南极气候和海冰的时空变化特征及其与太平洋海温场的关系

应用1973～1999年南极气温和海冰资料,分别对它们进行了统计分析,结果表明,南极的最低温度中心位于东南极大陆(东方站),这种分布特征是与南极地形相对应的.南极东方站的年平均地面气温是-55.3℃;地面最高气温出现在12月至翌1月,其温度为-32.1℃;地面最低气温出现在8月,其温度为-68.2℃.南极各地区的地面气温具有不同的变化特征.根据温度的变化特征,将南极的气候分为4种类型:南极大陆型、南极半岛型、东南极沿岸型和海湾型.近年来南极半岛的气温有明显升高的趋势,而东南极沿岸的气温有明显下降的趋势,它们的变化呈明显的反位相.南极海冰与南极气温变化有较好的对应关系,气温升高的南极半岛的海冰有减少的趋势,而气温下降的东南极的海冰有增加的趋势.这种结果很难用温室效应来解释南极与全球气候变化的差异.东南极海冰变化与南太平洋的海温场存在密切关系,其影响过程是通过南极海冰范围的异常增加或减少,直接影响南极绕极流的冷暖结构及其异常冷暖水的经向输送,从而导致热带和副热带太平洋上层海温场的异常变化.

Spatio-temporal characteristics of antarctic temperature and sea ice and their relationship

Spatio-temporal characteristics of antarctic temperature and sea ice from 1973 to 2000 have been statistically analyzed.Result shows that: the lowest temperature center in Antarctica lies in Southeast Antarctic Mainland, and the distribution characteristic corresponds with the antarctic topography; the annual temperature of Vostok station is -55.3.The highest temperature is -32.1℃ between December and January next year, and the lowest is - 68.2 in August.The surface temperature of different sectors in Antarctica shows different characteristics.According to their variable characteristics, the climate of Antarctica can be divided into four types: Antarctic Continent type, Antarctic Peninsula type, southeast pole coast type and gulf type.In recent years, there is an obvious warming trend in the Antarctic Peninsula, however an obvious colding trend in the southeast pole coast, and their variation shows obvious anti-phase.There is a close response relationship between the sea ice and the temperature in Antarctica, the sea ice becomes least where it becomes warmer in the Antarctic Peninsula, however the sea ice becomes more where it becomes colder in southeast pole.It is difficult to explain such result by the effect of green-house.The anomalous variation of the antarctic sea ice extent has an influence on the warmer and cooler structure of the Antarctic Circumpolar Current and on the long itudinal transportation of ano malous warmer and cooler water, and then leads to the anomalous variation of upper ocean in the tropical and subtropical Pacific.