近60 a哈密市极端气温时空变化特征

Spatial and temporal variation characteristics of extreme temperatures in Hami City in the past 60 years

选取哈密国家气象基准站1961—2019年日最高与最低气温气象资料,采取一元线性回归法、10 a滑动平均、Mann-Kendall法、滑动t检验和主成分分析法等方法对哈密市极端气温时空变化特征进行分析,为预测未来气温变化趋势,增强对极端气温事件的应对能力,减轻气象灾害对哈密市农业生产造成的危害提供一定依据。结果表明:(1)哈密市极端气温指数变化具有不对称性,冷暖指数变化相反,夜指数变暖幅度大于昼指数。季节上看,大部分极端气温指数在夏季、秋季变化幅度更大。(2)近60 a来哈密市极端低温事件频率显著降低,其中霜冻日数下降最为显著,下降幅度为-4.59 d·(10a)-1;极端高温事件频率增加、强度显著增强;生长季度长与热持续指数变化幅度趋于一致,冷持续指数变化相反。(3)极端气温冷指数对气候变化更为敏感,突变发生在20世纪80年代中和90年代末,暖指数和持续指数突变时间为20世纪90年代末。(4)2个主成分累计方差贡献率为76.453%,极端气温事件变化与气温变暖相关性较高,冷暖指数呈负相关,冷夜日数、冷昼日数、霜冻日数、暖夜日数、暖昼日数是哈密市气温升高的主要因素。

The meteorological data of the daily maximum and minimum temperatures of Hami City National Me-teorological Reference Station,Xinjiang,China from 1961 to 2019 were selected to predict future temperature changes in the city.The spatiotemporal variation characteristics of extreme temperature in Hami City were ana-lyzed using the univariate linear regression method,10 a moving average,Mann-Kendall method,moving t test,and principal component analysis method,which provided a certain basis for determining the future temperature trend,enhancing the city’s ability to respond to extreme temperature events,and reducing the harm caused by me-teorological disasters to agricultural production in Hami City.The results showed the following:(1)The change in the extreme temperature index in Hami City is asymmetric,the change in cold and warm indexes is opposite,and the warming amplitude of the night index is greater than that of the day index.Seasonally,most extreme tem-perature indices vary more widely in summer and autumn.(2)In the past 60 years,the frequency of extreme low-temperature events in Hami City decreased significantly,among which frost days decreased most significantly,with a decrease of-4.59 d·(10a)-1.The frequency and intensity of extreme heat events have increased significant-ly.The growth season length tends to be consistent with the change of the thermal persistence index,while the change of the cold persistence index is the opposite.(3)The extreme temperature and cold indices are more sensi-tive to climate change.The abrupt changes occurred in the mid-1980s and the late 1990s,and the abrupt changes in the warm and persistent indices occurred in the late 1990s.(4)The cumulative variance contribution rate of the two principal components was 76.453%,the correlation between extreme temperature events and temperature warming was high,and the cold and warm index was negatively correlated.Cold nights,cold days,frost days,warm nights,and warm days were the main factors for the temperature increase in Hami City.