近45年宁夏极端气温与太平洋海温的遥相关  

Extreme Temperature Change in Ningxia and Its Teleconnection with Pacific SST and Atmospheric Circulation at 500 hPa in Recent 45 Years

作　　者：陈豫英[1] 陈楠[1] 王式功[2] 郑广芬[1] 陈晓娟[1] 穆建华[1] 纳丽[1] 邵建[1] 

机构地区：[1]宁夏气象防灾减灾重点实验室,宁夏银川750002 [2]兰州大学大气科学学院,甘肃兰州730000

出　　处：《干旱区研究》2008年第2期273-281,共9页Arid Zone Research

基　　金：国家科技部社会公益研究专项(2004DIB3J121);中英气候变化双边合作研究项目(2001-BA611B-04-06-01);国家气象局气候变化专项(CCSF2006-16,CCSF2007-27)资助

摘　　要：利用1961—2005年标准化宁夏极端气温、SST和北半球500hPa环流特征量资料，采用REOF、小波分析、最大熵谱、Mann—Kendall检验等方法，分析了极端气温的时空变化特征及其与SST和同期北半球500hPa环流特征量的遥相关。结果表明：宁夏极端气温的年代际气候特征表现为一致的上升趋势，异常敏感区在宁夏北部和六盘山区；极端最低气温在1984年前后发生突变，突变后气温转暖，中部半干旱带增温最明显，有显著的2．32年和4．40年周期；极端最高气温的增暖过程经历了2个阶段，其中1976年的增暖趋势最显著，突变后宁夏中北部增温最明显，有显著的3．14年周期；虽然突变后高温日数明显增加，但仍有异常的低温事件发生；当前一年1～6月加利福尼亚西岸海区温度偏高、同期冬季西太平洋副高西升北抬、面积增大、强度增强、亚洲区极涡面积收缩、青藏高原500hPa位势高度增高时，极端最低气温偏高；当前一年冬季赤道东太平洋海区呈La Nina型分布、同期夏季北半球极涡减弱时，副高加强北抬，极端最高气温偏高。Based on the data of standardized extreme temperature in Ningxia, SST and the characteristic values of 500-hPa circulation over Northern Hemisphere during the period of 1961 -2005, in this paper the spatiotemporal change of extreme temperature and its teleconnection with SST and the values of 500-hPa circulation over Northern Hemisphere are analyzed using the means of REOF, wavelet analysis, maximum entropy spectrum, Mann-Kendall test, etc. The results show that the extreme temperature in Ningxia is in an increase trend, and the most sensitive ar- eas are located in north Ningxia and the Liupan Mountain ; an abrupt change of the extreme minimum temperature occurred around 1984, and then the temperature begins to increase, especially in central Ningxia, and there are the significant temperature increase periods of 2.32 and 4.40 years. The increase of extreme maximum temperature has ex- perienced 2 phases, the warming trend was the most significant in 1976, the temperature increase is the most significant in the central and northern parts of Ningxia, and there is a significant temperature increase period of 3.14 years. Although the high-temperature days increase significantly after such change, the abnormal low-temperature events occur sometimes. The extreme minimum temperature is increased when the SST in the west coastal area of California is high during the period from January to June in the previous year, the subtropical ridge over the west Pacific Ocean moves westward and northward, its area and intensity are increased, the area of polar vortex over Asia is reduced, and the 500-hPa geopotential height over the Qinghai-Tibetan Plateau is increased. The extreme maximum temperature is increased when a La Nina event occurs over the sea area of equator east Pacific Ocean in previous winter, the polar vortex of the Northern Hemisphere is reduced in summer, and the subtropical ridge is strengthened to move northward.

关 键 词：极端气温 时空变化 太平洋海温 环流特征 遥相关 宁夏 

分 类 号：P467[天文地球—大气科学及气象学] P731.11