The Application of LAPS to Hail Cloud Simulation

Local Analysis and Prediction System (LAPS) introduced and localized by Wuhan Institute of Heavy Rain integrates a variety of observations in central China and provides rich information on high-resolution meso-scale analysis field. Several hail weather processes occurred in mountainous region of western Hubei on 27 and 28 July in 2008 are analyzed based on LAPS data. And the hailstorm cloud is simulated with the three-dimensional convective cloud model which is initiated with the output of LAPS and the sounding.The difference between dew point and air temperature of sounding data and LAPS data at 0800 BT 27 July 2008 shows the humidity is higher above the hail location. According to LAPS data from 0800 BT to 1600 BT at the hail location, the temperature profiles show that there is cold air inflow in the upper air, and the differences between dew point and air temperature demonstrate that the humidity increases near the ground and then decreases with the altitude, while increases again in the upper air. LAPS data show the stratification status and wind field over the hail point is more and more favorable for hail formation, reflecting more realistic information than the sounding data at 0800 BT.The simulation results initiated with LAPS data and sounding data at 0800 BT 27 July 2008 are very close, but on 28 July the simulated echo intensity, vertical airflow speed, max wind speed and the amount of hail by LAPS data of the hail location are greater than that by sounding data. The simulation results initiated with LAPS data at 1600 BT 27 July and 1600 BT 28 July in 2008 near the hail time are larger than that at 0800 BT and the simulated amount of accumulated hail by LAPS data at 1600 BT is closer to the observation. It can be concluded that the simulation initiated with LAPS data near the hail time can better reflect the occurrence and development of the hail cloud which occurs in the afternoon. The simulated results of cloud maintenance time, hail intensity and distribution, hail size are consistent with the observation, which can provide a reference for local hail forecast. Results show that the output of LAPS can provide higher temporal and spatial resolution data for the three-dimensional convective cloud model than the sounding observations.The three-dimensional convective cloud model initiated with LAPS data near the hail occurrence time performs well in reproducing characteristics of the occurrence and development of hail cloud. Moreover, it can capture certain details such as several increment processes which are in agreement with the radar observations. Therefore, the model may contribute to warning condition for hail suppression operation and seeding scheme.