东南极海冰异常与中国夏季洪涝

ON THE RELATIONSHIP BETWEEN THE ABNORMAL VARIATION OF THE EAST ANTARCTIC SEA ICE AND THE SUMMER RAINFALL IN CHINA

本文分析了东南极（0—120°E）海冰净冰面积指数距平值的异常变化（1973－1989）分别与中国160个站夏季（5—8月）降水的耦合交叉领先及滞后48个月的相关强度时间序列和空间场的分布特征。发现东南极海冰变化异常与否和中国的降水有以下密切关系。1．在东南极海冰由夏过渡到冬半年的过渡季节3月份，海冰的迅速增长与中国5周长江以南，南岭以北的东南亚亚热带湿润气候雨区（Ⅱa）［3］有极密切的关系。当海冰异常多或少时，该区的月降水将异常多或少，最大相关系数在永安站达0．76，是反映在我国东亚季风强弱早晚的一个重要标志。自有海冰资料以来（1973），1973年3月是近30年来冰情最严重的一年，而Ⅱa区也是建国以来5月特大洪涝的一年。2．我国夏季降水是东亚季风和印度季风及西风带强弱的综合反映，夏季降水又是后期东南板初夏（12月）海冰强弱的重要标志，这是关系到我国南极考察的重要季节，冰情预报极为关键。3.东南极海冰以超前1－3年的时间与我国降水有极其重要相关期，是研究我国气候文化的重要依据之一。4．东南极海冰有先于澳大利亚冷高2－3个月的极密切的关系。澳大利亚冷高是反映东亚季风的重要标志之一，则东南极海冰也同样是重要先兆依据。

In this paper we discribe the characteristics of the time scries and frild distributions of the coupling cross corrclation intensity of the anomaly of the net sea ice area index in East Antarctic (1973-1989) with the summer (from May to August) rainfall amount at one hundred and sixty Chinese meteorological stations with the sea ice adyancing or lagging the rainfall fourtyeight months. It is foud that there are some close relations between the abnormal varition of the East Antarctic sea ice and the summer rainfall in China as follows.1. The rapid formation of the East Antarctic sea ice in March (a transitional period from summer to winter in the southern hemisphere) is closely related to the rainfall in May in the East Asia subtropical rain zone (south of the Yangzi riyer and north of the Naniing mountains) which is designated as region Ⅱa. If the sea ice is unusually severe or light in Marth, the rainfall in region Ⅱa will be correspondingly tinusually high or low later in May. The maximum correlation coefficient is 0.76 at Yongan station, which is an important indicator for the intensity and the starting time of the East Asia monsoon in China. In March 1973 the sea ice condition was the seyerest of the same months from 1973 to 1989 and so was the rainfall in region Ⅱa in May of that year since 1949.2. Summer rainfall in China is the comprehensive reflection of the intensities of the East Asia monsoon, the lndia monsoon and the westerly belt. It is also an important indicator for the successive sea ice in early summer in the southern hemisphere. To forecast the summer sea ice condition is yery important for the Chinese Antarctic Expedition.3. There is a high correlation between the rainfall in China and the East Antarctic sea ice of 1 to 3 years before. It is an important basis for further studying the climate change in China.4. There is a very high correlation of the Australia cold high and the East Antarctic sea ice of 2 to 3 months before. The Australia cold high is one of the important indicators for the East Asia monsoon's Yariation, so the East Antarctic sea ice could also be considered as an important indicator for the East Asiamonsson as well as the Australia cold high.