Ecosystem Regulated Rainy Season Onset and Drought Variability over Amazonia

Although the influence of rainfall on terrestrial ecosystem has been well established, the influence of ecosystems on rainfall is still debated. Conventional wisdom attributes the onset of rainy season and drought mainly to physical climate variability, while acknowledges that ecosystems can play a secondary role in amplifying or mitigating droughts. This presentation aims to show that terrestrial ecosystems and their interaction with atmospheric variability are instrumental in initiating and regulating rainy season onsets and the development of extreme droughts based on a variety of the observational evidences. Such an influence of ecosystems on rainy season onset not only provides underlying mechanisms for landuse influence on rainfall seasonality and drought variability, but also serves as a potential of drought predictability over the tropical and subtropical continents.