【摘要】 利用NCEP / NCAR数据集中1979～1996年3～7月500 hPa位势高度场资料,经过候平均整理后, 自己定义副高强度、西脊点和脊线,然后对它们进行各种距平处理、小波变换和EOF分析,发现3～7月内副高季节内变化主要表现为三次突变过程,在时间上分别对应着南海季风爆发、江南梅雨发生和梅雨结束,同时,在这段时间内副高活动的年际变化主要有4年左右和8年左右的周期。更多还原

【Abstract】 The 500 hPa geopotential height data used in this paper are from NCEP/NCAR data set for the period from 1979 to 1996(from March to July). Using pentad average, we define the intensity, the west point and mean latitude of the subtropical high ridge. Then the wavelet transform and EOF analysis are performed. It is found that there mainly exist three interseasonal abrupt change processes, and they correspond to the onset time of the South China Sea Summer Monsoon (SCSSM), the beginning and the end of the mei-yu respectively. The interannual variation of the subtropical high in late spring and early summer presents quasi-4-year and 8-year periods.更多还原