봄철 강릉지역에서 발생하는 강풍에 대한 연구 (Severe Downslope Windstorms of Gangneung in the Springtime)

서지정보

· 발행기관 : 한국기상학회
· 수록지 정보 : 대기 / 18권 / 3호 / 207 ~ 224페이지
· 저자명 : 장욱, 전혜영

초록

Severe downslope windstorms observed at Gangneung, Korea in the springtime during the last 30 years are studied
to understand their generation mechanisms. 92 severe wind cases are selected for which the maximum instantaneous
wind speeds exceed two standard deviation of total mean plus (18.7 m s-¹). They are categorized into the three mechanisms
(hydraulic jump, partial reflection, and critical-level reflection) proposed in previous studies based on the flow condition,
which is calculated using the wind and temperature profile observed at one upstream rawinsonde station, Osan. Among
the three, partial reflection is found to be the most frequent mechanism for the last 30 years (1976 - 2005). To understand
the role of inversion in generating severe downslope windstorms, horizontal velocity perturbation was calculated analytically
for the atmosphere with an inversion layer. It turned out that the intensity of downslope wind was increased by inversion
layer of specific heights, which are well matched with the observations. For better understanding the generation
mechanisms, two-dimensional numerical simulations are conducted for the 92 severe wind cases using the ARPS model.
In most simulations, surface wind speed exceeds the value of the severe-wind criterion, and each simulated case can be
explained by its own generation mechanism. However, in most simulations, the simulated surface wind speed is larger
than the observed, due to ignoring the flow-splitting effect in the two-dimensional framework.

영어초록

Severe downslope windstorms observed at Gangneung, Korea in the springtime during the last 30 years are studied
to understand their generation mechanisms. 92 severe wind cases are selected for which the maximum instantaneous
wind speeds exceed two standard deviation of total mean plus (18.7 m s-¹). They are categorized into the three mechanisms
(hydraulic jump, partial reflection, and critical-level reflection) proposed in previous studies based on the flow condition,
which is calculated using the wind and temperature profile observed at one upstream rawinsonde station, Osan. Among
the three, partial reflection is found to be the most frequent mechanism for the last 30 years (1976 - 2005). To understand
the role of inversion in generating severe downslope windstorms, horizontal velocity perturbation was calculated analytically
for the atmosphere with an inversion layer. It turned out that the intensity of downslope wind was increased by inversion
layer of specific heights, which are well matched with the observations. For better understanding the generation
mechanisms, two-dimensional numerical simulations are conducted for the 92 severe wind cases using the ARPS model.
In most simulations, surface wind speed exceeds the value of the severe-wind criterion, and each simulated case can be
explained by its own generation mechanism. However, in most simulations, the simulated surface wind speed is larger
than the observed, due to ignoring the flow-splitting effect in the two-dimensional framework.

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