1966—2018年河西走廊春季寒潮频次及影响因子分析

基于甘肃河西走廊15个国家基准基本站点提供的1966年1月1日~2018年12月31日春季（3~5月）逐日最低气温值数据,利用线性回归分析方法、Spline空间插值法和Mann-Kendall趋势和突变检验法,探讨了河西走廊地区1966—2018年春季（3~5月）寒潮频次变化及其影响因子。研究表明：（1） 1966—2018年河西走廊地区春季（3~5月）单站寒潮频次总体呈现下降趋势〔–0.098次·（10 a）^–1〕,其中1980—2010年寒潮频次呈显著下降趋势,2010年之后下降趋势变缓,未通过显著性检验;区域寒潮53 a来频次总体呈缓慢下降趋势〔–0.015次·（10 a）^–1〕。（2） 近53 a河西走廊地区春季三个月中,单站寒潮总量4月>3月>5月,其中4月、5月寒潮频次下降不明显,3月频次下降显著。（3） 空间上,大致以北大河和黑河干流为界,两河中间区域春季寒潮频次低,而北大河以北和黑河干流以东区域则是寒潮高值区,走廊外围地区寒潮频次较高,且大多呈显著下降趋势,寒潮频次与气温距平存在明显负相关关系,内部地区变化趋势不明显。（4） 河西地区春季寒潮频次受气候变暖、地形和大气环流的影响,寒潮频次变化趋势存在地区差异。研究可提高对甘肃河西走廊寒潮演化过程的认知,为河西走廊气候变化的进一步研究奠定基础。

Frequency and influencing factors of spring cold wave in Hexi Corridor from 1966 to 2018

As an important ecological security zone in western China,Hexi Corridor of Gansu Province is one of the main areas that govern cold waves in China. Our study was based on daily minimum-temperature data from 15 national base stations in the Hexi Corridor for the period 1966–2018. （The data from Wutonggou and Jinta base stations were for 1966–1988 and 1989–2018,respectively;the other 13 stations yielded data for the entire study period.） Using linear regression analysis,spline spatial interpolation,and the Mann-Kendall trend and mutation test to derive frequency-variation characteristics of cold waves and their influencing factors for the Hexi Corridor,we analyzed data for spring （March–May） from the 53 years 1966–2018. The results show the following：（1） The frequency of single-station springtime cold waves in Hexi Corridor during 1966–2018 had a downward trend （-0.098 times per 10 years）;the cold-wave frequency decreased significantly during 1980–2010 and further slowed after 2010,when it failed the significance test. The frequency of regional cold waves showed a slow downward trend during the entire study period （–0.015 times per 10 years） and failed the significance test. （2） In the three springtime months during the study period,the frequency of cold waves for single stations was 0.46 times per year in March,0.59 times per year in April,and 0.38 times per year in May. Thus,the total number of springtime cold waves for single stations was highest in April and lowest in May;the frequency of cold waves in March decreased significantly （while passing the significance test）,whereas the frequencies in April and May did not decrease significantly （failing the significance test）. （3） The frequency of springtime cold waves is relatively low in the middle region,between Beida and Heihe Rivers,whereas north of Beida River and east of Heihe River,the cold-waves frequency data show obvious spatial differences. The frequency was high in the corridor’s peripheral areas,mostly showing a significant downward trend with a roughly semicircular distribution. Despite an obvious negative correlation between the cold-waves frequency and air-temperature anomalies,the trend of change in the interior area is not obvious. （4） With the significant negative correlation between temperature anomalies and decreasing cold-waves frequency and from the analysis of topographic factors,it is apparent that the springtime cold-waves frequency in Hexi Corridor is mainly affected by climate warming,topography,and atmospheric circulation. We found significant regional differences in cold-waves frequency,and further research could improve the recognition of the process of cold-wave evolution in Hexi Corridor of Gansu Province. This could provide guidance for disaster prevention and mitigation in the corridor and also also help predict the trend of future climate change.