A satellite-based perspective of convective systems over the Maritime Continent

Abstract:

Data from TRMM, the A-Train satellites, and the Worldwide Lightning Location Network (WWLLN) have been used to study extreme weather throughout low latitudes, from deep convection over the Himalayas to oceanic mesoscale systems associated with the MJO. This study presents a more in-depth examination of convection over the Maritime Continent (Indonesia and Malaysia). During November to February, this area is the rainiest regional climate on Earth, thus constituting one of the atmosphere’s primary heat sources. On multiple temporal and spatial scales, it is a complex region with clouds and precipitation having both oceanic and orographic influence. The November-February season encompasses both the eastward propagation of the MJO through this region and rainfall associated with the Asian-Australian monsoon. More specifically, the precipitation in this region is strongly modulated by MJO phases, pulsations of the monsoon, and the powerful diurnal effects of the islands and ocean. Through a feature-based analysis of convective and stratiform components of storms, the evolution of precipitating clouds in this region will be described using data from the November-February time period over multiple years. This analysis leads to an increased understanding of the characteristics of convection associated with the intraseasonal and diurnal variability during these months over the Maritime Continent. Previous work using A-Train data noted the prevalence of smaller separated MCSs over the region during the locally active phase of the MJO, and WWLLN data have shown a peak in lightning density as convection becomes deeper and more numerous leading up to this active period. By applying the analysis of the TRMM data in addition to the A-Train and WWLLN datasets, the relative roles of convective and stratiform components of MCSs to the behavior of convection can be determined during the MJO and monsoonal maxima of rainfall over the Maritime Continent.