摘要
利用1990—2008年常规观测资料和850hPa、500hPa高空资料,分析了闽西北冰雹的时空分布特征和有利于产生冰雹的天气型。结果表明,闽西北是福建省冰雹多发区,近年来降雹呈明显减少趋势;月变化呈现一大明显单峰(4月)和两小双峰(7月、11月)现象,主要发生时次在14:00—20:00;连续降雹日数以孤立日为主,每次降雹以1～2站次较为多见;11至翌年5月,有利于产生冰雹的天气型(850hPa)为暖切适中型、低涡冷切适中型,冷切适中型和低槽偏东型;冷切偏西和暖切偏北型降雹发生概率较适中型低,较偏南型高;74.1%的雹日伴有低空西南急流,并以急流适中和偏北型居多;大于等于3站次降雹的主导天气形势为暖切适中型、低涡冷切适中型,81.5%伴有低空西南急流;6—9月有利于产生冰雹的天气型(500hPa)为副热带高压边缘型和副热带小高压型,发生较大范围冰雹的可能性小。
Based on the conventional observation and radiosonde data at 850 hPa and 500 hPa from 1990 to 2008, the spatial and temporal features of hailing days and atmospheric circulation patterns over Fujian are analyzed. The results show that hail disasters occurred frequently in Northwest Fujian, and there were a decreasing trend in recent years. The monthly change of hail events presents a typical multiplepeak pattern with the big peak in April and two small peaks in July and November. Hails occurred mainly from 14：00 to 20：00. The hail events usually occurred solitarily, and the affected stations were less than three. From November to next May, the main circulation patterns at 850 hPa favorable for hail generation include “moderate warm shear,” “moderate vortex and cold shear,” “moderate cold shear,” and “eastward deflection trough.” The hailfalling probabilities in the pattern of “westslanting cold shear” and “northwardslanting warm shear” were smaller than those in “moderate vortex and shear,” and greater than that in “southslanting shear.” The 74.1% of hail days were associated with a strong lowlevel southwest jet, mostly “moderate jet” or “northslanting jet.” The main weather patterns affected three or more were “moderate warm shear,” “moderate vortex and cold shear.” The 81.5% of hail events were associated with the strong lowlevel southwest jet. From June to September, the circulation patterns at 500hPa favorable for hails were “peripheraltype subtropical high” and “small subtropical high,”and the probability of largescale hail weather was small.
出处
《气象科技》
北大核心
2011年第6期785-790,共6页
Meteorological Science and Technology
基金
福建省科技厅重点项目(2009Y0006)
福建省气象局课题(200806)资助
关键词
冰雹
天气形势
时空特征
hail circulation pattern spatialtemporal characteristic
