SEBALIGEE v2: Global Evapotranspiration Estimation Replacing Hot/Cold
Pixels with Machine Learning
Abstract
An open source computer algorithm, the Surface Energy Balance Algorithm
for Land-Improved (SEBALI), was designed to estimate actual
evapotranspiration (ET) at a basin level. In this study, we build on
later versions of SEBALI/SEBALIGEE to estimate ET at a 30-m resolution
for any scale application using advanced machine learning approaches
(SEBALIGEE v2). We evaluate the monthly ET estimated from the new
algorithm across several fluxnet sites in US, China, Italy, Belgium,
Germany, and France, yielding an Absolute Mean Error (AME) of 0.41
mm/day versus 0.48 mm/day in the original SEBALIGEE. Analyses of the ET
in the US indicate that the annual wheat ET decreases significantly
between 2013 and 2021 (p < 0.05), accompanied by a significant
air temperature increase. Net solar radiation is found to be the most
influencing factor on ET of corn and soybeans with R2
values of ~0.72.