The extreme precipitation and added value of East Asia regional reanalysis system

Abstract

In the study, we evaluate extreme precipitation of the East Asia regional reanalysis system (EARS‐CMA), ERA‐Interim and ERA5 applying Tropical Rainfall Measuring Mission 3B42V7 (TRMM), Climate Prediction Center Morphing Method satellite‐gauge blended product (CMORPH) and CN05.1 over land‐only East Asia in 2008–2017. The added value of EARS‐CMA is also calculated to identify the small‐scale processes at different timescales and spatial resolutions. Compared to TRMM, CMORPH has a better agreement with CN05.1 for the annual, summer and winter spatial pattern and amplitude of most extreme precipitation indices. EARS‐CMA is capable to reproduce amplitude and locations of most extreme precipitation indices for annual and summertime precipitation over China mainland against CN05.1. For land‐only East Asia, ERA5 can reproduce the closest spatial features of various extreme precipitation indices to CMORPH for annual, summer and winter precipitation, followed by EARS‐CMA. All reanalysis datasets show worse skill on the spatial characteristics of duration indicators than on other extreme precipitation indices against CN05.1, but perform better than TRMM and CMORPH. The real added value, potential added value and relative added value of EARS‐CMA show that EARS‐CMA can capture the mesoscale processes over south China, Yangtze River basin, Tibetan Plateau and Indo‐China efficiently, especially the daily and subseasonal timescales over the Tibetan Plateau subregion, which benefits from fine‐scale topographical detail over the complex terrain region in the regional climate model. Also, higher extreme precipitation of aggregating EARS‐CMA than ERA‐Interim can be obtained at the same resolution, which implies that the added value obtained with EARS‐CMA is not merely the contribution of a higher resolution, but also the physical processes resolved by the dynamical downscaling technique.