摘要
本文根据1871—1986年共116年印度夏季风期（6—9月）雨量与中国华北东部旱涝级别资料研究了两个地区旱涝关系的变化。发现在1921—1950年关系减弱,而1891-1920和1951—1980年关系均较密切。利用相应时期北半球海平面气压图及赤道东太平洋海温资料,讨论了两个地区旱涝关系形成机制和变化原因。
The climates of China and India are under he strong influence of Monsoon, though the geographical circumstance and natural environment differs from each other. Recent studies show close teleconection between the summer rainfall over these two countries. For example, high positive correlation was found between the summer rainfall over India and over China for the period from 1951 to 1980. In present paper, this relationship was reexamined with longer series from 1871 to 1986. The results based on the 116 year data set are as following:
1. Summer floods/droughts in North China correlates closely to the Indian summer (June-September) monsoon rainfall. Correlation coefficient (0.39) between them is significant at 99% of confidence level. But the correlation was unstable. It varys from 0.15 for 1921?950 to 0.58 for 1951-1980.
2. The variations both of floods/droughts over North China and of Indian summer monsoon rainfall closely related to the general atmospheric circulation, especially to the Indian Low and the Western Pacific High. When the north border of the Indian Low moved to the north, the correlation between the floods/droughts over North China and the Indian rainfall become insignificant. At this time, the impact of the Western Pacific High on the floods/droughts in North China was prominent.
3. The relationship between summer floods/droughts in North China and ENSO in the same season and seasons preceded and followed was examined. It was found that the simultaneous correlation for 1-2 season lag of ENSO to the floods/droughts are significant at 95% of confidence level. It infers that when the summer rainfall over North China is less the sea surface temperature in the eastern equatorial Pacific is high in summer, autumn and even in winter. While the ENSO in 1-3 seasons before the summer the correlations are insignificant. However, it may not imply that the droughts in North China are responsible for the formation of ENSO. It is possible that both droughts and ENSO are controlled by a more large scale general atmospheric circulation system.
出处
《地理学报》
EI
CSSCI
CSCD
北大核心
1992年第5期394-402,共9页
Acta Geographica Sinica
基金
国家自然科学基金资助项目。
关键词
旱涝
夏季
季风
降水
遥相关
Floods/droughts in North China
Summer monsoon rainfall
Teleconec-tion
El Nino
