| Abstrakt: |
A thunderstorm is an extreme weather event that has become one of the most alarming disasters in Bangladesh because of its frequent occurrence and devastation in recent years. This study investigates the physical and dynamical characteristics of thunderstorms and their associated lightning over Bangladesh using the Weather Research and Forecasting (WRF) model. Two thunderstorm cases that occurred over central and south-western regions of Bangladesh on April 25, 2018, and May 11, 2018, have been simulated using three domains of 9-km, 3-km, and 1-km horizontal grid sizes. The simulated results are then compared with the observations from the Bangladesh Meteorological Department (BMD), University of Wyoming, and Meteorological & Oceanographic Satellite Data Archival Centre (MOSDAC). Convective Available Potential Energy (CAPE) and Total Total Index (TTI) are analyzed and found to be 1500 J/kg and 48°C, respectively, 10 hours before both events. Vertical wind has been found around 4 m/s before the event. Ice and graupel mixing ratios are found at very high concentrations at the cloud center. Lightning Potential Index (LPI) has been calculated using mixing ratios of different hydrometeors and vertical wind. The LPI is found to be 0.2 to 0.8 J/kg for the two cases. For estimating the electric field inside the thunderclouds, an algorithm that considers ice and graupel as leading charge carriers has been used. The electric field is found to be 70 kV/m at an altitude of 8 km for the first case and −125 kV/m at an altitude of 7 km for the second case. All the parameters are found favorable for the initiation of thunderstorms and lightning occurrence. It indicates that the algorithm suggested in this study can be used to predict high-impact weather events in Bangladesh. [ABSTRACT FROM AUTHOR] |
Full text from SpringerLink