基于小波和M-K方法的商丘气温时间序列分析

Time series characters of air temperature based on methods of a wavelet analysis and a Mann-Kendall test in Shangqiu

利用1955—2011年商丘气象站地面逐日气象数据,集成Morlet小波分析法、Mann-Kendall分析法、回归分析法、变异系数等方法,分析近57 a商丘气温序列的年、季周期变化特征、突变特征、变化趋势及年际变率特征。结果表明:根据回归分析、5 a滑动平均分析,商丘年平均气温呈增温趋势,年际变化倾向率为0.17℃/10 a;各季节气温变化趋势差异明显,夏季气温呈下降趋势,年际变化倾向率为-0.08℃/10 a,冬春秋季气温呈增加趋势,冬季增温最显著,冬季气温年际变化倾向率为0.35℃/10 a。根据Mann-Kendall分析,年平均气温突变点为1992年,夏季气温不存在明显突变,冬季气温突变点为1986年。根据小波分析,20世纪50—80年代商丘年平均气温存在准17 a周期信号,之后该周期信号消失,80年代和90年代出现准32 a周期信号,在本研究的整个时间序列上存在准5 a和准2 a周期信号,周期信号显示未来几年可能会出现低温年。商丘年平均气温的年际变异系数为0.04,年际变率较小,年际变化较平稳。商丘作为重要的粮食生产基地,集成多种方法的气温变化特征和趋势预测分析,对该区域的农业种植活动具有重要的指导意义。

Based on the daily air temperature data in Shangqiu weather station from 1955 to 2011 ,the annual,sea- sonal and inter-annual variations of air temperature and their trends, the abrupt changes were analyzed using meth- ods of a Morlet wavelet analysis, a Mann-Kendall analysis, a regression analysis and a variation coefficient. The re- suits indicate that the annual mean air temperature is in an increasing trend by a regression analysis and a 5-year slipping mean analysis, and its rate is 0. 17℃ per decade. The trends of air temperature in four seasons differ sig- nificantly. Air temperature in summer is in a decreasing trend with a rate of - 0. 08 ~C per decade, while that in the other three seasons is in an increasing trend, especially in winter with a rate of 0. 35℃ per decade. An abrupt change of mean annual air temperature appears in 1992 according to the Mann-Kendall analysis, while that for winter is in 1986. There is not the abrupt change for summer air temperature. According to the Morlet wavelet analysis,there is a 17-year cycle for the annual mean air temperature from 1950s to 1980s and then it disappears after- wards,while there is a 32-year cycle from 1980s to 1990s. There are a 5-year cycle and a 2-year cycle from 1955 to 2011 in the study area. It suggests that low temperature could appear in the future according to the cycle signals. The inter-annual variation coefficient of the mean air temperature is 0. 04 and it is stable, and its variation rate is weak. The analysis of temperature variation characteristic and trend prediction has an important guiding signifi- cance for agricultural planting activities of Shangqiu.