Seasonal Changes of Diurnal Rainfall Over New Capital City of Indonesia from High-Resolution Satellite Data

Diurnal cycles are the main factor determining the rain pattern in the Indonesian maritime continent. In-depth research regarding diurnal rainfall patterns is very important for strategic planning of urban area development. This study analyzes the influence of the season on diurnal rainfall patterns in the New Capital City of Indonesia (IKN) based on Integrated Multi-satellite Retrievals for GPM (IMERG) data from January 2001 to April 2019 with a data resolution of 0.1°–30 min. Analysis of the influence of the season on the diurnal pattern was observed based on the parameters of precipitation amount (PA), precipitation frequency (PF), and precipitation intensity (PI). An increase in PA and PF values was observed from November to May, while a decrease in PA and PF values was observed from June to October. The highest increases in PA and PF values were observed in March, April, and December, which are consistent with the peak of seasonal rainfall in IKN. The dominant increase in PA and PF values in that month was caused by an increase in the percentage of occurrence of long-duration (> 6 h) rainfall. On the other hand, an increase in the value of PI shows a non-uniform pattern following the season which indicates the season factor is not the main triggering factor of PI. Furthermore, the seasonal factor also affects the time of the diurnal rain peak in IKN. Peak rainfall is observed during July–August [1300–1400 local solar time (LST)] compared to other months (1500–1600 LST). The earlier diurnal peak time of rainfall is a result of reduced cloud cover during July–August, which intensifies solar insolation and accelerates the attainment of thermal contrast. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd