Abstract:

Based on air temperature data in 1955-2014 from 10 meteorological stations in medium section of agro-pastoral ecotone of northern China, Mann-Kendall catastrophe change test and wavelet analysis was used to reveal the variation trend of air temperature, its catastrophe change and the period regulation at different time scales. The results showed that:the annual and seasonal mean air temperature in research region had been rising during these 60 years, and a significantly increasing trend was detected since the 1980s, which arrived at 99% confidence level. The annual mean air temperature increased at a rate of 0.45℃·10a^-1, which was higher than that of the whole nation and the whole world. After 2008, the annual mean air temperature slowly decreased, which was mainly contributed by a higher rate of air temperature decrease in winter. The reason was that the global surface air temperature had stalled; An analysis based on catastrophe change test showed that there was the catastrophe change of annual air temperature in 1986. The catastrophe change time of winter air temperature was the earliest, in 1978, and the catastrophe change of summer air temperature was relatively lagged, in 1991; The period regulation test showed that air temperature in study region had multiple-time scale change features of 5~10 a and 30 a, and the annual and season air temperature gradually has grown slowly and even air temperature has stalled ever since 2008.

Key words: Agro-pastoral ecotone, Temperature time series, Variation trend, Catastrophe change

摘要：

利用1955-2014年中国北方农牧交错带中段10个气象观测站的气温时间序列资料，在分析气温变化结构的基础上运行气候突变检验和小波分析，用以解释气温变化的多时间尺度的复杂结构，分析不同时间尺度下气候气温变化的突变点和周期性变化规律。结果表明：近60 a来研究区内平均气温呈现普遍升高趋势，尤其在20世纪80年代以后升高趋势更加显著，达到99%置信度，升温速率达到0.45℃·10a^-1，高于全国和全球的气温增长率。2008年后区域进入降温过程，冬季降温尤为明显，其原因是全球变化发生停滞；气候突变检验表明区域年平均气温的升温突变发生在1986年，显著升温开始于1991年，冬季升温突变时间最早，发生在1978年，夏季升温突变时间滞后，出现于1991年；周期检验表明区域内气温存在5~10 a和30 a的多重时间尺度结构的变化特征，预计2008年后年平均气温和季节平均气温增加速度将变缓，甚至可能发生变暖停滞。

关键词: 农牧交错带, 气温序列, 变化趋势, 突变