1955—2008年渭北旱塬地区气候变化特征

Characteristic of climate change in Weibei dryland from 1955 to 2008

利用渭北旱塬地区5个县(市)1955—2008年的年平均气温、极端高温、极端低温、年总降水、日照时数等实测资料,采用线性分析、趋势线分析5、a滑动平均等方法,对渭北旱塬地区的气候变化特征进行分析.结果表明:(1)近54 a来渭北旱塬地区气温呈现波动上升趋势,以0.25℃/10 a的速度增加,上升趋势较明显,在90年代气温的相对变率最大;(2)降水以6.95 mm/10 a的变化率在减少,共出现6个少雨年份和7个多雨年份;(3)年日照时数以7.02 h/10 a的变化率在减少.由以上分析得出渭北旱塬地区的气候呈现暖干化趋势.

Based on observed data of annual average temperature,extremely high temperature,extremely low temperature and the total precipitation as well as sunshine durations in five counties of Weibei dryland from 1955 to 2008,the characteristics of climate change in Weibei dryland were analyzed by means of linear analysis,trend line analysis and 5-year moving average.Results showed that（1）The temperature in Weibei dryland showed wavelike rises at the average value of 0.25 ℃ per 10 years for recent 54 years,which seem to be the obvious increasing trend.Moreover,the relative variability of temperature is the largest in the 1990s.（2） The rate of the precipitation decreasing is 6.95 mm per 10 years,and in total,there are 6 infrequent rain years and 7 frequent rain years.（3） The rate of the sunshine durations decreasing is 7.02 hours per 10 years.To sum up,the climate in Weibei dryland appeared a warming and drying trend.