Global precipitation system size

Abstract

The size of precipitation systems is an important parameter of precipitation process and dynamics. This study uses the latest Integrated Multi-satellitE Retrievals for Global Precipitation Measurement data during 2015–2019 to investigate the global distribution of precipitation system size, its spatial and temporal pattern, as well as its relationships with precipitation amount, frequency, intensity, and duration. Our results show that large precipitation systems (>10 ^6 km ^2 ) occur more frequently over ocean. Most land areas are dominated by medium-size precipitation systems (10 ^4 –10 ^6 km ^2 ), except that some relatively smaller precipitation systems (<10 ^4 km ^2 ) are dominant over the eastern Pacific, some parts of southern Atlantic the northern Africa, and central Asia. The most apparent seasonal contrast in precipitation system size occur over midlatitude oceans, the southeast United States, and the Amazon Basin. The diurnal contrast of precipitation system size is weaker over the oceans where the latitude is greater than 30°, and stronger over land and tropical oceans. The precipitation system size is highly positively spatial-correlated with precipitation amount, frequency, intensity, and duration. The strongest temporal associations of precipitation system size with precipitation amount, frequency, intensity, and duration on monthly scale occur over the tropics, with correlation coefficients greater than 0.8. This study indicates evident regional differences, which can provide new information to deepen the understanding of local synoptic systems in regional studies.

Keywords

• precipitation system size
• GPM
• IMERG
• geographic distribution