本文基于1971~2020年共50年夏季四川盆地地区102个站点的逐日降水资料,NCEP/NCAR逐月再分析资料和NOAA逐月海表温度格点资料,基于一元线性回归和合成分析等方法,首先探讨了四川盆地地区连阴雨相关指标的变化特征,其次分析了与四川盆地...本文基于1971~2020年共50年夏季四川盆地地区102个站点的逐日降水资料,NCEP/NCAR逐月再分析资料和NOAA逐月海表温度格点资料,基于一元线性回归和合成分析等方法,首先探讨了四川盆地地区连阴雨相关指标的变化特征,其次分析了与四川盆地地区连阴雨降水量年际变化相联系的异常环流以及海表温度。结果表明:(1) 四川盆地夏季连阴雨降水总量、发生次数及累计天数的空间分布均呈盆地中心少、边缘多的特征,且三者的最大值均在盆地西南边缘。变化趋势上,盆地站点在三个指标上均未体现出一致性的减少,下降趋势都不显著。(2) 四川盆地夏季连阴雨的年际变化与南亚高压和西太副高的位置和强度变化关系密切。对流层中低层西太副高主体位置偏西,中高层南亚高压主体位置东移。在两个高压的相互作用下,盆地区域在对流层低层有垂直上升运动,在对流层高层有强烈辐散运动。(3) 前冬季、春季热带东太平洋海面温度异常偏高,夏季热带中太平洋海面温度异常偏低和热带西太平洋海面温度异常偏高时,引起西太平洋副热带高压异常,有利于西太平洋水汽输送至盆地引起降水异常。另外,在地形作用的影响下,连阴雨降水随着海拔的增加而明显增加。本文的研究结果有利于加深人们对气候变暖背景下四川盆地降水变化特征及其机制的认识。Based on the daily precipitation data of 102 stations in the Sichuan Basin area in summer for 50 years from 1971 to 2020, the monthly reanalysis data of NCEP/NCAR and the monthly sea surface temperature grid data of NOAA, this paper firstly discusses the variation characteristics of the indicators related to consecutive wet day in the Sichuan Basin area based on the methods of univariate linear regression and composite analysis. Then it analyzes the abnormal circulation and sea surface temperature associated with the interannual variation of consecutive wet day precipitation in the Sichuan Basin area. The results show that: (1) The spatial distribution of the total amount of consecutive wet day precipitation, the number of occurrences, and the cumulative number of days in the Sichuan Basin in summer are characterized by less in the center of the basin and more at the edge, and the maximum values of the three are all at the southwest edge of the basin. Regarding the variation trend, the basin stations do not show a consistent decrease in the three indicators, and the downward trend is insignificant. (2) The interannual variation of consecutive wet day in the Sichuan Basin in summer is closely related to the changes in the position and intensity of the South Asian High and the Western Pacific Subtropical High. The main position of the Western Pacific Subtropical High in the middle and lower troposphere is westward, and the main position of the South Asian High in the middle and upper troposphere moves eastward. Under the interaction of the two high pressures, the basin region has vertical upward movement in the lower troposphere and strong divergent movement in the upper troposphere. (3) When the sea surface temperature in the tropical eastern Pacific is abnormally high in the early winter and spring, the sea surface temperature in the tropical central Pacific is abnormally low in the summer and the sea surface temperature in the tropical western Pacific is abnormally high, it causes abnormal subtropical high pressure in the western Pacific, which is conducive to the transport of water vapor from the western Pacific to the basin, causing abnormal precipitation. In addition, under the influence of topography, consecutive wet day precipitation increases significantly with increasing altitude. The research results of this paper are conducive to deepening people’s understanding of the characteristics and mechanisms of precipitation changes in the Sichuan Basin under the background of climate warming.展开更多
文摘本文基于1971~2020年共50年夏季四川盆地地区102个站点的逐日降水资料,NCEP/NCAR逐月再分析资料和NOAA逐月海表温度格点资料,基于一元线性回归和合成分析等方法,首先探讨了四川盆地地区连阴雨相关指标的变化特征,其次分析了与四川盆地地区连阴雨降水量年际变化相联系的异常环流以及海表温度。结果表明:(1) 四川盆地夏季连阴雨降水总量、发生次数及累计天数的空间分布均呈盆地中心少、边缘多的特征,且三者的最大值均在盆地西南边缘。变化趋势上,盆地站点在三个指标上均未体现出一致性的减少,下降趋势都不显著。(2) 四川盆地夏季连阴雨的年际变化与南亚高压和西太副高的位置和强度变化关系密切。对流层中低层西太副高主体位置偏西,中高层南亚高压主体位置东移。在两个高压的相互作用下,盆地区域在对流层低层有垂直上升运动,在对流层高层有强烈辐散运动。(3) 前冬季、春季热带东太平洋海面温度异常偏高,夏季热带中太平洋海面温度异常偏低和热带西太平洋海面温度异常偏高时,引起西太平洋副热带高压异常,有利于西太平洋水汽输送至盆地引起降水异常。另外,在地形作用的影响下,连阴雨降水随着海拔的增加而明显增加。本文的研究结果有利于加深人们对气候变暖背景下四川盆地降水变化特征及其机制的认识。Based on the daily precipitation data of 102 stations in the Sichuan Basin area in summer for 50 years from 1971 to 2020, the monthly reanalysis data of NCEP/NCAR and the monthly sea surface temperature grid data of NOAA, this paper firstly discusses the variation characteristics of the indicators related to consecutive wet day in the Sichuan Basin area based on the methods of univariate linear regression and composite analysis. Then it analyzes the abnormal circulation and sea surface temperature associated with the interannual variation of consecutive wet day precipitation in the Sichuan Basin area. The results show that: (1) The spatial distribution of the total amount of consecutive wet day precipitation, the number of occurrences, and the cumulative number of days in the Sichuan Basin in summer are characterized by less in the center of the basin and more at the edge, and the maximum values of the three are all at the southwest edge of the basin. Regarding the variation trend, the basin stations do not show a consistent decrease in the three indicators, and the downward trend is insignificant. (2) The interannual variation of consecutive wet day in the Sichuan Basin in summer is closely related to the changes in the position and intensity of the South Asian High and the Western Pacific Subtropical High. The main position of the Western Pacific Subtropical High in the middle and lower troposphere is westward, and the main position of the South Asian High in the middle and upper troposphere moves eastward. Under the interaction of the two high pressures, the basin region has vertical upward movement in the lower troposphere and strong divergent movement in the upper troposphere. (3) When the sea surface temperature in the tropical eastern Pacific is abnormally high in the early winter and spring, the sea surface temperature in the tropical central Pacific is abnormally low in the summer and the sea surface temperature in the tropical western Pacific is abnormally high, it causes abnormal subtropical high pressure in the western Pacific, which is conducive to the transport of water vapor from the western Pacific to the basin, causing abnormal precipitation. In addition, under the influence of topography, consecutive wet day precipitation increases significantly with increasing altitude. The research results of this paper are conducive to deepening people’s understanding of the characteristics and mechanisms of precipitation changes in the Sichuan Basin under the background of climate warming.
