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Global observational diagnosis of soil moisture control on the land surface energy balance
Author(s) -
GallegoElvira Belen,
Taylor Christopher M.,
Harris Phil P.,
Ghent Darren,
Veal Karen L.,
Folwell Sonja S.
Publication year - 2016
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 - 10.1002/2016gl068178
Subject(s) - environmental science , vegetation (pathology) , atmosphere (unit) , climatology , water balance , sensible heat , water content , atmospheric sciences , moisture , latent heat , climate change , water cycle , hydrology (agriculture) , meteorology , geology , medicine , ecology , oceanography , physics , geotechnical engineering , pathology , biology
Abstract An understanding of where and how strongly the surface energy budget is constrained by soil moisture is hindered by a lack of large‐scale observations, and this contributes to uncertainty in climate models. Here we present a new approach combining satellite observations of land surface temperature and rainfall. We derive a Relative Warming Rate (RWR) diagnostic, which is a measure of how rapidly the land warms relative to the overlying atmosphere during 10 day dry spells. In our dry spell composites, 73% of the land surface between 60°S and 60°N warms faster than the atmosphere, indicating water‐stressed conditions, and increases in sensible heat. Higher RWRs are found for shorter vegetation and bare soil than for tall, deep‐rooted vegetation, due to differences in aerodynamic and hydrological properties. We show how the variation of RWR with antecedent rainfall helps to identify different evaporative regimes in the major nonpolar climate zones.