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Global characterization of surface soil moisture drydowns
Author(s) -
McColl Kaighin A.,
Wang Wei,
Peng Bin,
Akbar Ruzbeh,
Short Gianotti Daniel J.,
Lu Hui,
Pan Ming,
Entekhabi Dara
Publication year - 2017
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 - 10.1002/2017gl072819
Subject(s) - evapotranspiration , environmental science , water content , surface runoff , infiltration (hvac) , precipitation , moisture , arid , soil water , climate change , water balance , hydrology (agriculture) , climate model , climatology , soil science , atmospheric sciences , meteorology , geology , geography , geotechnical engineering , ecology , paleontology , oceanography , biology
Loss terms in the land water budget (including drainage, runoff, and evapotranspiration) are encoded in the shape of soil moisture “drydowns”: the soil moisture time series directly following a precipitation event, during which the infiltration input is zero. The rate at which drydowns occur—here characterized by the exponential decay time scale τ —is directly related to the shape of the loss function and is a key characteristic of global weather and climate models. In this study, we use 1 year of surface soil moisture observations from NASA's Soil Moisture Active Passive mission to characterize τ globally. Consistent with physical reasoning, the observations show that τ is lower in regions with sandier soils, and in regions that are more arid. To our knowledge, these are the first global estimates of τ —based on observations alone—at scales relevant to weather and climate models.