• 한국대기환경학회지
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• 제14권5호
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• pp.465-478
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• 1998

In this study, seasonal variations of the dry deposition velocity and deposition flux for the sulfur dioxide were analysed. The field observation was performed during one year (from November 1, 1995 to October 31, 1996) in Chunchon basin. The turbulence data were measured by 3-dimensional sonic anemometer/thermometer, and were estimated by mean meteorological data obtained at two heights (2.5 m and 10 m) of meteorological tower. Also, the estimation methods were evaluated by comparing the turbulence data. The results showed that the estimated dry deposition velocity and turbulence parameter such as uc and sensible heat flux using mean meteorological data were relatively similar to the sonic measurements, but all showed somewhat large differences. The dry deposition velocity was large in summer and small in winter mainly due to canopy resistance (rc). The major factor which affects diurnal variation of the velocity was aerodynamic resistance (rw). The SO2 dry deposition flux was large in winter and small in summer in Chunchon.

• 한국환경과학회지
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• 제9권2호
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• pp.109-114
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• 2000

The purpose of the present study is to develope the estimation scheme for sensible heat flux by semi-empirical approach using routine meteorological data such as solar radiation and air temperature. To compare observed sensible heat flux with estimated sensible heat flux, the sensible heat fluxes were measured by three dimensional sonic anemometer-thermometer. The field observation was performed during 1 year from December 1, 1995 to November 30, 1996 on a rice paddy field in Chunchon basin. The heat fluxes were measured at a heights of 5m and mean meteorological variables were obtained at two levels, 2.5m(or 1.5m) and 10m. Since condition of rice paddy field such as, wetness of the field, roughness length, vary widely, we devided annual data to 5 periods. Comparing with two sensible heat fluxes, the results showed that the correlation coefficients were more than 0.86. Thus, we can conclude that the estimation method of sensible heat fluxes using routine meteorological data is practical and reliable enough.

• 한국항행학회논문지
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• 제15권1호
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• pp.25-31
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• 2011

최근에는 NMEA 2000 프로토콜이 SOLAS 선박의 실시간 네트워크 장비의 표준으로 인증 된다. 본 논문에서는 항해 필수 장비인 초음파 센서를 이용한 NMEA 2000이 탑재된 2차원 풍향 풍속계를 개발하였다. 개발된 시스템은 NMEA 2000 장비와의 연결을 테스트하기 위해 수심, 속도, GPS 장비로 구성된 NMEA 2000 네트워크에 연결하였으며, 기존에 제작된 타사 풍향 풍속계와 비교하기 위해 기능시험을 수행하였다.

• Wind and Structures
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• 제24권6호
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• pp.613-635
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• 2017

Strong downslope windstorms often occur in the Liguria Region. This part of North-Western Italy is characterised by an almost continuous mountain range along its West-East axis consisting of Maritime Alps and Apennines, which separate the Padan Plain to the North from the Mediterranean Sea to the South. Along this mountain range many valleys occur, frequently perpendicular to the mountain range axis, where strong gap flows sometimes develop from the top of the mountains ridge to the sea. In the framework of the European projects "Wind and Ports" and "Wind, Ports, and Sea", an anemometric monitoring network made up of 15 (ultra)sonic anemometric stations and 2 LiDARs has been realised in the three main commercial ports of Liguria. Thanks to this network two investigations are herein carried out. First, the wind climatology and the main statistical parameters of one Liguria valley have been studied through the analysis of the measurements taken along a period of 4 years by the anemometer placed at its southern exit. Then, the main characteristics of two strong gap flows that occurred in two distinct valley of Liguria are examined. Both these studies focus, on the one hand, on the climatological and meteorological characterisation of the downslope wind events and, on the other hand, on their most relevant quantities that can affect wind engineering problems.

• Wind and Structures
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• 제17권1호
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• pp.21-41
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• 2013

Wind-induced vibrations of mast arms of cantilever traffic signal structures can lead to fatigue failure. Two such structures were instrumented each with a sonic anemometer and a camera that records the motions of the tip of the arm. It was observed throughout this experiment that large amplitude vertical vibrations of mast arms with signals with backplates occur for the most part at low wind speed ranges, between 2 to 7 m/s, and as the wind speed increases the amplitude of the vertical vibrations decreases. The results of these experiments contradict the generally accepted belief that vortex shedding does not cause significant vibrations of mast arms that could lead to fatigue failure, which have been attributed to galloping in the past. Two damping devices were tested with mixed results.

• 한국전자통신학회논문지
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• 제16권1호
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• pp.157-164
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• 2021

순천만 갯벌에서 3차원 초음파풍속계로 바람과 기온을 측정하고, 적외선 센서를 이용하여 이산화탄소 농도를 측정하였다. 일반적으로 기온이 증가하면 대기 중의 이산화탄소 농도가 증가하고, 기온이 감소하면 이산화탄소도 감소한다. 그러나 일몰 직후에는 광합성이 줄어들기 때문에, 기온이 감소함에도 이산화탄소 농도는 증가하였다. 또한 갯벌이 해수로 덮이게 되는 고조기에는 기온 증가에도 불구하고 대기 난류가 강하게 나타나 이산화탄소 농도가 감소하였다. 이산화탄소의 농도 변화에 미치는 갯벌 생태계의 광합성과 호흡 그리고 대기 난류의 영향에 대한 정량적 평가가 필요하다.

• 대기
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• 제26권3호
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• pp.401-412
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• 2016

A 3D sonic anemometer has been installed at Yongpyong alpine slope since Oct. 23th 2014 to observe the slope winds and to analyze turbulent characteristics with the change in surface cover (grass and snow) and the synoptic wind strength. Eddy covariance method has been applied to calculate the turbulent quantity after coordinate transformation of a planar-fit rotation. We have carefully selected 3 good episodes in the winter season (23 October 2014 to 28 February 2015) for each category (9 days in total), such as grass and snow covers in case of weak synoptic wind condition, and grass cover of strong synoptic wind. The diurnal variations of the slope winds were well developed like the upslope wind in the daytime and downslope wind in the nighttime for both surface covers (grass and snow) in the weak synoptic forcing, when accordingly both heat and momentum fluxes significantly increased in the daytime and decreased in the nighttime. Meanwhile, diurnal variation of heat flux was not present on the snow cover probably in associated with significant fraction of sunlight reflection due to high albedo especially during the daytime in comparison to those on the grass cover. In the strong synoptic regime, the most dominant feature at Yongpyong, only the southeasterly downslope winds were steadily generated irrespective of day and night with significant increases in momentum flux and turbulent kinetic energy as well, which could suggest that local circulations are suppressed by the synoptic scale forcing. In spite of only one season analysis applied to the limited domain, this kind of an observation-based study will provide the basis for understanding of the local wind circulation in the complex mountain domain such as Gangwon in Korea.

• 대기
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• 제24권2호
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• pp.197-206
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• 2014

The effects of different averaging operators and atmospheric stability on the turbulent fluxes are investigated using the vertical velocity, air temperature, carbon dioxide concentration, and absolute humidity data measured at 10 Hz by a 3-dimensional sonic anemometer and an open-path $CO_2/H_2O$ infrared gas analyzer installed at a height of 18.5 m on the rooftop of the Jungnang KT building located at a typical residential area in Seoul, Korea. For this purpose, 7 different averaging operators including block average, linear regression, and moving averages during 100 s, 300 s, 600 s, 900 s, and 1800 s are considered and the data quality control procedure such as physical limit check and spike removal is also applied. It is found that as the averaging interval becomes shorter, turbulent fluxes computed by the moving average become smaller and the ratios of turbulent fluxes computed by the 100 s moving average to the fluxes by the 1800 s moving average under unstable stability are smaller than those under neutral stability. The turbulent fluxes computed by the linear regression are 85~92% of those computed by the 1800 s moving average and nearly the same as those computed by 900 s moving average, implying that the adequate selection of an averaging operator and its interval will be very important to estimate more accurate turbulent fluxes at urban area.

• 한국농림기상학회지
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• 제9권2호
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• pp.100-108
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• 2007

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 $\pm0.05ms^{-1}$이었다. 바람이 부는 경우, 이중 회전 $(\bar{v}=\bar{w}=0)$에서 산출된 열, 수증기 및 $CO_2$의 난류 플럭스는 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.