塔里木河流域夏季降水年际和年代变化的环流异常

基于1961-2020年夏季（6-8月）NCAR/NCEP再分析资料和塔里木河流域（简称“塔河”）38个气象站降水资料,使用5年滑动平均分离出塔河夏季降水年代际和年际变化,选出了典型的年际变化的干年和湿年与年代际变化的干期（1963-1986年）和湿期（1989-2018年）,分析了与这两种时间尺度变化相关联的大气环流异常。结果表明,两者的变化不同,影响两者变化的大气环流不同。影响年代际变化的大气环流异常主要表现在欧亚大陆对流层从西北至东南交替出现正负位势高度异常中心,在湿期塔河东部和西部分别出现明显的东风和西南风异常,水汽主要由西北太平洋和印度洋输送至塔河,在干期则与之相反;影响年际变化的大气环流异常主要表现为在塔河东部和西部对流层分别为反气旋异常和气旋异常,在多雨年从南北方向向塔河输送的水汽增多,北风水汽通量异常向流域输送较多,南风水汽通量异常向流域输送较小且主要集中在流域西部,水汽主要由北冰洋洋和印度洋输送至塔河。在干年则与之相反。

The Circulation Anomalies of Interannual and Interdecadal Changes in Summer Precipitation over the Tarim River Basin.

Based on the NCAR/NCEP reanalysis data from summer 1961 to 2020 (June-August) and the precipitation data of 38 meteorological stations in the Tarim River Based on the NCAR/NCEP reanalysis data from summer 1961 to 2020 (June-August) and the precipitation data of 38 meteorological stations in the Tarim River Basin (referred to as "TRB"), the interdecadal and interannual changes of summer precipitation in the TRB were separated by 5-year running average, typical dry and wet years with interannual variations and dry periods (1963-1986) and wet periods (1989-2018) were selected, and the atmospheric circulation anomalies associated with these two time-scale changes were analyzed. The results show that the changes of the two are different, and the atmospheric circulation that affects the changes of the two is different. The atmospheric circulation anomalies affecting the interdecadal variation mainly exhibit the alternation of positive and negative geopotential height anomaly centers in the troposphere of Eurasia from northwest to southeast, in the wet period, obvious easterly and southwesterly wind anomalies in the east and west of the basin, and water vapor is mainly transported from the northwest Pacific Ocean and the Indian Ocean to the TRB, in the dry period, the opposite is true. The atmospheric circulation anomalies affecting the interannual variation are mainly manifested as anticyclone anomalies and cyclonic anomalies in the troposphere in the east and west of the TRB, respectively, in the wet years, the water vapor transported from the north and south to the TRB increases, the north wind water vapor flux anomaly transports more to the basin, the south wind water vapor flux anomaly is small and mainly concentrated in the western part of the basin, and the water vapor is mainly transported from the Arctic Ocean and the Indian Ocean to the TRB, and in the dry year, the opposite is true.