Investigating the Potential of Using Satellite‐Based Precipitation Radars as Reference for Evaluating Multisatellite Merged Products.

Abstract: This work investigates the viability of using the Global Precipitation Mission (GPM) Dual‐frequency Precipitation Radar (DPR) as a reference for evaluating multisatellite precipitation products in locations where a ground‐based reference is not available. The Integrated Multi‐Satellite Retrievals for Global Precipitation Measurement (IMERG) version V05 products (early, late, and final) and the microwave‐only (MW) and infrared‐only (IR) components are evaluated against two reference data sets, derived from the Multi‐Radar/Multi‐Sensor System suite of products (MRMS) and the level‐2 DPR (2ADPR). The analysis focuses on a 2‐year period (2014–2015), excluding winters to evaluate liquid‐phase precipitation only. Systematic and random errors are assessed between the satellite‐based products and the MRMS‐based reference. Systematic error for the IMERG early, late, and final products and the MW component are shown to be comparable to those of 2ADPR, while the IR component exhibits a larger bias. Random errors of the IR estimates are found to be 1 order of magnitude larger than the 2ADPR random error. Thus, the hypothesis of using 2ADPR as a benchmark for quantifying uncertainties associated with IMERG holds true for evaluating random errors associated with IR precipitation estimates. Errors in the IR component are then investigated as a function of climatology and seasonality across contiguous United States. The temperate, oceanic, and subtropical climates show the best performance in terms of probability of detection and success ratio, whereas arid‐desert manifests the smallest root‐mean‐square errors. This work suggests that climatic zone‐specific error characterization model is necessary to estimate uncertainties associated with the IMERG products. [ABSTRACT FROM AUTHOR]