• Journal of the Korean earth science society
• /
• v.37 no.4
• /
• pp.187-199
• /
• 2016

The purpose of this study is to investigate the formation mechanism of landspout by using the Cloud Resolving Storm Simulator (CReSS). The landspout occurred over Ilsan, Goyang City, the Republic of Korea on June 10, 2014 with the damage of a private property. In synoptic environment, a cold dry air on the upper layers of the atmosphere, and there was an advection with warm and humid air in the lower atmosphere. Temperature differences between upper and lower layers resulted in thermal instability. The storm began to arise at 1920 KST and reached the mature stage in ten minutes. The cloud top height was estimated at 9 km and the hook echo was appeared at the rear of a storm in simulation result. Model results showed that the downburst was generated in the developed storm over the Ilsan area. This downburst caused the horizontal flow when it diverged near the surface. The horizontal flow was switched to updraft at the rear of storm, and the rear-flank downdrafts (RFDs) current occurred from simulation result. The RFDs took down the vertical flow to the surface. After then, the vertical vorticity could be generated on the surface in simulation result. Subsequently, the vertical vorticity was stretched to form a landspout. The cyclonic vorticity of echo hook from simulation was greater than $3{\times}10^{-2}s^{-1}$(height of 360 m) and landspout diameter was estimated at 1 km.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 1988.07a
• /
• pp.52-53
• /
• 1988

• Proceedings of the Korean Society of Crop Science Conference
• /
• 1991.10a
• /
• pp.20-21
• /
• 1991

• Journal of Ocean Engineering and Technology
• /
• v.31 no.5
• /
• pp.325-334
• /
• 2017

This paper reports the conceptual design process for a floating metocean data measurement system (FMDMS) for measuring wind information at sea. The FMDMS consists of three circular pontoons, columns, and a deck, which the LiDAR (lighting detection and ranging) is installed on. The dynamics of the mooring lines and motion responses of the FMDMS were analyzed using commercial codes such as WAMIT and OrcaFlex. One design criterion of the developed FMDMS was to maintain the motion responses as small as possible to enhance the LiDAR's accuracy. Starting with the preliminary design parameters such as the FMDMS's principal dimensions, weight, and important parameters of mooring system, we checked whether the FMDMS met the design requirements at each design stage, and then made modifications as necessary. The developed FMDMS showed a large pitch behavior for a small heave motion.

• Water Engineering Research
• /
• v.5 no.1
• /
• pp.47-54
• /
• 2004

Several computer programs have been developed to make stochastically generated weather data from observed daily data. But they require fully dataset to run WGEN. Mostly, meterological data frequently have sporadic missing data as well as totally missing data. The modified WGEN has data filling algorithm for incomplete meterological datasets. Any other WGEN models have not the function of data filling. Modified WGEN with data filling algorithm is processing from the equation of Matalas for first order autoregressive process on a multi dimensional state with known cross and auto correlations among state variables. The parameters of the equation of Matalas are derived from existing dataset and derived parameters are adopted to fill data. In case of WGEN (Richardson and Wright, 1984), it is one of most widely used weather generators. But it has to be modified and added. It uses an exponential distribution to generate precipitation amounts. An exponential distribution is easier to describe the distribution of precipitation amounts. But precipitation data with using exponential distribution has not been expressed well. In this paper, generated precipitation data from WGEN and Modified WGEN were compared with corresponding measured data as statistic parameters. The modified WGEN adopted a formula of CLIGEN for WEPP (Water Erosion Prediction Project) in USDA in 1985. In this paper, the result of other parameters except precipitation is not introduced. It will be introduced through study of verification and review soon

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• v.10 no.S_1
• /
• pp.23-28
• /
• 2001

A new numerical weather prediction and dispersion model, the Operational Multi-scale Environment model with Grid Adaptivity(OMEGA) including an embedded Atmospheric Dispersion Model(ADM), is introduced as a next generation atmospheric simulation system for real-time hazard predictions, such as severe weather or the transport of hazardous release. OMEGA is based on an unstructured grid that can facilitate a continuously varying horizontal grid resolution ranging from 100 km down to 1 km and a vertical resolution from 20 -30 meters in the boundary layer to 1 km in the free atmosphere. OMEGA is also naturally scale spanning and time. In particular, the unstructured grid cells in the horizontal dimension can increase the local resolution to better capture the topography or important physical features of the atmospheric circulation and cloud dynamics. This means the OMEGA can readily adapt its grid to a stationary surface, terrain features, or dynamic features in an evolving weather pattern. While adaptive numerical techniques have yet to be extensively applied in atmospheric models, the OMEGA model is the first to exploit the adaptive nature of an unstructured gridding technique for atmospheric simulation and real-time hazard prediction. The purpose of this paper is to provide a detailed description of the OMEGA model, the OMEGA system, and a detailed comparison of OMEGA forecast results with observed data.

• Journal of the Korean Solar Energy Society
• /
• v.37 no.6
• /
• pp.79-91
• /
• 2017

The meteorological data of 1 hour interval are required to write a typical weather data for building energy simulation. However, many meterological data are missing and the interpolation method to recover the missing data is required. Especially, lots of meterological data are replicated by linear interpolation method because the changes are not significant. While, the wind velocity fluctuates with the time or locations, so linear interpolation method is not appropriate in interpolation of the wind velocity data. In this study, three interpolation methods, using surrounding wind velocity data, Inverse Distance Weighting (IDW), Revised Inverse Distance Weighting (IDW-r), were analyzed considering the characteristics of wind velocity. The Revised Inverse Distance Weighting method, proposed in this study, showed the highest reliability in restoration of the wind velocity data among the analyzed methods.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 1988.07a
• /
• pp.26-27
• /
• 1988

• Proceedings of the Korean Society for Bio-Environment Control Conference
• /
• 1999.04a
• /
• pp.67-70
• /
• 1999

시설내의 고품질 표고생산을 위하여 동고와 화고의 생육환경을 구명하는 것이 필요하다. 시설재배를 위한 생육환경 구명을 위하여 기상환경을 분석한 결과, 290종균의 발생 범위의 하한치부터 진폭이 시작되어 후기로 갈수록 최고 발생 적온으로 상승하였다. 습도는 화고의 경우, 생육초기는 적정 생육습도가 유효하며, 후기로 갈수록 습도의 일교차가 증가하여 화고의 발생량이 증가하는 것으로 추정된다. 본 연구는 동고 및 화고 발생기간의 기상환경을 분석한 것으로, 추후 시설 내에서의 고품질 표고 생산을 위한 기초 자료로 사용 가능하다.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.1751_1752
• /
• 2009

The accurate measurement of soil resistivity and earthing system resistance is fundamental to electrical safety. However, geological and meterological factors can have a considerable effect on the accuracy of conventional measurements and the validity of the measurement methods. This paper presents optimization method of dc resistivity data acquisition system using ERT.