The Relationship between the Variation of Zephyr Index in the Southern Hemisphere and the Rain Patterns in China during Summer

Based on the monthly mean reanalysis data of geopotential height at 500 hPa from the NCEP/NCAR during 1950-2007, the characteristics of the anomaly height fields at 500 hPa from December to February and from June to August in the Southern Hemisphere corresponding to the three rain patterns in China during summer were discussed. The multivariate analysis of variance was used to find the key area A of zephyr index corresponding to the rain patterns, and the relationship between zephyr index in key area A and the precipitation during summer in China had been investigated. It was also analyzed to find an affiliation which the abnormal zephyr in the Southern Hemisphere from December to February would affect the zephyr in the Northern Hemisphere in summer, thereby impacted the distribution of rain patterns in China. According to the study, the anomaly height fields corresponding to the rain patterns exhibited different distributions, and the significant discrepancy area was in (35°N-50°N, 35°E80°E). The key area A from December to February located in 22.5°W-2.5°W, and from June to August was in 10°E-55°E. The precipitation in China in summer was linked to the fluctuation of zephyr index in the key area A. The abnormality of zephyr in the Southern Hemisphere in winter could forecast the variation of zephyr in the key area in the Northern Hemisphere in summer. The significant anticorrelation area of zephyr index in the Southern Hemisphere from December to February and the height field in the Northern Hemisphere in summer distributed in Lake Baikal. The latitudinal transmit of atmospheric circulation between the Southern and the Northern Hemispheres was one of the trace of the interaction between zephyr in the Southern Hemisphere and that in the Northern Hemisphere possibly. The abnormal zephyr in the Southern Hemisphere in winter would affect the intensity of trough in Lake Baikal, with which the zephyr in the key area was abnormal in the Northern Hemisphere, thereby affecting the distribution of rain pattern in China over summer.