DOPPLER RADAR ECHO FEATURE AND ENVIRONMENTAL CONDITION ANALYSIS OF A MESOSCALE RAIN BELT

By using a single 3830-CC Doppler intensive weather radar data and Micaps objective data, a mesoscale NNE-SSW band echo evolution and environmental condition under southsouthw est air stream around subtropical high were analyzed on August 22, 2002.The results show that the mesoscale band echo is a direct influential system of the mesoscale rain belt and that a warm shear of wind, south-southwest jet flow and anti-wind zone are major radar echo features of the severe precipitation.The south-southwest air stream around subtropical high of fers not only moisture condition, but also heat and dynamical conditions, which are indicated by moist potential vorticity distribution.The band echo and rain belt locate in the zone between barotropic instability and baroclinic stability with a potential instability of negative vorticity circulation in the lower layer.