Controls on surface soil drying rates observed by SMAP and simulated by the Noah land surface model
| Autor: | Ben Livneh, P. J. Shellito, Eric E. Small |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
lcsh:GE1-350
010504 meteorology & atmospheric sciences Moisture Soil texture lcsh:T 0208 environmental biotechnology Evaporation lcsh:Geography. Anthropology. Recreation Soil science 02 engineering and technology Vegetation 01 natural sciences lcsh:Technology lcsh:TD1-1066 020801 environmental engineering lcsh:G Soil water Potential evaporation Environmental science Precipitation lcsh:Environmental technology. Sanitary engineering Water content lcsh:Environmental sciences 0105 earth and related environmental sciences |
| Zdroj: | Hydrology and Earth System Sciences, Vol 22, Pp 1649-1663 (2018) |
| ISSN: | 1607-7938 1027-5606 |
| Popis: | Drydown periods that follow precipitation events provide an opportunity to assess controls on soil evaporation on a continental scale. We use SMAP (Soil Moisture Active Passive) observations and Noah simulations from drydown periods to quantify the role of soil moisture, potential evaporation, vegetation cover, and soil texture on soil drying rates. Rates are determined using finite differences over intervals of 1 to 3 days. In the Noah model, the drying rates are a good approximation of direct soil evaporation rates, and our work suggests that SMAP-observed drying is also predominantly affected by direct soil evaporation. Data cover the domain of the North American Land Data Assimilation System Phase 2 and span the first 1.8 years of SMAP's operation. Drying of surface soil moisture observed by SMAP is faster than that simulated by Noah. SMAP drying is fastest when surface soil moisture levels are high, potential evaporation is high, and when vegetation cover is low. Soil texture plays a minor role in SMAP drying rates. Noah simulations show similar responses to soil moisture and potential evaporation, but vegetation has a minimal effect and soil texture has a much larger effect compared to SMAP. When drying rates are normalized by potential evaporation, SMAP observations and Noah simulations both show that increases in vegetation cover lead to decreases in evaporative efficiency from the surface soil. However, the magnitude of this effect simulated by Noah is much weaker than that determined from SMAP observations. |
| Databáze: | OpenAIRE |
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