A comprehensive evaluation of GPM-IMERG V06 and MRMS with hourly ground-based precipitation observations across Canada

Abstract

This study investigates the performance of multiple high-resolution remotely sensed precipitation estimates at hourly and daily time scales over Canada for 2014–2018. Four products of the recently released Integrated Multi-satEllite Retrievals for Global precipitation measurement (IMERG-V06) and the Multi-Radar Multi-Sensor (MRMS) Precipitation Rate data are analyzed for different seasons. Evaluations are based on a suite of metrics to assess different characteristics of precipitation estimates using quality-controlled hourly gauge data considered as the truth. The results suggest that Calibrated precipitation (PrecipitationCal) outperforms the other IMERG products particularly over the Prairies and during fall and summer. Over the western and eastern coastal regions, IMERG tends to overestimate precipitation intensities by ~25%. The discrepancy between satellite and ground-based data is higher for more intense precipitation events. Further analyses indicate that while MRMS tends to overestimate the amount of precipitation, it outperforms the IMERG products based on several metrics, especially in detecting the occurrence of precipitation over the eastern coastal regions. Overall, the study of IMERG V06 and MRMS precipitation estimates at a relatively high temporal resolution indicates that both products have the potential to complement ground-based observations over Canada.