An Atlantic influence on evapotranspiration in the Orinoco and Amazon basins

作者：Nicolás Duque-Gardeazábal, Andrew R. Friedman, Stefan Brönnimann · 发表于：Hydrology and earth system sciences · 年份：2025 · DOI：10.5194/hess-29-3277-2025 · 被引用次数：3 · 研究领域：Hydrology and Watershed Management Studies、Plant Water Relations and Carbon Dynamics、Climate variability and models

Abstract. Tropical South America's hydroclimate is influenced by ocean–atmospheric variability modes (drivers of climate variability). It is still not known which physical mechanisms teleconnect the Atlantic modes of variability with South America's soil moisture, net radiation, and terrestrial evaporation (evapotranspiration). Understanding these mechanisms is essential to predict the response of ecosystems. This study uses composites of reanalysis and satellite data to identify the processes linking land–surface anomalies and ocean–atmospheric modes. It estimates the control soil moisture and net radiation impose on evapotranspiration (categorised as water- or energy-limited regimes). It shows that these two local controllers of evapotranspiration are influenced by the position of the Intertropical Convergence Zone (ITCZ). However, the evapotranspiration anomalies are driven by the phase of each climate mode, which alter water and radiation availability. The Atlantic Meridional Mode (AMM) generates cross-equatorial wind anomalies that affect moisture convergence, which in turn modify the cloud cover, precipitation, soil moisture, radiation availability, and hence evapotranspiration. The anomalies have important geographical differences depending on the season analysed; they migrate from the east in austral autumn towards the central Amazon and western Orinoco in austral spring. The Atlantic Niño Equatorial mode (Atl3) affects evapotranspiration in the Guianas and eastern Or...