https://repository.kopri.re.kr/handle/201206/5209 2026-04-07T05:39:55Z https://repository.kopri.re.kr/handle/201206/6078 Title: Temperature Variation over East Asia during the Lifecycle of Weak Stratospheric Polar Vortex Authors: Woo, Sung-Ho; Kug, Jong-Seong; Kim, Baek-Min Abstract: 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. 2015-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/6447 Title: Seasonal Dependence of the Effect of Arctic Greening on Tropical Precipitation Authors: Kang, Sarah M.; Kim, Baek-Min; Frierson, Dargan M. W.; Jeong, Su-Jong; Seo, Jeongbin; Chae, Yoojeong Abstract: mospheric energy transport across the equator by an anomalous Hadley circulation, resulting in a northward shift of the tropical precipitation. In contrast, in boreal fall, the slight increase in insolation over the Arctic is more than offset by increased outgoing longwave radiation and reduced surface turbulent fluxes in midlatitudes, from the warmer atmosphere. As a result, the Northern Hemisphere atmosphere loses energy, which is compensated by a northward cross-equatorial atmospheric energy transport, leading to a southward shift of the tropical precipitation in boreal fall. Thus, although Arctic vegetation is changed throughout the year, its effect on tropical precipitation exhibits substantial seasonal variations. 2015-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/6094 Title: A physical mechanism of the precipitation dipole in the western United States based on PDO-storm track relationship Authors: Sung, Mi-Kyung; Woo, Sung-Ho; An, Soon-Il; Kim, Baek-Min Abstract: It is known that the western United States (US) precipitation displays a north-south contrast, i.e., the so-called "precipitation dipole," during El Nin？o and La Nin？a winters. Furthermore, the Pacific Decadal Oscillation (PDO) has been known to modulate this precipitation dipole. However, the underlying physical mechanism regulating this modulation is not well understood. This study revisits previous studies and suggests a physical mechanism of precipitation dipole modulation based on the PDO-storm track relationship. 2014-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/6041 Title: Intensified Arctic warming under greenhouse warming by vegetation-atmosphere-sea ice interaction Authors: Jeong, Jee-Hoon; Jun, Sang-Yoon; Kim, Baek-Min; Deliang Chen; Hans Linderholm; Kug, Jong-Seong Abstract: Observations and modeling studies indicate that enhanced vegetation activities over high latitudes under an elevated CO2 concentration accelerate surface warming by reducing the surface albedo. In this study, we suggest that vegetation-atmosphere-sea ice interactions over high latitudes can induce an additional amplification of Arctic warming. Our hypothesis is tested by a series of coupled vegetation-climate model simulations under 2xCO2 environments. The increased vegetation activities over high latitudes under a 2xCO2 condition induce additional surface warming and turbulent heat fluxes to the atmosphere, which are transported to the Arctic through the atmosphere. This causes additional sea-ice melting and upper-ocean warming during the warm season. As a consequence, the Arctic and high-latitude warming is greatly amplified in the following winter and spring, which further promotes vegetation activities the following year. We conclude that the vegetation-atmosphere-sea ice interaction gives rise to additional positive feedback of the Arctic amplification. 2014-01-01T00:00:00Z