1953～2012年间影响浙江的热带气旋大风的气候特征及其影响因素分析

Analyses on the characteristics of violent wind of TCs and the corresponding influence factors in Zhejiang Province from 1953 to 2012

利用1953～2012年热带气旋资料、浙江大风实况资料和地面高空图资料,对60a来影响浙江的热带气旋大风进行统计分析;将热带气旋移动路径分为7种类型进行讨论,分析各种路径的热带气旋所产生极大风速的分布特征和强度特征.结果表明:1953～2012年60 a中影响浙江的热带气旋共有279个,平均每年影响浙江的热带气旋有4.7个,产生8级以上和12级以上大风分别有4.3个和1.9个,造成浙江大风的热带气旋主要发生在7～9月,占80%;登陆热带气旋产生的极大风速与近中心最大风速正相关,且产生的极大风速常比其近中心最大风速大;12级以上大风出现概率较大的依次是登陆浙江沿海、在浙闽边界到厦门之间沿海登陆、近海北上转向、在浙沪边界到鲁辽边界之间沿海登陆的热带气旋.对热带气旋产生大风时的高低空环流形势进行分析,发现副热带高压、大陆高压、地面冷高压常对浙江热带气旋大风有增幅作用.因此,热带气旋大风的预报,除考虑热带气旋自身因素外,也要考虑多系统之间的相互作用.

Tropical cyclones （TCs）data, violent wind data （of Zhejlang Frovmce ）and grouna-baseu mgn aantuue chart data were used in statistics to classify the TCs of the past 60a（ 1953 -2012 ）into seven categories according to their tracks; and TCs of different track types were analyzed for the distribution and intensity characteristics of their maximum instantaneous wind speed. The results show that a total of 279 TCs influenced Zhejiang Province from 1953 to 2012, i.e. an average of 4. 7 TCs each year, including 4. 3 TCs of Beaufort 8 and above and 1.9 TCs of Beaufort 12 and above. 80 percent TCs causing violent winds in Zhejiang occur between July and September each year. The maximum instantaneous wind speed and the maximum 10-minute average wind speed near the center of the landfalling TCs are positively correlated, and the former is greater than the later in most TCs. TCs producing winds with Beaufort 12 and above are more likely the ones landfalling on Zhejiang, then comes the ones landfalling between Zhejiang-Fujian boundary and Xiamen city, the northward-turned TCs over the near sea, and the TCs landfalling between the Zhejiang-Shanghai boundary and the Shandong-Liaoning boundary. Moreover, the horizontalcirculations when the,violent wind occurs in TCs are analyzed in this paper, which reveals that the West Pacific subtropical high, the subtropical mainland high, the cold surface high enhance the violent wind velocity of TCs in most cases. As a conclusion, the forecast of the violent wind of TCs should take into account of both the effect of TCs and the influences of the interactions among multiple weather systems.