Effects of Initial-Boundary Conditions on the Simulation of a Supercell Storm

Abstract

To understand the impacts and mechanisms of initial-boundary conditions on the simulation of meso- and micro-scale weather system， a supercell storm episode occurred in the Capital Airport on August 9， 2021.This study simulated by WRF （version 4.3） model using different initial-boundary conditions.Results show that the temporal and spatial structures of synoptic temperature and pressure in FNL， GDAS， and ERA-5 are different， which result in inevitably differences in meteorological elements simulation and supercell storm evolution.Among them， the resolution of FNL data is the lowest， which has poor ability to reproduce the main weather systems and results in rapid decay of the simulated supercell process； the bias of ERA-5 data is smallest in the lower troposphere at 850hPa， which reduces the bias of water vapor convergence simulation at lower atmosphere， and well reproduces the range of supercell.Further investigation indicates that simulation performances are improved when the initial simulation time is closer to the occurrence time of the supercell， indicating that the update cycle of initial-boundary conditions should be consistent with the fast movement and short lifetime of the simulated weather system， to better capture the gravity wave activities.Therefore， the quality of the synoptic-scale initial-boundary conditions play a decisive role in the simulation of meso-scale weather systems， and the meso- and micro-scale characteristics of the weather system determine the prediction success of the mesoscale model.

Keywords

• initial-boundary conditions
• wrf model
• supercell storm
• temporal and spatial structures