中国南方春季降水的异常研究

A Study of the Climatic Anomaly of the Spring Precipitation in Southern China

摘要: 利用我国南方224个测站，近50 a地面降水资料和NECP资料，采用线性趋势分析、EOF、Mann-Kendall、合成分析等方法，分析了南方春季降水异常变化的规律。结果表明：1) 南方春季降水自西向东递增，高值中心分别在广东和赣闽交界区，而在滇北川南有一干舌区，这个干舌区的存在可能是导致西南地区春季易出现干旱的重要原因之一。近50 a南方春季降水以−2.42 mm/10a的速率不显著减少，其中，3月增多，4月和5月减少，各月的趋势都不显著。春季降水经历了“降–升–降”的波动阶段：1961年~1963年减少，1964年~1975年增多，其后缓慢减少。其中，1960s偏少，1970s~1980s偏多，1990s围绕平均值波动，2000s偏少；春季降水的稳定性，从南北向中部递增，云南–川南变率最大；2) 大多数区域春季降水减少，但滇北–川西南显著增加，黔中–湘中显著减少；3) 春季降水异常主要有3种分布模态：全区一致型、南北差异型和云贵高原型，这种分布与850 hPa风场异常有关联；4) 云南–川南是南方旱涝频率高值中心，另外岭南有次高中心，涝年出现的范围较旱年较为均匀。滇北–川南的干旱主要出现在1960s、1980s后期~1990s后期、2000s末期，洪涝主要出现在1970s~1980s中期、1990s末期~2000s中期。

Abstract: Using the precipitation data of 224 stations in Southern China over the years of 1961-2010 and adopting the methods of linear regression analysis, multinomial fitting, EOF, Mann-Kendall and Glide T-examination etc., we analyzed the spatial anomaly features and time evolution rule of the spring precipitation in Southern China. The results showed that: 1) spring precipitation in Southern China increased from west to east, and the high value of the centers is in eastern Guangdong-border area of Jiangxi and Fujian, while there is a dry tongue area in Northern Yunnan and Southern Sichuan. The presence of this dry tongue area may be an important reason leading to spring drought in southwest region. Spring precipitation was at a rate of 2.32 mm/10awhich did not significantly decrease near 50 a. It increased in March and decreased in December and February; however, the three-month trend was not significant. Spring rainfall experienced a “drop-down-drop” fluctuation stage: it reduced during 1961-1963, increased during 1964-1975, and then decreased slowly. Spring rainfall was less than normal in 1960s, more than normal in 1970s-1980s, around the average in 1990s, and less than normal in 2000s. The stability of spring rainfall increased from north and south to central region. The largest variability of precipitation was in Yunnan-Southern Sichuan. 2) Spring precipitation decreased in most regions, but increased significantly in Northern Yunnan-Southwest Sichuan, and reduced significantly in Guizhou-Hunan. 3) Using the analysis of EOF method, we divide the abnormities of spring precipitation in Southern China into three common distributive modes: unanimous model of all areas, difference model of South-North and model of Yunnan-Guizhou Plateau. This distribution may be related to wind anomaly over 850 hPa. 4) The highest value center of southern flood and drought frequency is in Yunnan-Southern Sichuan, and the second highest center is in south of the Five Ridges. The range of flood years is wider than that of drought years. In Northern Yunnan-Southern Sichuan, drought occurred mainly in 1960s, the late 1980s to the late 1990s, and the late 2000s, and flood occurred mainly in 1970s to 1980s, and the late 1990s to the middle 2000s.