Variations in the Diurnal Cycle of Precipitation and Its Changes with Distance from Shore over Two Contrasting Regions as Observed by IMERG, ERA5, and Spaceborne Ku Radar

Abstract The diurnal cycle of precipitation is highly regional and typically a product multiple competing, localized effects. in regions such as the Amazon Maritime Continent are particular interest, due to complex coastal terrain high spatial temporal resolution provided by Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (GPM) mission (IMERG) dataset used this study examine fine-scale features these regions. Using an 18-yr (2000–18) record IMERG observations, semidiurnal phase amplitude calculated using fast Fourier transform (FFT) method on half-hourly averaged at 0.1° × 0.1°. Clear patterns propagation with distance from shore shown over both regions, exhibiting strong dependence coastline. Semidiurnal cycles generally weaker than except some isolated locations. Similar analysis also conducted ERA5 reanalysis data order evaluate model’s representation cycle. model captures broadscale variability but does not capture all nor exact timing that observed IMERG. Comparisons made long-record Ku radar created combining Tropical Rainfall Measuring Mission (TRMM) GPM thus providing additional point comparison peak, since can be different, even between observational datasets.