Intercomparisons of the Latest Precipitation Estimates from Satellite, Reanalysis and Merged Products over Alaska

Abstract This study uses Stage IV precipitation data over the state of Alaska to assess and cross-compare precipitation estimates from the most recent versions of multiple precipitation products, including satellite-based passive microwave (PMW; SSMIS-F17, MHS-MetOp-B, MHS-NOAA19, AMSR2, ATMS and GMI in V05 and V07), active microwave (AMW or radar; GPM DPR in V06 and V07), combined active and passive microwave (APMW; DPRGMI in V06 and V07), infrared (AIRS), reanalysis (ERA5, MERRA-2), and satellite-gauge (GPCP V1.3 and GPCP V3.2) products. PMW estimates are generally improved in V07 compared to V05 in terms of overall bias, pattern, and capturing precipitation extremes. DPR and DPRGMI show low skill in capturing different precipitation features. ERA5 and MERRA-2 show the highest agreement with Stage IV for all precipitation rate metrics. AIRS and GPCP capture the overall precipitation pattern and magnitude fairly well, performing better than the radar and comparable to the PMW V07 products, although the geographical maps suggest that they provide a relatively smoothed spatial distribution of mean precipitation rates. The outcomes of this study shed light on the performance of various precipitation products over Alaska (partly representing high-latitude regions) and can be useful to guide the development of multi-sensor products.