Evaluation of albedo schemes in WRF coupled with Noah-MP on the Parlung No. 4 Glacier against in-situ observations

Meteorological variables (e.g. air temperature (T2), radiation flux and precipitation) determine the evolution of glacier mass and characteristics. Observations of these variables are not available at adequate spatial coverage and temporal / spatial resolution over the Tibetan Plateau. This study focuses on evaluating the performance of albedo parameterization scheme in WRF coupled with Noah-MP in terms of glacio-meteorological variables, by conducting sensitivity experiments on Parlung No. 4 Glacier in ablation season in 2016. The control experiment (CTL) uses the model’s default albedo scheme and unrealistic surface type, while sensitivity experiments apply the default albedo scheme (Sens1) and the modified scheme (Sens2) in ice surface. The key results are as follows. First, all experiments yield similar T2 diurnal patterns to the observations and realistic land-use type considerably reduces model warm bias on the glacier. The RMSE of T2 decreases by 1 °C with an improvement of 37 % by sensitivity experiment estimates. Second, Sens1 keeps rather high albedo value of 0.68 causing net shortwave radiation and net radiation apparent underestimation, while Sens2 holds mean albedo value of 0.35 close to observations contributing to relieve net shortwave radiation and net radiation underestimation. Thirdly, compared with Sens1 estimates, more energy from Sens2 is used to heat ice surface resulting in high ground heat flux (182 W m^-2), ice melt and liquid water content increase more quickly and preferentially. Our study confirms the ability of WRF model in reproducing glacio-meteorological variables as long as a reasonable albedo parameterization scheme is applied, and provides a theoretical reference for researchers committed to further improving the surface albedo scheme.