20世纪80～90年代我国气候增暖进程的统计事实

CLIMATIC WARMING PROCESS DURING 1980S-1990S IN CHINA

运用统计诊断方法分析了近 5 0年来我国年平均及四季的气温变化特征 ,重点研究了2 0世纪 90年代和 80年代气温变化的主要差异及其增暖进程。结果表明 ,我国年平均气温是呈上升趋势的 ,但 80年代以前年代际变化并不明显 ,升温幅度不大。我国气候增暖始于2 0世纪 80年代后期 ,90年代增暖加速 ,急剧增暖的主要原因是长江流域以南地区经历了由偏冷向偏暖的趋势转变。我国四季气温变化趋势在 80～ 90年代增暖的进程中存在明显差异 :其中冬季增暖开始时间最早、幅度最大、持续时间最长 ;90年代我国气候增暖急剧加速 ,其原因除了冬季气温持续攀升作用外 ,春、夏、秋季气温上升 ,特别是春、夏季增暖幅度的加大、增暖区域的显著扩展也起到很重要的作用。

The changes in annual, winter, spring, summer and autumn air temperatures over China in the last 50 years are analyzed through statistical diagnosis and the focus of the study is put on the difference of change and warming process between 1990s and 1980s. The results show that the annual temperature anomaly has an increasing trend in the last 50 years, but the inter decadal change in annual temperature is not remarkable before 1990. The mean temperature from 1991 to 2000 is much higher than those in the other decades. Their 10 year means are -0.12 °C from 1951 to 1960, -0.10 °C from 1961 to 1970, -0.04 °C from 1971 to 1980, 0.14 °C from 1981 to 1990, 0.57 °C from 1991 to 2000, respectively. The difference between the mean from 1991 to 2000 and the mean from 1981 to 1990 is of statistical significance with a confidence level of α =0.05. The linear trend coefficient of the mean temperature over China is only 0.008 °C per year before 1990, but 0.02 °C per year from 1991 to 2000. The beginning of warming was at the end of the 1980s and the warming speeded up in the 1990s in China, during which period a transition from cold to warm occurred in the south of the Changjiang River Valley. The change trend of temperature and the warming processes in the 1980s and 1990s were very different for four seasons. In winter, the beginning of warming was the earliest with the strongest argument and the longest duration. The main contribution to the steep warming during the 1990s comes from the long lasting higher temperature in winter and the temperature rising in spring, summer, autumn, especially the ever increasing warming argument and the ever expanding warming areas in spring and summer. Only 59% and 31% of stations over China have an increasing trend in spring and summer before 1990, but 83% and 50% from 1991 to 2000.