Global gray-sky dT: the inverse of the surface psychrometric constant parameter in the SSEBop evapotranspiration model
Dates
Creation
2022-01
Publication Date
2022-04-06
Citation
Kagone, S., and Senay, G.B., 2022, Global gray-sky dT: the inverse of the surface psychrometric constant parameter in the SSEBop evapotranspiration model: U.S. Geological Survey data release, https://doi.org/10.5066/P9JBW6R9.
Summary
The surface psychrometric constant (spc) is a key model parameter in actual evapotranspiration modeling using the Operational Simplified Surface Energy Balance (SSEBop) model for establishing model boundary limits for the dry/bare and wet/vegetated surface conditions. The inverse of the constant (1/spc) represents the temperature difference (dT) between the bare/dry surface and the air temperature at the canopy level. The main output of the SSEBop model is an ET fraction (0-1) and, when combined with reference (“maximum”) ET, produces an actual ET estimate from satellite-observed land surface temperature. This dT is determined using net radiation inputs under gray-sky radiations from the ERA-5 datasets, i.e., Surface Solar Radiation [...]
Summary
The surface psychrometric constant (spc) is a key model parameter in actual evapotranspiration modeling using the Operational Simplified Surface Energy Balance (SSEBop) model for establishing model boundary limits for the dry/bare and wet/vegetated surface conditions. The inverse of the constant (1/spc) represents the temperature difference (dT) between the bare/dry surface and the air temperature at the canopy level. The main output of the SSEBop model is an ET fraction (0-1) and, when combined with reference (“maximum”) ET, produces an actual ET estimate from satellite-observed land surface temperature. This dT is determined using net radiation inputs under gray-sky radiations from the ERA-5 datasets, i.e., Surface Solar Radiation Downwards instead of clear-sky assumptions used for the previous dT versions. The dT estimates are adjusted for elevation effects using established equations.
