华北冷涡背景下青岛三次混合型对流天气环境场条件对比分析

利用探空观测资料,对比分析华北冷涡背景下青岛三次混合型对流天气过程环境场条件,揭示出现短时强降水、雷暴大风和冰雹天气时的水汽、稳定度和垂直风切变差异特征。分析结果表明:500 hPa上冷涡中心位于42°N的华北冷涡、850 hPa低涡系统和偏南风急流以及地面气旋是这三次混合型对流天气的影响系统;在这三次混合型对流过程中有无雷暴大风天气的环境参数区别比较显著:有雷暴大风表现出了相对较干的中低层和中层存在浅薄湿层的水汽层结,无雷暴大风的则是上干下湿和中层大气干燥的层结特征;稳定度差异决定了对流强度的差异:同时出现短时强降水、雷暴大风和冰雹的对流天气的层结不稳定度最强,表现为较大的850和500 hPa温差(大于30℃)以及较强的0~3 km垂直风切变(大于12 m·s^-1);出现短时强降水和大风的大气层结稳定度最弱,相应的环境参数值也最小;在强不稳定层结和低层水汽充足的条件下,大于12 m·s^-1的0~3 km垂直风切变对青岛地区雷暴大风和冰雹的预报预警有较好的指示意义。

Contrastive Analysis for Environmental Conditions of Three Co-Existence Convective Processes at Qingdao Under the Background of Cold Vortex over North China

In order to reveal the differences of moisture,unstable conditions and wind vector shears in the processes of flash heavy rain,thunderstorm gale and hailstone,comparative analyses on environmental atmospheric variables by using sounding observations at Qingdao are carried out for the three co-existence convective processes under the background of cold vortex over North China.The influence systems are cold vortex over North China with cold center around 42°N at 500 hPa,low value system and southern jet at 850 hPa as well as surface cyclone.It indicates there were significant differences for environmental atmospheric variables with thunderstorm gale or not,that is,shallow wet layer in the middle and dry in the lower layer was the moisture stratification structure with the weather of thunderstorm gale.On the contrary,the moisture stratification was dryer in the middle and wetter in the low layer for the weather without thunderstorm gale.The convective intensity was determined by the atmospheric stability in the course of weather.The strength of unstable stratification was the strongest with larger temperature difference between 850 and 500 hPa(larger than 30℃),stronger vertical wind shear at the height of 0~3 km(larger than 12 m·s^-1)in the process of flash heavy rain,thunderstorm gales and hailstone coexisting.And the strength of unstable stratification was the weakest for the convective weather with flash heavy rain and gales coexisting.Under the condition of strong unstable stratification and abundance moisture in the low layer,the vertical wind shear at the height of 0~3 km had good significance for the warning of thunderstorm gales and hailstone weathers around the region of Qingdao.