近60 a新疆塔城地区降水及气象干旱变化特征

Variations of Precipitation and Meteorological Drought in Tacheng Area of Xinjiang in Recent 60 Years

  • 摘要: 利用新疆维吾尔自治区塔城地区9个国家气象观测站1961—2020年逐月降水资料,基于降水量距平百分率(Pa)指数,从干旱发生频率、干旱影响范围和强度等方面,分析塔城地区气象干旱的时空分布特征。结果表明:(1)近60 a塔城地区年平均降水量为211.4 mm,呈现西北部多、中东部少的分布格局。年平均降水量呈显著增多趋势,在1986年发生由少到多的突变。(2)近60 a塔城地区共有14 a发生年尺度干旱,占比为23.33%,其中轻旱9 a,中旱3 a,重旱2 a;季节尺度干旱发生频次以夏季最多,冬季次之,春秋两季相当且最少。(3)近60 a塔城地区年、季尺度干旱站次比呈减小趋势,年、季(除夏季外)干旱强度亦呈减弱趋势,干旱影响范围的缩小和干旱强度的减弱使干旱状况有所缓解。从干旱影响范围来看,局域性干旱和全域性干旱发生频数均较高;从干旱强度来看,以轻度干旱和中度干旱为主。(4)AO、PDO指数的变化及ENSO事件对塔城地区干旱事件的发生具有一定指示意义。

     

    Abstract: Based on the precipitation data of nine national meteorological stations in Tacheng area of Xinjiang from 1961 to 2020, the spatial and temporal distribution characteristics of meteorological drought were analyzed from the aspects of drought frequency, drought impact area and drought intensity by using the percentage anomaly index. The results show that: (1) In recent 60 years, the average annual precipitation was 211.4 mm in Tacheng area, there was more in the northwest of the region and less in the middle and east of the region. The annual precipitation showed a significant increasing trend, and there was a sudden change in 1986 from less to more. (2) The annual frequency of drought in Tacheng area was 23.33%, including 9 times light droughts, 3 times medium droughts and 2 times severe droughts. The highest frequency of seasonal drought was in summer, the secondly in winter, and spring and autumn shared the third place. (3) In recent 60 years, on the annual and seasonal scale, the range of meteorological droughts have reduced. and except in summer, the intensity of meteorological droughts have decreased. The reduction of drought influence range and the weakening of drought intensity alleviated the drought situation. From the perspective of drought impact range, the frequency of local drought and global drought is high. From the perspective of drought intensity, it is mainly mild drought and moderate drought. (4) The change of AO index, PDO index and ENSO events certain affected meteorological drought events in Tacheng area.

     

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