Wang Yi, Zheng Yuanyuan, Zhuang Xiaoran, Zhang Jing, Mu Ruiqi, Sun Kangyuan. 2022. Statistical analysis of the structural characteristics of typical downbursts in Jiangsu province,China. Acta Meteorologica Sinica, 80(4):592-603. DOI: 10.11676/qxxb2022.023
Citation: Wang Yi, Zheng Yuanyuan, Zhuang Xiaoran, Zhang Jing, Mu Ruiqi, Sun Kangyuan. 2022. Statistical analysis of the structural characteristics of typical downbursts in Jiangsu province,China. Acta Meteorologica Sinica, 80(4):592-603. DOI: 10.11676/qxxb2022.023

Statistical analysis of the structural characteristics of typical downbursts in Jiangsu province,China

  • 19 typical downburst events in Jiangsu province from 2007 to 2018 are statistically analyzed using conventional observations, radar data, automatic meteorological station (AMS) data and ERA5 reanalysis product to reveal their structural characteristics. The results show high frequency of downburst in the north of Jiangsu and low frequency in the south, while wet downbursts account for most of the cases. July is the month with high downburst occurrences. The downburst caused by an isolated storm is featured by weak synoptic-scale forcing, wet low levels and dry mid- to high levels and slow storm movement. However, the downburst embedded in a squall line is featured by strong synoptic-scale forcing and fast storm movement. The ground temperature changes drastically during the downburst, and the temperature drop is accompanied by significant increase in wind speed. By statistics, the average vertical lapse rate of temperature is 6.8℃/km, which can ensure the maintenance of negative buoyancy. The dry and cold air is entrained into the storm by the mid-level convergent airflow and further strengthens the downdraft, which helps maintain and strengthen the downburst. In the initial stage, strong reflectivity and mid-level radial convergence appear 20—30 min prior to the downburst. In the mature stage, the height of the strong reflectivity core significantly descends, and the lower layer presents a divergence structure.
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