江西省春夏季强对流天气气候特征

利用1960—2007年江西省87个地面气象站常规观测资料,对江西冰雹、雷雨大风（风速≥17m/s）和强降水（雨强≥30mm/h）3种强对流天气气候特征进行统计分析。结果表明,冰雹、雷雨大风和短时强降水年平均发生次数分别为13.7、181.4、123.8站次。冰雹和雷雨大风有明显的月际变化,冰雹站次峰值在3—4月,占总数的79.1%。雷雨大风站次有2个峰值,分别在7—8月和4—5月,占总数的44.3%和31.7%,且4月全省10站以上的大范围雷雨大风日数最多。自1990年以后,冰雹和雷雨大风呈逐年减少趋势。短时强降水主要出现在6—8月,占总数的70.3%,大范围短时强降水过程日数8月最多。在地理分布特征上,冰雹丘陵、山区多,平原少,赣东北最少,并有6个冰雹多发区;雷雨大风东多西少,平原和河谷或峡谷地区多山区少,赣西北最少,有5个雷雨大风多发区;短时强降水东多西少,南多北少,有5个高值中心。

CLIMATIC CHARACTERISTICS OF SEVERE CONVECTIVE WEATHER IN SPRING AND SUMMER IN JIANGXI

The routine surface observation data of in Jiangxi for the period of 1960-2007 are used to statistically analyze the climatic characteristics of three kinds of severe convective weather, namely hailstorm, thunderstorm gale （ ≥ 17 m/s ） and short- range severe precipitation （ ≥ 30 mm/h ）. The results show that the average occurrence frequencies of hailstorm, thunderstorm gale and short-range severe precipitation are 13.7, 181.4 and 123.8 per year respectively. Hailstorm and thunderstorm gale vary intermonthly obviously. The peak values of hailstorm occur in March and April, accounting for 79.1% of the total. There are two peak value periods for thunderstorm gale, which are April--May and July--August, with occupying 44.3% and 31.7% of the total respectively. And the thunderstorm gale events with over ten stations happen mostly in April. Moreover, the occurrences of hailstorm and thunderstorm gale have been decreasing gradually since 1990. On the other hand, a majority of short-range severe precipitation happens in June--August, with 70.3% of the total, and the most regional short-range severe precipitation events occur in August. Geographically, hailstorm happens more in rolling ground and mountainous area than in plain, with 6 frequently occurred regions, and the least in northeast Jiangxi. Thunderstorm gale occurs more in plain and valley than in mountainous area, with 5 frequently occurred regions, and the least in northwest Jiangxi. More short-range severe precipitations take place in east and south parts of Jiangxi than in west and north parts of Jiangxi, with 5 peak value areas.