Land-atmosphere interactions over the Indonesian Maritime Continent

Abstract

The “Maritime Continent” (MC) is the largest archipelago in the tropical region, consisting of over 22,000 islands and inhabited by more than 400 million people. This region has a significant impact on global atmospheric circulation, especially during the strong interannual climate variability events, such as El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) events, which can have far-reaching effects on global climate patterns. The region is also affected by seasonal variations, such as monsoons (Australian and Indian Monsoons), intraseasonal variations, such as the Madden-Julian Oscillation (MJO), and diurnal variations due to Sea Breeze Circulation (SBC). These multiscale variabilities influence the livelihood of the inhabitant through weather extremes and affect the practice and sustainability of agriculture in the region, which produces globally essential crops and agricultural commodities. Unfortunately, state-of-the-art global climate and weather prediction models suffer from persistent systematic bias in precipitation and limited prediction skills over the MC, also known as the “MC prediction barrier.” Additionally, the MC often disrupts the propagation of MJO, also called the “MC barrier effect.” Furthermore, the monsoon transition and onset over the region are challenging to precisely predict due to the “false onset,” which affects the planting time of the primary crops, eventually threatening food security. Recent studies hint that land surface properties might contribute to these problems. This dissertation investigates the role of land-atmosphere interactions over the Indonesian Maritime Continent. Specifically, the study explores the contribution of land-atmosphere feedback to the diurnal cycle of precipitation over the coastal regions of the Maritime Continent. This study also examines the role of land-atmosphere interactions in MJO propagation across the MC. Finally, this study investigates how land-atmosphere feedback modulates the onset of the wet season in the region during the years without significant large-scale circulations. By pursuing these lines of inquiry, the dissertation aims to enhance our understanding of the complex interactions between land and atmosphere, increase resilience to the impacts of climate variability, and improve food security for the millions of people living on the Maritime Continent.