四川地区44年来气候季节划分及变化特征的研究

Seasonal division and change characteristic in Sichuan area during past 44 years

利用四川地区135个台站的逐日温度资料和曾庆存等[1]提出的季节划分方法,讨论了四川各区域的气候季节划分和季节变化,结果表明：（1）1961-2004年期间,四川地区季节的四季分配很不均匀,冬夏季偏长,春秋季偏短;并且四川不同区域间的季节划分差异主要表现在春秋两季的时间长度上。（2）季节划分的年际变化表现为春季西部高原地区有两次时间长度增加和两次减少的变化特征,在两次时间长度增加的过程中出现了一次明显的季节长度突变;高原与盆地过渡区1996年以后春季长度年际差异显著减小,东部盆地地区近年来春季时间长度明显增加。（3）季节强度指数表明,冬季西部高原和中部高原与盆地的过渡地区变暖、夏季在1960-1970年代变冷的趋势;东部盆地冬季在1970年代中后期至1980年代强度变化剧烈、夏季则显示出1982年以前逐渐变冷、以后逐渐变暖的特征。（4）成都城市群表现出春秋过渡季节更加短暂、四季分配更不均匀、气候变化幅度增大的特征。

The ,seasonal division and their change in various Sichuan areas is discussed using the daily mean temperature data of Sichuan 135 stations and the seasonal division method by Zeng Qingcun et al, h is shown that： （ 1 ） Between 1961-2004 each seasonal length is different, summer and winter are longer than spring and autumn, and difference of the seasonal division in different areas is mainly shown by the time scale of spring and autumn. （2） The spring annual variation of the seasonal division is different in western plateau, mid-hills and western basin. In western plateau the spring length increases and decreases twice respectively. The seasonal length changes abruptly during the twice increase. In the mid-hills the annual difference of the spring length reduces obviously since 1996. In eastern basin the spring length obviously increases in recent years. （3） the intensity index of winter and summer shows that western plateau and mid-hills become warmer in winter and colder from 1960 to 1970＇s in summer and in eastern basin the intensity index fiercely changes in winter of 1970- 1980＇ s. It becomes colder gradually before 1982 and warmer gradually after 1982 in summer. （4） In Chengdu areas the transitional seasons are shorter and the ,seasonal length is even more unbalanced and the range of the climatic change increases compared with the whole eastern basin.