Snow surface temperature update process in Noah land surface model: a modified approach
We have further considered snow surface skin temperature to be different than average snowpack temperature in the energy and water balance calculation of Noah LSM. This was done by adaptation of the Utah Energy Balance (UEB) model (Tarboton and Luce, 1996). Like Noah LSM, the UEB model represents snow in a single snow layer and applies energy balance to compute average snowpack temperature at every time step. However, unlike Noah, within a single snow layer, UEB acknowledges snow surface skin temperature to be different than average snowpack temperature using an equilibrium gradient approach which is based on surface energy balance. Experiments with the modified approach were conducted in several Sierra Nevada SNOw TELemetry (SNOTEL) sites. Four water years – 2002 to 2005 with NLDAS forcing data were used for model inputs. The results show better simulation of snow accumulation and less bias when compared to that of the SNOTEL observation.