Numerical study of the dynamical mechanism of inertial gravity waves in hail storm process
一次冰雹过程的惯性重力波观测及数值模拟

Gravity waves were observed in a hail storm process on 11 April 1998 in Puding County of Guizhou Province by using very sensitive microbarovariograph. And this process is simulated by using the mesoscale numerical model of WRF and the results of the simulation are analyzed by using Morlet wavelet method. The result shows the characteristics of the spatial-temporal distribution of Inertial Gravity Waves (IGWs). In addition, the factors influencing IGWs and weather system, and the dynamic mechanism of IGWs are studied in this paper. The IGWs with short period are strengthened in each 1~4 hour before the hail storm. The results of the simulation show that some IGWs with short period are generated before near the hail storm below the 3 km altitude. In them the long ones are generated early and last longer, and the others are later and last shorter. At the low altitude, the turbulent convection is generated and strengthened by the strong low jets and shears, and the new IGWs with 80~200 min period are excited by the turbulent convection. The IGWs with short period are easier to propagate vertically, while the long ones tend to propagate horizontally. The period of IGWs with long period is obviously shortened after the hail storm and the IGWs are strengthened along with the altitude. The IGWs over the highest mountain usually are the strongest.