摘要
该文利用2005—2014年丰都县地面天气、探空数据、NCEP 1°×1°FNL再分析资料等,对丰都地区冰雹、雷暴大风、短时强降水这3类强对流天气特征进行统计分析,得出这3类强对流天气的时空分布特征,并从天气个例出发,利用实况资料对强对流天气的差异进行分析,为强对流天气的预警预报提供参考。得到如下结果:短时强降水通常出现在5—9月,大风通常出现在5—8月,冰雹通常出现南部的七跃山脉和北部的蒋家山和黄草山脉附近[1],2005—2014年间共出现了7次,3—8月均有发生。通过计算3种强对流天气环境场参量,归纳出3种物理量参数的差异:大气可降水量、ΔT500-T850,K指数、抬升指数(LI)、相对湿度、散度场分布等在冰雹、短时强降水和大风天气中有明显的差异,冰雹和短时强降水的ΔT500-T850相差了近5℃,大风天气的值介于冰雹和短时强降水之间。大气可降水量分布上,短时强降水的大气可降水量(PW)平均值为58 mm,比冰雹值大约多了10 mm,比大风值多了14 mm。短时强降水出现时几乎整层都是处于饱和的状态,冰雹和大风天气几乎只在中低层有较饱和的水汽,而高层的相对湿度平均值在40%~50%左右。对流指数方面,K指数和LI指数都很好的指示了强对流天气的发生,K指数在短时强降水发生时其平均值在39.8℃左右,较冰雹和大风分别高1.6℃和3℃。短时强降水出现环流位置大多位于600 hPa以下,而冰雹则在300 hPa左右,大风在400 hPa左右。
The ground weather data,space data,and NCEP 1°×1°data in Fengdu county from 2005—2014 were used to analyze the characteristics of the severe convective weather such as hail,short-time heavy rain and gale in the spatial and temporal distribution.In order to provide the information for the convective warning,the differences of the three strong convective weather phenomena are as followings:the short-time heavy rain usually started from May to September,the gale from March to August,and the hail mainly occurred at the Qiyue mountains in the south and the Jiangjia mountains in the north and Huangcao mountains nearby,which happened 7 times in total between 2005 and 2014.By calculating the environment index of these three weather phenomena,the difference that the distributions of the PWV,ΔT 500-T 850,K index,LI index,relative humidity,and the divergence field are significant,especially the difference ofΔT500-T850 between the hail and the short-time heavy rain reached to 5℃.But the value of the gale was that between the hail and the short-time heavy rain.For the distribution atmosphere,the PWV of short-time heavy rain was 58mm,about 10mm than the hail value and 14mm than the gale value.When the short-time heavy rain started,all layers of the atmosphere were saturated.While the hail and gale were only saturated relatively at the medium-low level,and the relative humidity in the high level was just about 40%~50%。For the convection index,the K and LI indexes could indicate enough the generation of the convection weather.The average of K index in short-time heavy rain was about 39.8℃,which was more than 1.6℃and 3℃respectively of the gale and the hail.The atmospheric circulation of the short-time heavy rain was mainly below 600 hPa,while the hail was around 300 hPa and the gale was around 400 hPa.
作者
武文婧
WU Wenjing(Fengdu Meteorological Bureau,Fengdu 408200,China)
出处
《中低纬山地气象》
2019年第6期41-49,共9页
Mid-low Latitude Mountain Meteorology
基金
重庆市青年基金项目(QNJJ-201712):丰都县强对流天气特征分析
关键词
短时强对流天气
物理量参数
时空分布
short-time severe convection weather
physical index
spatial and temporal distribution
