Recent global decline in rainfall interception loss due to altered rainfall regimes

Evaporative loss of interception (Ei) is the first process occurring during rainfall, yet its role in large-scale surface water balance has been largely underexplored. This study shows that Ei can be inferred from flux tower evapotranspiration measurements using physics-informed hybrid machine learning models. Forced by satellite and reanalysis data, this framework provides an observationally constrained estimate of Ei, which is on average 84.1 ± 1.8 mm per year globally (2000–2020). Rainfall frequency regulates long-term average Ei changes, and rainfall intensity determines the fraction of Ei in gross precipitation (Ei/P). Less frequent and more intense rain events since 2000 have driven a global decline in Ei (and Ei/P) by 4.9% (6.7%), suggesting that ongoing rainfall changes favor more soil moisture and runoff, benefiting ecosystem functions but increasing flood risks.

Xu Lian, Wenli Zhao, Pierre Gentine