Analysis of synoptic situation and environmental parameters of thunderstorm gales in Hainan

In this study we analyzed the intensity, temporal and spatial distribution, circulation situation and environmental parameters of thunderstorm gale during 2014-2018 in Hainan using regional encrypted automatic station data and sounding data at Haikou, combining with ERA-Interim reanalysis data. The results are as follows. (1) The thunderstorm gales in Hainan mainly occurred in the afternoon to evening period from May to August. The maximum gust wind speed was mostly at level 8 or above. (2) The circulation situation of thunderstorm gales could be divided into three patterns: southwest trough, monsoon trough and cold air. The monsoon trough could be divided into South China coastal trough and South China sea trough according to the location of the trough. (3) The southwest trough pattern has the largest unstable energy and small vertical wind shear. Its dry upper-layer and wet lower-layer characteristic was obvious. In the cold air pattern, unstable energy was the minimum and dry upper-layer and wet lower-layer characteristics was obvious. The pattern has the largest vertical wind shear. In the monsoon trough pattern, unstable energy was relatively large and the whole layer was wet, and there was the smallest vertical wind shear. (4) Thunderstorm gales accompanied by short-term heavy rainfall sometimes in monsoon trough. The wind-force in southwest trough was higher than those in other types.