Dry periods amplify the Amazon and Congo forests' rainfall self-reliance

Moisture recycling is an important source of precipitation in the tropical forests of South America and Africa. Moisture is partly recycled from the tropical forests themselves (forest rainfall self-reliance) and is therefore subject to deforestation, which reduces evaporation. During the dry season, when water is already scarce, a further reduction in precipitation due to decreasing moisture recycling rates could potentially be fatal for already vulnerable ecosystems. It is therefore important to better understand the self-reliance of precipitation in tropical forests. For this reason, we present climatologies of precipitation dependence on evaporation in and from tropical forests using WAM2layers driven by ERA5 data. We find that forest rainfall self-reliance increases during the dry season in both the Amazon and Congo rain forests.