Assessment of physical parameterization schemes in WRF over national capital region of India

Abstract

Increase in the extreme weather events around the world has necessitated application of numerical weather prediction (NWP) models to forecast these events and minimize consequences. Application of NWP models requires appropriate selection of physics parameterization options for close representation of atmospheric processes. In this study, the WRF model performance was evaluated for varying physical parameterization of surface processes in simulating meteorology with respect to varying (i) shortwave and longwave radiation schemes, (ii) planetary boundary layer (PBL) and corresponding surface layer (SL) schemes over Delhi NCR. A total of 11 simulation sets were curated with 7 PBL schemes (ACM2, GBM, UW, MYJ, SH, TEMF and BouLac), 4 surface layer schemes (Pleim-Xiu, Revised MM5, Eta and TEMF), 3 shortwave radiation schemes (Dudhia, New Goddard and RRTMG), 3 longwave radiation schemes (RRTM, New Goddard and RRTMG) and 2 land surface models (LSM) (Pleim-Xiu and Noah). Sensitivity experiments are performed at a fine resolution (1 km) with updated LULC input. Based on the sensitivity analysis, it is inferred that the simulation set which works best for the region is TEMF PBL, TEMF SL, Dudhia shortwave radiation, RRTM longwave radiation and Noah LSM schemes. The TEMF PBL scheme is designed as hybrid (local–nonlocal) scheme and thereby, with consideration of both local and nonlocal viewpoints it is noted that the near-surface meteorological parameters are depicted with greater accuracy. To further address the model biases it is important to refine the physical parameterizations schemes in the WRF model or using different bias correction and data assimilation techniques.