Forest Canopy Transpiration: A Key Moderator of Hydroclimate Variability and Extreme Rainfall in the Maritime Continent

This study investigates the interannual variability of evapotranspiration (ET) in the Maritime Continent (MC), focusing on the dynamics behind its minimal fluctuations despite significant changes in precipitation due to the El Niño-Southern Oscillation. We analyze ET components - canopy evaporation (CE), canopy transpiration (CT), and soil evaporation (SE) - and uncover a self-compensating mechanism between CE and CT. During El Niño, increased CT offset decreased CE and SE, maintaining ET's stability. Conversely, La Niña shows an inverse pattern. Additionally, the research examines the impacts of deforestation on extreme precipitation in MC. Deforestation disrupts the ET balance by removing CT's stabilizing effect, amplifying ET variability, and altering precipitation patterns. Our findings propose a new precipitation paradigm in MC under deforestation: "rich-get-richer, poor-get-poorer, and the middle-class-also-get-poorer," marked by increased variability in extreme precipitation events. The study highlights the critical role of MC's forest canopy transpiration in moderating ET variability and its significant influence on the hydroclimatological cycle, especially under deforestation. This intricate interplay between deforestation, ET, and precipitation emphasizes the need to consider both local land use and broader climatic changes in understanding and managing the region's water cycle and extreme climate events.