한국농림기상학회지, 제 15권 제1호(2013) (pISSN 1229-5671, eISSN 2288-1859)
Korean Journal of Agricultural and Forest Meteorology, Vol. 15, No. 1, (2013), pp. 17~125
DOI: 10.5532/KJAFM.2013.15.1.017
ⓒ Author(s) 2014. CC Attribution 3.0 License.


WRF와 ENVI-met 수치 모델을 이용한 산악지형의 바람장 변화 모사

원명수(1), 한선호(2)
(1)국립산림과학원 산림방재연구과, (2)한국기상산업진흥원

(2012년 09월 17일 접수; 2013년 03월 20일 수정; 2013년 03월 21일 수락)

Simulations of Changes in Wind Field Over Mountainous Terrains
Using WRF and ENVI-met Numerical Models

Myoungsoo Won(1), Seonho Han(2)
(1)Division of Forest Disaster Management, Korea Forest Research Institute, 57 hoegi-ro,
Dongdaemun-gu, Seoul, 130-712, Korea
(2)Korea Meteorological Industry Promotion Agency, 52 Songwolgil, Jongno-gu, Seoul, 110-101, Korea

(Received September 17, 2012; Revised March 20, 2013; Accepted March 21, 2013)

ABSTRACT
In this paper we interpreted the changes in wind field over complex mountainous terrains. The results of our study can be applied for predicting the direction of fire spread and for establishing strategies for fire prevention. The study area is bounded by 12×12 km domains of the Samcheok’s long-term ecological research (LTER) site located in the east coast, in which a large-fire had occurred from 7 to 13 April 2000. Because of the area’s complex topography, we compared the result of the Weather Research and Forecasting (WRF) mesoscale model with those observed by four automated weather stations. The WRF simulation overestimated the wind speed by 5 to 8 m/s (~200%) in comparison with those from four automated weather stations. The wind directions observed by the AWSs were from various directions whereas those from WRF model were mostly west wind at all stations. Overall, the simulations by the WRF mesoscale models were not appropriate for the estimation of microscale wind fields over complex mountainous areas. To overcome such inadequacy of reproducing the wind fields, we employed the ENVI-met model over Samcheok’s LTER site. In order to test the model’s sensitivity with the terrain effects, experimental simulations were conducted with various initial conditions. The simulation results of the ENVI-met model showed a reasonable agreement in wind speeds (about 70% accuracy) with those of the four AWSs. Also, that the variations in wind directions agreed reasonably well with changes in terrain effect. We concluded that the ENVI-met model is more appropriate in representing the microscale wind field over complex mountain terrains, which is required to predict fire spread and to establish strategies for forest fire prevention.

Keyword: Forest fire, Mountainous terrain, Microscale wind field, AWS, WRF, ENVI-met

MAIN

적요

본 연구는 복잡한 산악지형에서 바람장 변화를 해석하고, 산불발생시 확산방향을 예측하여 산불방지 전략에 활용하기 위해서 수행되었다. 연구 대상지는 2000년 4월 7일 산불이 발생하여 10일간 진행되었던 삼척지역을 대상으로 하였다. 삼척 산불피해지는 복잡한 산악구조를 가지고 있는데 먼저 중규모 기상 모델인 WRF를 사용하여 대상지에 설치한 AWS(4 지점)의 관측결과와 비교하였다. WRF 모의 결과, 4개 지점의 풍속은 AWS 관측지점의 풍속에 비해 5~8m/s(200% 과대평가) 강하였으며, 관측된 풍향은 지점마다 다양하게 나타난 것에 비해 모의된 풍향은 모든 지점에서 서풍계열로 나타났다. 결과적으로 WRF와 같은 중규모 기상모델은 복잡한 산악지형에서의 바람장 변화를 잘 모의하지 못하였다. 이러한 문제점을 해결하기 위해 미기상 대기유동장 수치모형인 ENVI-met 프로그램을 이용하여 지표면 높이에서 삼척 LTER 지역의 국지규모 바람장을 모의하였다. 지형효과에 의한 모델의 민감도를 위해 다양한 초기 조건(기류, 온·습도, 대기난류, 토양 및 식생 모형)들을 고려하여 분석하였다. ENVI-met 모의결과, 풍속은 실측과 비교할 때 약 70%의 정확도를 보였으며, 풍향은 계곡부와 능선부에서 지형효과로 인한 변화를 잘 반영하였다. 향후 ENVI-met은 산불확산예측 및 산불방지전략 수립을 위해 미기상 대기유동장 수치모형을 이용하여 산악지역의 미기상 해석에 관한 연구가 필요할 것으로 판단된다.

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