关键词: 副热带高压, 暴雨, 风廓线, 逆风区, 副热带高压, 暴雨, 风廓线, 逆风区

Abstract:  Based on the basic reflectivity, basic radial velocity and wind profile data from Doppler radar, two heavy rain processes in Dandong area on August 19 and 20, 2010 were analyzed, and their weather situations and radar echo characteristics were discussed. The results indicate that the forces of southward cold air and warm wet air of the rear subtropical high  are compatible  when Dandong is located within subtropical high or near the margin, so it comes into being a typical heavy rain model in Dandong. The VWP (vertical wind profile) has a water vapor accumulation process during the prophase of precipitation, and it shows that upper level jet stream appears and upper momentum transports downward during the short-time heavy rain of two processes. The downward transportation of upper momentum makes lower level jet stream strengthened and the lower level converges, so rain intensity increases obviously. An echo strip with 40 dBz is formed in the precipitation echo areas of two processes, and the echo moving direction is consistent with the echo axial direction, which makes precipitation time prolonged and rainfall intensity increased. The occurrence time of inverse wind area is corresponding with that of the short-time strong rainfall. The corresponding relationship between the location of strong rainfall and strong echo area suggests that the larger the thickness of inverse wind area is, the stronger the corresponding reflectivity factor is, and so rainfall intensity is also strong.

Key words: Subtropical high, Rainstorm, Wind Profile, Adverse wind area, Subtropical high, Rainstorm, Wind profile, Inverse wind area