Influence of various land surface parameterization schemes on the simulation of Western Disturbances

Five western disturbances (WDs) are simulated using the National Center for Atmospheric Research (NCAR) Weather Research and Forecasting (WRF) model with different land surface parameterization (LSP) schemes. The LSP schemes used in this study are thermal diffusion, Noah and rapid update cycle (RUC). The spatial distribution and area averaged values of 24 h accumulated rainfall simulated by the model using above LSP schemes are compared with corresponding Tropical Rainfall Measuring Mission (TRMM) observed values. The model simulated rainfall is also compared with those obtained from India Meteorological Department (IMD) station observations. Area averaged root mean square error (RMSE) in rainfall obtained from the three LSP schemes for the five cases are also compared against those in TRMM. Results show that the rainfall obtained using the RUC LSP scheme is closer to the observed values in comparison to those obtained in the thermal diffusion and Noah LSP schemes. It is clear from the results that circulation features and precipitation amounts obtained by the model are sensitive to LSP schemes. Compared to the verification analysis, the wind patterns at 850, 500 and 200 hPa are simulated by the model with reasonable accuracy. The relative humidity and mean sea level pressure are also well simulated by the model when RUC LSP is used.