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Analysis of the Snow Storms Affecting China in January 2008. Prepared by Min Wen, Song Yang, Arun Kumar, and Peiqun Zhang. Factors to Attribute External La Ni na Subtropical northwestern Pacific SST Internal Middle East jet stream AO/NAO Subtropical northwestern Pacific high.
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Analysis of the Snow Storms Affecting China in January 2008 Prepared by Min Wen, Song Yang, Arun Kumar, and Peiqun Zhang Factors to Attribute External La Nina Subtropical northwestern Pacific SST Internal Middle East jet stream AO/NAO Subtropical northwestern Pacific high
What Happened? Patterns of Jan08 T and P Anomalies
What Happened? Jan 08 U200, H500 and Their Anomalies
Role of the Middle East Jet Stream Patterns associated with MEJS (Yang et al. 2004, JCLI)
Conclusions • The positive AO and strong Middle East jet stream in January 2008 played an important role in the snow storms. • The importance of AO and the jet stream has been also demonstrated by the linear correlations for 1979-2008 and by historical events. • Extremely strong La Nina and farther north ridgeline of the subtropical northwestern Pacific high in January 2008 were also important, as shown in historical events. • However, the general correlations of southern China temperature and precipitation with Nino3.4 SST and the subtropical high are opposite with the signs of Jan08 temperature and precipitation anomalies. • The Middle East jet stream and AO contributed both cold and wet conditions to central-southern China and were more important than the subtropical western Pacific high and La Nina, which enhanced water vapor supply to the region.