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Understanding Relationships Between The 1998 Yangtze River Flood And Northeast Eurasian Blocking, Arthur N. Samel, Xin-Zhong Liang

School of Earth, Environment and Society Faculty Publications

Severe summer monsoon flooding occurred along the Yangtze River Valley (YRV) in 1998. The heaviest precipitation fell during June 8-23 and July 20-29 and coincided with midtropospheric blocking over northeast Eurasia. An index based on the difference between Okhotsk High and west Pacific Low intensity is developed in this study to quantify blocking; analysis shows that blocking and equatorward displacement of the upper-tropospheric east Asian jet preceded (accompanied) the June (July) period. This suggests that heavy rainfall during each interval was caused by different atmospheric processes. An examination of joint variations in the index and YRV precipitation during 1958-1998 revealed …