南印度洋热带气旋时空特征统计分析

Spatiotemporal Characteristics’ Statistical Analysis of Tropical Cyclones in Southern Indian Ocean

摘要: 本文采用JTWC33年南印度洋热带气旋最佳路径数据集，统计分析不同强度热带气旋时空变化特征。结果表明：33年中南印度洋共生成TC549个，年均16.64个；其中TS生成最多，年均4.76个；其次依次为TY、SuperTY、STS、STY；TD生成频数最少。热带气旋频数逐年变化在10~22个之间，总体呈持平趋势。多数级别热带气旋几乎每年都会生成，近年来级别较强的热带气旋出现频数和比例均明显上升。南印度洋热带气旋主要集中在11月至次年4月，2月最多，较强热带气旋频数增加较晚。南印度洋热带气旋三个比较集中的源地海域为：澳大利亚西北部海面、科克斯群岛至毛里求斯岛一带海面和莫桑比克海峡中部。

Abstract: In this paper, spatiotemporal characteristics of tropical cyclone (TC) during the 33 years are statistically analyzed based on JTWC’s tropical cyclone best path data set in Southern Indian Ocean. The results represent that there are totally 549 TCs during the 33 years in Southern Indian Ocean, and averagely 16.64 TCs every year with 4.76 tropical storms as maximum grade (followed by typhoon tropical cyclone, super tropical cyclone, strong tropical storm and strong tropical cyclone) and tropical depression as the minimum grade. The trend of TC yearly frequency variation is generally invariant, and 10~22 TCs occur per year. Most of TC grades occur every year. Stronger TCs’ yearly frequency is increasing significantly in recent years. In the aspect of monthly frequency variation trend, most TCs occur from November to April, especially in February. Monthly frequency of stronger TC increases later in early autumn. There are three TC source regions in this paper: ocean area of northwest Australia, Cocos Islands, and Mauritius Island.