A Case Study on the Polar Low Developed over the Sea Near Busan on 11~12 February 2011

Abstract

The evolutionary process of the polar low, which caused the heavy snowfall in the East Coast area on 11~12 February 2011, was investigated to describe in detail using synoptic weather charts, satellite imageries, and ERA (European Centre for Medium-Range Weather Forecasts Re-Analysis) -Interim reanalysis data. It was revealed that 1) the polar low was generated over the sea near Busan where a large cyclonic shear in the inverted trough branched from the parent low existed, 2) during the developing and mature stages, there was a convectively unstable region in the lower layer around the polar low and its south side, 3) the polar low was developed in the region where the static stability in the 500~850 hPa layer was the lowest, 4) the result from the budget analysis of the vorticity equation indicated that the increase in the vorticity at the lower atmosphere, where the polar low was located, was dominated mainly by the stretching term, 5) the warm core structure of the polar low was identified in the surface-700 hPa layer during the mature stage, 6) there was a close inverse relationship between a development of the polar low and the height of the dynamic tropopause over the polar low, and 7) for generation and development of the polar low, large-scale circulation systems, such as upper cold low and its combined short wave trough, major low (parent low), and polar air outbreak, should be presented, indicating that the polar low has the nature of the baroclinic disturbance.

WRF Sensitivity Experiments of the Polar Low Development Accompanied by Heavy Snowfall on 11 February 2011 to Orography Specification

“…한편, 하층의 강한 경압 불안정과 상층의 한랭 저기압의 영향으로 해양에서 강하게 발달하는 저기압을 극저기압 (Polar low) 혹은 극 중규모 저기압(Polar mesoscale cyclone)이 라고 하는데, 이러한 중규모 저기압에 의해 대설이 종종 발생 하기도 한다 (Lee et al, 1998;Park and Lee, 2005;Kim et al, 2013;Lee et al, 2016). 특히, 2011년 2월 11~12일에는 동해 남부 해상에서 발달한 극저기압의 직⋅간접적인 영향으 로 영동 지역과 동해안 지역으로 최고 133 cm의 대형 폭설이 내렸고, 이로 인하여 비닐하우스 등 사유시설과 군사시설 등의 공공시설에 피해가 발생하였으며, 총 재산 피해액은 약 350 억 원이었다 (National Emergency Management Agency, 2012).…”