近50年来吉林西部半干旱区气候变化特征

Characteristics of climatic change in semiarid region of western Jilin in recent 50a

根据吉林省西部地区6个具有代表性的气象站1961-2010年间的逐日气温、降水数据,运用趋势分析、小波分析和Mann-Kendall检验等统计方法,对吉林省西部半干旱区气候变化特征进行了分析。研究表明:近50年来,吉林西部半干旱区气温存在明显的增温趋势,以冬季气温升幅最大;降水则呈现减少趋势,夏季表现尤为明显。在不同的时间尺度上,气温、降水的变化趋势存在差异,年平均气温主要有5a左右,12a左右和30a以上的震荡周期,并在1989年发生突变;年平均降水主要有5a左右,30a左右的震荡周期,年际交替频繁。通过分析干燥度指数,吉林西部半干旱区干燥度指数主要存在6a左右、10a左右和35a左右震荡周期,并在1997-2002年之间发生突变,干燥程度总体呈现上升趋势,但上升趋势不明显,上升幅度自西向东逐渐减小。

In recent years,the global warming trend is clear.Semi-arid region of western Jilin locates in the northwest of Jilin province and its fragile ecological environment poses a serious threat to sustainable regional economic growth and agricultural development.In order to provide agricultural production,water use,ecological protection and the policy with theoretical basis,the trend analysis,wavelet analysis,and Mann-Kendall test were used to analyze the characteristics of climate change by using the temperature and precipitation of 6 stations in this region during 1961-2010.The result shows that temperature displayed a ascendant tendency,with the value of 0.37 ℃ /10a.The maximum ascendant tendency was in winter with 0.62 ℃ /10a.The precipitation showed a descendant tendency,which was about 6.75mm /10a,with particularly evident of 13.79 mm /10a in summer.In different time scales,change trends of temperature and precipitation were different.The annual average temperature had about 5a,12a and more than 30a oscillation periods and a mutation in 1989,but the average annual precipitation had about 5a and 30a oscillation periods,with a frequently interannual alternating.On more than 30s time scales,temperature had experienced 3 large time scale changes,whereas precipitation had experienced 4 times.By analyzing the aridity index,it displayed an ascendant tendency generally,but the upward trend is not obvious,and the increase extent decreased gradually from west Baicheng to east Sanchahe.It shows that in recent 50s aridity index changes in semi-arid region of western Jilin fluctuated,which had about 6a,10a and 35a oscillation periods and mutated in 1989-2002.