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Ocean-atmosphere interactions and multi-scale climate variability in a changing climate
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A comparison of two cold events in 2008 and 2018 winter
P-P2-07-S
Mingyue Qin* , Shuanglin Li
Presenter Email: qinmingyue@mail.iap.ac.cn |
| A persistent cold event was identified in East Asia during late January – early February 2018, which exhibits a resemblance to that in the 2007/08 winter. Both events occured in late winter exceeding synoptic time scales, with reductions in sea ice and La Niña phases. A comparative study of the two events was conducted from phenomenon, large-scale circulation conditions and possible reasons. The following conclusions can be drawn. There is a difference in the spatial distribution and duration of the cold SAT anomaly. In the 2007/08 case, cold SAT anomalies occurred in northwestern China, then extended southward along the eastern slope of Tibetan Plateau and reached south China, but with warm SAT anomalies in northeastern China and Tibetan Plateau. In comparison, cold SAT anomalies occurred in most parts of China whereas warm anomalies were found over Tibetan Plateau. Intensified blocking activity and intensified Siberian High are found in both events. In the 2008 events, Rossby wave energy propagates along the subtropical jet, and leads to the formation of southern branch trough in South China and the northward expansion of the western Pacific subtropical high. In the 2018 event, Rossby wave energy originating from Atlantic ocean were splited into two wave trains with one propagating along 50°N and the other along 30°N. They together strengthed the East Asian trough, causing invasion of cold air. |
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