation Analysis (TMPA) product for using contingency table and statistical methods. The dependences of the two satellite rainfall products were examined, with special focus on the reliance of product performance at different rainfall intensities over three different rainfall regime area of India (Upper Mahanadi Basin, districts of Himachal Pradesh (NW Himalaya) and regions of Rajasthan (Thar Desert)). The analysis was carried out on daily and monthly scales. Results indicated that both the satellite precipitation products (SPPs) IMERG and TMPA precipitation products overestimate the daily precipitation. Both the SPPs show good correlation at daily and monthly precipitation estimations, and the performance of SPPs is better in Thar desert area, but poor in the mountainous region. The results also revealed that IMERG precipitation shows better detection capability of daily rainfall compared to TMPA precipitation estimates for most of the rainfall events. In general, IMERG and TMPA overestimated rainfall depths for all rainfall events. This study suggests that there is a need for emendation in precipitation estimation algorithm and validation against rain gauge precipitation to capture the rain events more accurately in the study area.

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