我国南方春季低温冷害气候及其大气环流特征

利用我国南方6省45个站1951－1995年2－4月的月平均气温资料分析该地区春季低温冷害气候特征，发现有7个低温冷害年，1957，1968，1969，1970，1984，1985和1988年，最严重的年份是1968和1988年，严重低温冷害主要发生在3，4月份，严重低温冷害最为频繁的地区是江南南部，南方春季低温冷害年际变化有着明显的阶段性和群发性，80年代我国南方春季低温冷害频繁，50年代次之，60，70年代较少，90年代前期几乎没有，典型的春季低温和高温年份，严洲中高纬度大气环流，西太洋平洋副热带高压以及太平洋热带海洋状况都有显著的差异，特别是，亚洲极涡，纬向环流指数，西太平洋副热带高压比界位置及太平洋暖池的海表面温度等因子均通过了95％（90％）信度水平检验。

CLIMATE OF CHILLING DAMAGE IN SPRING IN SOUTHERN CHINA AND ITS ATMOSPHERIC CIRCULATION FEATURES

By using the monthly averaged temperatures(1951～1995) at observatories in 6 provinces in Southern China, the characteristics of chilling damage in spring in the regions are studied .Seven chilling damage years including 1957, 1968, 1969, 1970, 1984, 1985 and 1988 in spring are recognized and the most serious chilling damage years are 1968 and 1988. The severe chilling damages happen mainly in March or April. And the severe chilling damages appear most frequently in southern part of the south of Yangtze River valley. The inter-annual variation of chilling damage in spring in Southern China is characterized by phase and extensive space synchronization. The southern spring chilling damage occurs most frequently in the 80's, more in the 50's, much less in 60's and 70's, and hardly happen in the earlier 90's. The differences of some physical components including the atmospheric index, anomalous height at 500 hPa geopotential in Northern Hemisphere and anomalous SSTs for Spring(February～April), between typical spring chilling years and typical spring warm years are obvious. Especially, t-test shows that significance of the Asia polar vortex, zonal circulation index, the most northern extension edge of subtropical high of Northern West Pacific and the warm pool of Pacific Ocean, are at 95 %（90 %）.