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Comparative Analysis of Observation and NWP Data of Downslope Windstorm Cases during 3-Dimensional Meteorological Observation Project in Yeongdong Region of Gangwon province, South Korea in 2020

2020 강원영동 공동 입체기상관측 기간 강풍 사례에 대한 관측자료와 수치모델 비교 분석

  • Kwon, Soon-Beom (Gangwon Regional Office of Meteorology) ;
  • Park, Se-Taek (Gangwon Regional Office of Meteorology)
  • 권순범 (강원지방기상청 예보과) ;
  • 박세택 (강원지방기상청 예보과)
  • Received : 2021.05.20
  • Accepted : 2021.07.26
  • Published : 2021.11.30

Abstract

In order to investigate downslope windstorm by using more detailed observation, we observed 6 cases at 3 sites - Inje, Yongpyeong, and Bukgangneung - during "3-D Meteorological Observation Project in Yeongdong region of Gangwon province, South Korea in 2020." The results from analysis of the project data were as follows. First, AWS data showed that a subsidence inversion layer appeared in 800~700 hPa on the windward side and 900~850 hPa on the leeward side. Second, before strong wind occurred, the inversion layer had descended to about 880~800 hPa. Third, with mountain wave breaking, downslope wind was intensified at the height of 2~3 km above sea level. After the downslope wind began to descend, the subsidence inversion layer developed. When the subsidence inversion layer got close to the ground, wind peak occurred. In general, UM (Unified Model) GDAPS (Global Data Assimilation Prediction System) have had negative bias in wind speed around peak area of Taebaek mountain range, and positive bias in that of East Sea coast area. The stronger wind blew, the larger the gap between observed and predicted wind speed by GDAPS became. GDAPS predicted strong p-velocity at 0600 LST 25 Apr 2020 (4th case) and weak p-velocity at 2100 LST 01 Jun 2020 (6th case) on the lee-side of Taebaek mountain range near Yangyang. As hydraulic jump theory was proved, which is known as a mechanism of downslope windstorm in Yeongdong region, it was confirmed that there is a relationship between p-velocity of lee-side and wind speed of eastern slope of Taebaek mountain range.

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