Diurnal cycle of rainfall and convection over the Maritime Continent using TRMM and ISCCP

摘要

This study investigates the diurnal cycle of rainfall, convection, and precipitation features (PFs) over the Maritime Continent (MC). The study uses Tropical Rainfall Measuring Missions (TRMM) Multi-satellite Precipitation Analysis (TMPA; product 3b42), TRMM PFs, and convective classifications from the International Satellite Cloud Climatology Project (ISCCP) data. Together, these satellites dataset paint a comprehensive picture of the diurnal cycle of rainfall and convection over the MC consistent with past research. Isolated convection initiates around midday over the higher terrain of the large islands (Java, Borneo, and Papua New Guinea). The convection becomes more organized through the afternoon and evening, leading to peak rainfall over the islands around 1800-2100 local standard time (LST). Over the next few hours, some of that rainfall transitions to stratiform rain over land. The convection then propagates offshore overnight with rainfall peaking along the coast around 0300-0600 LST and then over ocean around 0600-0900 LST. ISCCP data suggests that the overnight and early morning convection is more associated with isolated convective cells than the remnants of mesoscale convective systems. The coastal and oceanic diurnal ranges also seem to be larger in stratiform rainfall, in contrast to land where convective rainfall dominates. Seasonally the diurnal variation of rainfall, convection, and PFs over the region have greater amplitude during DJF (December, January, and February) than JJA (June, July, and August). Given the MC's critical role in the global climate, examining variations in these cycles with respect to the Madden-Julian Oscillation and equatorial waves may ultimately lead to improved subseasonal weather forecasts.