资源环境科技发展态势分析平台

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.