Reply on RC2

TL;DR: This article disentangled the relative contributions of precipitation, net radiation, air temperature, VPD, and wind speed on the annual evapotranspiration linear trend using an advanced separation method that considers the Budyko framework.

Abstract: <strong class="journal-contentHeaderColor">Abstract.</strong> Actual evapotranspiration (ET) is an essential variable in the hydrological process, linking carbon, water, and energy cycles. Global ET has significantly changed in the warming climate. Although the increasing vapor pressure deficit (VPD) enhances atmospheric water demand due to global warming, it remains unclear how the dynamics of ET are affected. In this study, using multiple datasets, we disentangled the relative contributions of precipitation, net radiation, air temperature (<span class="inline-formula"><i>T</i>₁</span>), VPD, and wind speed on the annual ET linear trend using an advanced separation method that considers the Budyko framework. We found that the precipitation variability dominantly controls global ET in the dry climates, while the net radiation has substantial control over ET in the tropical regions, and VPD impacts ET trends in the boreal mid-latitude climate. The critical role of VPD in controlling ET trends is particularly emphasized due to its influence in controlling the carbon–water–energy cycle.