한국농림기상학회지, 제 9권 제2호(2007) (pISSN 1229-5671, eISSN 2288-1859)
Korean Journal of Agricultural and Forest Meteorology, Vol. 9, No. 2, (2007), pp. 100~108
DOI: 10.5532/KJAFM.2007.9.2.100
ⓒ Author(s) 2014. CC Attribution 3.0 License.


경사진 KoFlux 산림유역에서 에디공분산 플럭스 산출에
미치는 좌표회전의 효과

렌민 유안(1), 강민석(1), 박성빈(1), 홍진규(2), 이동호(1), 김 준(1)
(1)연세대학교 대기과학과, (2)조지아 대학교 작물 토양 과학과

(2007년 03월 29일 접수; 2007년 06월 11일 수락)

The Effect of Coordinate Rotation on the Eddy Covariance Flux
Estimation in a Hilly KoFlux Forest Catchment

Renmin Yuan(1), Minseok Kang(1), Sungbin Park(1), Jinkyu Hong(2), Dongho Lee(1), Joon Kim(1)
(1)Dept. of Atmospheric Sciences, Yonsei Univ., Seoul, 120-749, Korea
(2)Lab. for Environmental Physics, Dept. of Crop & Soil Sciences, University of Georgia,
1101 Experiment Street, Griffin, GA 30228, USA

(Received March 29, 2007; Accepted June 11, 2007)

ABSTRACT
The Gwangneung KoFlux supersite, located in a rugged mountain region, is characterized by a low wind speed due to a mountain-valley circulation and rolling terrain. Therefore, it is essential to understand the effect of coordinate rotation on flux measurements by the eddy-covariance method. In this paper, we review the properties of three orthogonal coordinate frames (i.e., double, triple, and planar fit rotations) and apply to flux data observed at the Gwangneung supersite. The mean offset of vertical wind speed of sonic anemometer was inferred from the planar fit (PF) coordinate rotation, yielding the diurnal variation of about ± 0.05 ms-1. Double rotation v = w = 0 produced virtually the same turbulent fluxes of heat, water, and CO2 as those from the PF rotation under windy conditions. The former, however, resulted in large biases under calm conditions. The friction velocity, an important scaling parameter in the atmospheric surface layer, was more sensitive to the choice of coordinate rotation method.

Keyword: KoFlux, Gwangneung supersite, Double rotation, Planar fit, Friction velocity

MAIN

적요

험준한 산지에 위치한 광릉 KoFlux 슈퍼사이트는 기복이 진 지형과 산골 순환으로 인해 풍속이 약한 것이 특징이다. 따라서 에디 공분산 방법을 이용한 플럭스 관측에 좌표회전이 미치는 효과를 이해하는 것이 필수적이다. 본 논문에서는 세 가지의 직교 좌표 체제(이중, 삼중 및 planar fit 회전)의 특징을 살펴 보고, 이들을 광릉 슈퍼사이트에서 관측된 플럭스 자료에 적용하였다. ‘Planar Fit(PF)’ 좌표회전으로부터 유추해 낸 초음파 풍속계의 연직 풍속의 평균 차감은 대략 ±0.05 m s−1이었다. 바람이 부는 경우, 이중 회전(v = w = 0)에서 산출된 열, 수증기 및 CO2의 난류플럭스는 PF 회전에서 나온 결과와 거의 같았다. 그러나 바람이 잔잔한 경우에는 이중 회전이 큰 값의 편의를 나타내었다. 대기 지표층의 중요한 스케일링 모수인 마찰 속도는 좌표 회전 방법의 선택에 따라 더 민감하게 반응하였다.

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