关键词: 夏季高温, 经验正交函数分析, 大气环流, 海温

Abstract:

Based on the data for 193 meteorological observation stations in eastern China from 1955 to 2005, the authors analyzed the spatial and temporal characteristics of summer high-temperature events (daily maximum temperature above 35℃). Empirical orthogonal function (EOF) analysis reveals that there are three main patterns for the high-temperature events. The first EOF pattern is Characterized by a uniform anomaly over the whole east China with a center along the Yangtze River valley.The second is a dipole pattern with two centers in southernmost China and the areas to north, and the third mode shows an out of phase pattern between east and west parts of the area. These patterns are tightly related to the atmospheric circulation. The results show that ENSO, Equatorial Indian Ocean and Western Pacific Warm Pool SST could affect the frequency of summer high temperature by influencing the Western Pacific and East Asia atmospheric circulation. ENSO and Western Pacific Warm Pool have a great impact on the first EOF. And the relationship between the second EOF and Equatorial Indian Ocean SST is a significantly negative correlation. The relations between high temperature and the preceding SST of "key regions" are studied; there are evident positive correlations between the preceding summer SST of Western Pacific Warm Pool and the first EOF, which is negatively correlated with the preceding winter SST of Equatorial East Pacific. And the second EOF is most impacted by the preceding winter SST of Equatorial Indian Ocean.

Key words: summer high temperature, EOF analysis method, atmospheric circulation, SST