Temperature Variation over East Asia during the Lifecycle of Weak Stratospheric Polar Vortex

• Published in: Journal of Climate
• Main Authors: Woo, SH, Kim, BM, Kug, JS
• Format: Article in Journal/Newspaper
• Language: English
• Published: AMER METEOROLOGICAL SOC 2015
• Subjects: SURFACE AIR-TEMPERATURE; NORTHERN ANNULAR MODE; WINTER MONSOON; ARCTIC OSCILLATION; SUDDEN WARMINGS; WEATHER REGIMES; CLIMATE-CHANGE; COLD SURGES; PART I; HEMISPHERE; Arctic; Pacific; Climate change; North Atlantic; North Atlantic oscillation
• Online Access: https://oasis.postech.ac.kr/handle/2014.oak/35278; https://doi.org/10.1175/JCLI-D-14-00790.1

The authors investigate the circulation change during the life cycle of a weak stratospheric polar vortex (WSV) event and its impact on temperature variation over East Asia. The lower-tropospheric temperature over East Asia strongly fluctuates despite the slow decay of stratospheric circulation and the continuously negative Arctic Oscillation (AO) pattern during the WSV event. The temperature fluctuation is critically influenced by the variation of the East Asian upper-level coastal trough (EAT), which may be coupled to the stratospheric circulation during the WSV events. The EAT is deepened anomalously during the Peak phase (from lag -5 to lag 5 day) of the WSV, and East Asian temperature is lowest during this phase. During the next period (Decay-1 phase: from lag 6 to lag 16 day), in spite of the slowly decaying WSV condition, the cold temperature anomaly over East Asia is suddenly weakened; this change is caused by a westward-propagating signal of an anticyclonic anomaly from the North Pacific to East Asia. After about two weeks (Decay-2 phase: from lag 17 to lag 27 day), the cold conditions over East Asia are restrengthened by an intensification of EAT, which is related to the eastward propagation of a large-scale wave packet originating from a negative North Atlantic Oscillation (NAO)-type structure in the Decay-1 phase and its delayed influence on the East Asia region. 1 1 9 2 scie scopus