1961—2023年川渝秋季降水气候变化特征分析

Climate Change Characteristics of Autumn Precipitation in Sichuan-Chongqing Region from 1961 to 2023

  • 摘要: 本文利用1961—2023年CN05.1逐日降水格点数据集,通过线性趋势、小波分析和M-K检验等方法,分析了新气候态下川渝秋季降水的时空特征和趋势变化。结果表明:(1)近63 a川渝秋季降水年际变化特征显著,整体呈减少趋势,年际变率为−0.45 mm/a,从20世纪90年代起较常年偏少并持续到21世纪20年代初期,1983年前后发生由多转少的气候突变,突变前后年均减少30.56 mm。(2)秋季总降水量空间分布不均,降水大值中心和年际变率大值中心均分布在四川中南部和川渝东北部,年际变率空间上呈全区一致减少趋势。(3)秋季大雨、暴雨频次减少,暴雨强度增强,大暴雨频次和强度均加强,降水极端性增强;1983年后,秋季中雨、大雨强度在川西地区明显减弱,而大暴雨强度在四川中东部增强。(4)秋季中雨、大雨、暴雨和大暴雨主要分布在四川中南部和川渝东部,对秋季总降水量的最大贡献率分别为44.6%、27.2%、15.9%、4.2%。

     

    Abstract: Based on the CN05.1 gridded daily precipitation dataset from 1961 to 2023, the spatiotemporal characteristics of autumn precipitation in the Sichuan-Chongqing region under the new climate state were analyzed using linear trend analysis, wavelet analysis, and the M-K test.The results show that: (1) Over the past 63 years, the interannual variation of autumn precipitation in the Sichuan-Chongqing region has been remarkable, with an overall decreasing trend at a rate of −0.45 mm/a. Since the 1990s, precipitation has been below the climatological average, persisting into the early 2020s. An abrupt climate change from wet to dry occurred around 1983, with the annual precipitation decreasing by 30.56 mm on average before and after the shift. (2) The spatial distribution of total autumn precipitation is uneven, with precipitation maxima and the centers of high interannual variability both located in central-southern Sichuan and the northeastern part of the Sichuan-Chongqing region. Spatially, the interannual variability shows a consistent decreasing trend across the entire region. (3) The frequency of heavy rain and torrential rain has decreased, while the intensity of torrential rain has increased. The frequency and intensity of extreme torrential rain have both intensified, leading to enhanced precipitation extremity. After 1983, the intensity of moderate and heavy rainfall decreased in western Sichuan, while the intensity of extreme torrential rain increased in central-eastern Sichuan. (4) Modreate rain, heavy rain, torrential rain and extreme torrential rain in autumn are mainly concentrated in central-southern Sichuan and eastern Sichuan-Chongqing region, with their largest contributions to total autumn precipitation being 44.6%, 27.2%, 15.9%, and 4.2%, respectively.

     

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