Evaluation of WRF land surface schemes in land-atmosphere exchange simulations over grassland in Southeast Tibet

Abstract

Abstract Land surface schemes (LSSs) evaluation is essentially important for land-atmosphere energy exchange simulation over the Tibetan Plateau (TP), especially over the Southeast Tibet, where the atmospheric systems of the TP and South Asia interact most. In May 20–July 9, 2013, an observation was conducted over the grassland in the Southeast Tibet, with radiation, sensible, latent and ground heat fluxes measured. Based on the observation data, all seven WRF (the Weather Research and Forecasting Model) coupled LSSs (SLAB, Noah, RUC, Noah-MP, CLM, PX, SSiB) were assessed. All the LSSs can successfully reproduce the diurnal variation of land-atmosphere heat transfer but with amplitude differences from observations. The LSSs also reproduced the variations of land-atmosphere exchange processes under different synoptic situations, especially at the South Asian summer monsoon (SASM) south and north phases. However, large magnitude differences exist within the LSSs simulations in comparison with the observations, which complicated our scheme evaluations and optimal LSSs selections for the Southeast Tibet. Further quantitative studies revealed that the WRF-Noah scheme performed the best among all seven LSSs in retrieving the land-atmosphere heat transfer, partly due to the its most successful surface temperature simulation. Our results suggest that the WRF-Noah scheme should be applied for future land-atmosphere exchange simulations over the Southeast Tibet.