甘肃榆中200年来春季气温的变化

 对祁连山东段余脉半湿润气候区内的树木生长对气候因子的响应关系进行了研究，利用树轮宽度指数分析了200 a来甘肃榆中春季气温的变化特点。响应结果发现年轮宽度指数与春季气温显著相关，达到0.01显著性水平。200 a来春季气温经历4次冷期和3次暖期，以暖期为主，而且冷暖变化具有60 a和15 a周期。另外，冷暖变化趋势与西藏、横断山区的气候变化比较一致。

Change of Spring Temperature in Yuzhong of Gansu Province during Recent 200 Years

Tree-ring increment cores were sampled at Xinglongshan Mountain in Gansu Province.The object of this research is to study the relationship between tree-ring and climate factors,and to analysis the past 200 years climate change.There is positive correlation between tree-ring index and spring temperature.The correlation coefficient is 0.429,which is significant at the 0.01 level.The tree-ring width is limited by spring temperature.According to the tree-ring data,the change of spring temperature for the period A.D.1800 to 1999 shows four cold and three warm periods in the low frequency variations of 11 years moving average since A.D.1800.The result indicated that the Yuzhong area was mainly in a warm state since A.D.1800.After analyzing periodic characteristics,we find that spring temperature since A.D.1800 has 60 years periods and 15 years periods.Seen from the large scale for the last 200 years,there is no obvious warm or cold tendency for spring temperature,but take on an alternative form.Contrasting to the climate change of neighboring area,we find that warm periods correspond well with those of Hengduan Mountains and Xizang.