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投稿时间：2023-10-05 修订日期：2024-08-27
投稿时间：2023-10-05 修订日期：2024-08-27
中文摘要: 基于1981—2020年西藏38个气象站点逐小时降水量资料，采用线性倾向估计、Pearson相关系数、Mann-Kendall突变检验等方法，分析近40年西藏昼夜降水量和夜降水率时空变化特征。结果表明：西藏多年平均的年昼降水量总体上自东向西减少，年夜降水量由东南向西北递减，夜降水量大于昼降水量；雅鲁藏布江中游是西藏夜降水率的中心地带；春季昼夜降水量与海拔高度相关性最显著，夏秋两季和全年的昼夜降水量与经度相关系数最大；夜降水率，在冬季是高纬地区大于低纬地区，而在夏秋两季则是高海拔地区小于低海拔地区。近40年，西藏73.7%的站年昼夜降水量均趋于增加，57.9%的站年夜降水率呈减少趋势，63.2%的站夜降水量变化趋势大于昼降水量；西藏平均年昼夜降水量均呈增加趋势且夜降水量增速大于昼降水量，主要表现在春夏两季；因冬春秋三季夜降水率均减小，导致年夜降水率趋于减小。从年代际变化来看，近40年中，20世纪80年代是年昼夜降水量最少的年代，最大值分别出现在21世纪10年代和20世纪90年代；夜降水率则在20世纪80年代最高、21世纪10年代最低。Mann-Kendall突变检验显示，西藏仅有春季昼夜降水量、冬季夜降水量分别在20世纪90年代末和21世纪初发生了气候突变，前者增多，后者变少；2004年、2011年和2009年分别是冬季、春季和年夜降水率的突变时间。
Abstract:Based on the measured hourly precipitations at 38 meteorological stations in Xizang from 1981 to 2020, the spatio-temporal characteristics of daytime precipitation (Pd) and nighttime precipitation (Pn) and night-precipitation rate (Nr) in recent 40 years are analyzed by the methods of linear trend estimation, Pearson coefficient and Mann-Kendall test. The results show that, in Xizang the multi-year average of annual Pd decreases from east to west, the annual Pn decreases from southeast to northwest, and Pn is larger than Pd. The middle reaches of the Yarlung Zangbo River are the center Nr in Xizang. The correlations between the Pd and Pn and the altitude are most significant in spring, and the correlation coefficients between the Pd and Pn and the longitude are the greatest in summer, autumn and the whole year. In winter, Nr at high latitudes is larger than that at low latitudes. In summer and autumn, Nr at high altitudes is smaller than that at low altitudes. In the past 40 years, the annual Pd and Pn increased at 73.7% of stations in Xizang, while the annual Nr showed a decreasing trend at 57.9% of stations, of which the variation trend of Pn was more obvious than that of Pd at 63.2% of stations. The average annual Pd and Pn increased in Xizang, mainly in spring and summer, and the growth rate of annual Pn was greater than that of Pd. Due to the decreased Nr in winter, spring and autumn, the annual Nr tended to decrease. On the interdecadal scale, the Pd and Pn in the 1980s were the least in Xizang in the past 40 years, with the maxima of annual Pd and Pn appearing in 2010s and in 1990s, respectively. For Nr, the maximum and minimum occurred in the 1980s and in the 2010s, respectively. According to the Mann-Kendall test mutation test, the abrupt changes of climate for the Pd and Pn in spring and Pn in winter occurred in the late 1990s and at the beginning of 21st century, respectively, with the former increasing and the latter decreasing. The years 2004, 2011, and 2009 were the time of mutation for winter, spring, and annual Nr, respectively.
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基金项目:中国气象科学研究院青藏高原与极地气象科学研究所开放课题(ITPP2021K03)、第二次青藏高原综合科学考察研究项目(2019QZKK0106)和西藏科技创新基地自主研究项目(XZ2021JR0001G)共同资助
引用文本：
杜军,黄志诚,程巳阳,德庆卓嘎,王挺,2024.近40年西藏昼夜降水量时空变化特征[J].气象,50(10):1161-1174.
DU Jun,HUANG Zhicheng,CHENG Siyang,DECHEN Dolkar,WANG Ting,2024.Spatio-Temporal Variation Characteristics of Daytime and Nighttime Precipitation in Xizang from 1981 to 2020[J].Meteor Mon,50(10):1161-1174.
杜军,黄志诚,程巳阳,德庆卓嘎,王挺,2024.近40年西藏昼夜降水量时空变化特征[J].气象,50(10):1161-1174.
DU Jun,HUANG Zhicheng,CHENG Siyang,DECHEN Dolkar,WANG Ting,2024.Spatio-Temporal Variation Characteristics of Daytime and Nighttime Precipitation in Xizang from 1981 to 2020[J].Meteor Mon,50(10):1161-1174.
