Improve the estimation of sublimation and evaporation from the ground snow surface and frozen soil in WRF

It has been noticed that the WRF model overpredicts surface dew point temperature during the transition periods between winter and spring, and between fall and winter for the areas where the surface is fully or partially covered by snow. The overprediction of the surface dew point temperature is closely linked to the calculation of sublimation and evaporation which are strongly affected by the effective snow surface temperature and latent heat of vaporization and sublimation. In this study, the methods of calculating latent heat of vaporization and sublimation were reviewed, and several sensitivity tests of the WRF model to the effective snow surface temperature were conducted. Modeled latent heat fluxes and dew point temperature were compared with measurements from Brookings, SD. Preliminary results show that the prediction of the surface dew point temperature by WRF can be improved by using the temperature dependent latent heat of vaporization and sublimation.