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Soil Evaporation Stress Determines Soil Moisture‐Evapotranspiration Coupling Strength in Land Surface Modeling
Author(s) -
Dong Jianzhi,
Dirmeyer Paul A.,
Lei Fangni,
Anderson Martha C.,
Holmes Thomas R. H.,
Hain Christopher,
Crow Wade T.
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl090391
Subject(s) - evapotranspiration , environmental science , evaporation , coupling (piping) , soil science , soil texture , stress (linguistics) , potential evaporation , climate model , moisture , atmosphere (unit) , water content , climate change , remote sensing , atmospheric sciences , soil water , geology , meteorology , materials science , geotechnical engineering , ecology , physics , biology , linguistics , philosophy , oceanography , metallurgy
Model‐based estimates of soil moisture (SM)‐evapotranspiration (ET) coupling strength ( ρ ) vary widely and are prone to bias. Here we apply numerical modeling and remote sensing to identify the process‐level source of modeled ρ bias with the goal of improving the fidelity of current Earth system models. Results illustrate that modeled ρ is most strongly determined by soil evaporation ( E ) stress, and (generally positive) ρ modeling bias is attributable to the oversimplification of soil texture impacts on E stress. Based on new remotely sensed estimates of ρ , we demonstrate that removing ρ bias via a single optimized E stress parameter leads to improved ET accuracy and resolves a well‐known modeling bias in the partitioning of ET into E and T. As such, we highlight the importance of the stress function relating E and SM and its central role in regulating land‐atmosphere coupling processes impacting local climate.