Penman-Monteith Evapotranspiration under Soil Moisture Limiting Conditions across California

Abstract:

In arid and semi-arid regions soil moisture often limits the flux of water to meet the atmospheric evapotranspiration (ET) demand. Potentially drier conditions and more variable precipitation and snow in California create a need to better understand how this reservoir limits ET across the state. The upcoming Soil Moisture Active Passive (SMAP) mission’s surface and root zone soil moisture data will provide additional information to force observation based ET models at spatial scales ranging from 3-36 km². To support application of SMAP data to ET modeling we investigate the role of soil moisture within the Penman-Monteith representation at FLUXNET and agricultural sites across California. We present findings on actual ET under soil moisture limiting conditions that do not violate assumptions within this modeling framework.