Evaluation of IMERGV06B over oceans, coastal areas and mountainous regions using Ground Validation-Multi Radar/Multi-Sensor (GV-MRMS)

Quantitative understanding of the water cycle is most important to manage and understand water systems under a changing climate. As one of the fundamental components of the water cycle, precipitation needs to be studied in detail. Satellite-based precipitation products (SPPs) provide the best coverage spatially and temporally at the global scale. Yet, multiple uncertainties are associated with Level-2 PMW and IR precipitation retrievals and Level-3 merged SPPs. There has been an extensive IMERG validation over many areas around the globe which has been highly useful, however there are regions (oceans, coastal areas, and mountain terrains) which suffer from a paucity of validation. Over these regions precipitation estimation remain a challenge and validation are non-common. We need to document the performance and error characteristics of the retrievals to improve them. Main challenge over the coastal areas is strong emissivity gradients, and meanwhile over the mountainous terrain is orographic processes. However limited, some validation results over nontraditional regions can provide valuable indications of the reliability of IMERG where ground observations are limited. This work aims to understand the uncertainty in IMERGV06B over nontraditional regions such as ocean, coasts and mountainous terrains. The analysis of IMERGV06B is studied in detail by considering the Early, Late and Final runs against the high-resolution Ground Validation - Multi Radar/Multi-Sensor (GV-MRMS) at 0.1 and half hourly resolution for the 2015 year. Moreover, PMW and IR only components are analyzed to trace the uncertainty from the Level-2 products. The results of quantification and detection of IMERGV06B over nontraditional regions will be presented.