Global Diurnal Cycle of Precipitation from IMERG

This study demonstrates the maturing ability of the Integrated Multi-satellitE Retrievals for GPM (IMERG) for global analyses of the diurnal cycle of precipitation. With a high resolution of 0.1° every half-hour globally over about 20 years, IMERG provides a unique view of global precipitation. The refined intercalibration and interpolation between the sensors in the latest version (V06) leads to greater consistency in the precipitation retrievals over different hours of the day, thus enabling studies of diurnal cycle.

Our evaluation against ground measurements suggests a slight lag in the diurnal phase of only about +0.5 h, an improvement over other satellite-based products. We will demonstrate the global diurnal cycle over different regions around the globe, including the Maritime Continent where accurate representation of precipitation variability in global weather and climate models remains a challenge. Using case studies comparing different regions such as Singapore and Lake Victoria in Africa, we will reveal the intricate interplay between different modes of precipitation variability.

This study demonstrates the unprecedented capability of IMERG in capturing the diurnal cycle of precipitation over different regions around the globe, potentially advancing our understanding in regions of sparse ground measurements and improving its representation in global models.