AN ANALYSIS ON GLOBAL CIRCULATION ANOMALIES AND FORMING MECHANISM IN THE PRECEDING MONTH OF PERSISTENT HEAVY RAINFALL EVENTS OVER THE SOUTH OF YANGTZE RIVER VALLEY
ZHAO Lu
TANG Yan-bing
GAO Kun
Abstract：Based on the NCEP/NCAR reanalysis data for 1951-2009,significant global circulation anomalies leading up to persistent heavy rainfall (PHR) events over the South of Yangtze River valley (with 1-month lag) are investigated,and the mechanism that brought about the events are analyzed.The results show that during 3-1 weeks ahead of the PHR events,circulation anomalies are generally located in the Eurasia,the North Pacific Ocean and the South Indian Ocean,and the anomalies in the Eurasia and the South Indian Ocean are two Rossby wave like chains in the subtropical westerlies of the middle and upper troposphere.The dispersion and disappearance of these circulation anomalies made the major circulation of WPSH,the Okhotsk Blocking High and the Meiyu Trough the condition of a phase-lock,therefore causing the formation of circulation characteristics favoring the PHR events.
Keywords：persistent heavy rainfall eventsSouth of the Yangtze River valleycirculation anomalies in the preceding monthmechanism analyses
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：10( 548-557 )