Increases in the temperature seasonal cycle indicate long-term drying trends in Amazonia

Abstract Earth System Models project a wide range of rainfall changes in the Amazon rainforest, and hence soil moisture evapotranspiration. Hydrological are heterogeneous, meaning local measurements too sparse to constrain projections large-scale hydrological change. Here we show that amplitude temperature seasonal cycle strongly correlated with annual mean evaporative fraction (surface latent heat flux as surface net radiation) changes, across reanalyses Model projections. We find an increase 1 °C is associated reduction up 0.04. The observed (0.4 °C) over last three decades implies drying, determined absence or energy measurements, matches simulations recent past. Additionally, predict further increases, suggesting drying will continue future climate