The maritime continent’s rainforests modulate the local interannual evapotranspiration variability

Abstract

The interannual variation of evapotranspiration in tropical rainforests is thought to be small, despite the variability of precipitation. Here we investigated the cause of this phenomenon in the Maritime Continent using observations, reanalysis data and model simulations. We find that evapotranspiration’s interannual variation is dampened by the self-compensating mechanism of canopy evaporation and transpiration. During El Niño, when precipitation is lower than climatology, canopy evaporation decreases due to less interception, while canopy transpiration increases in response to increased incoming solar radiation, resulting in a compensating effect and a small interannual variation of evapotranspiration. Deforestation, however, eliminates transpiration’s dampening effect and, thus, amplifies the interannual variation of evapotranspiration significantly. This increase in evapotranspiration’s interannual variation due to deforestation further affect the local hydrological cycle, resulting in decreased interannual variation of precipitation. The results highlight the impacts of deforestation and emphasize the critical role of tropical rainforests in the hydroclimatological cycle.