• 대기
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• 제18권3호
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• pp.237-248
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• 2008

A thermal index which considers metabolic heat generation of human body is proposed for operational forecasting. The new thermal index, Perceived Temperature (PT), is forecasted using Weather Research and Forecasting (WRF) mesoscale model and validated. Forecasted PT shows the characteristics of diurnal variation and topographic and latitudinal effect. Statistical skill scores such as correlation, bias, and RMSE are employed for objective verification of PT and input meteorological variables which are used for calculating PT. Verification result indicates that the accuracy of air temperature and wind forecast is higher in the initial forecast time, while relative humidity is improved as the forecast time increases. The forecasted PT during 2007 summer is lower than PT calculated by observation data. The predicted PT has a minimum Root-Mean-Square-Error (RMSE) of $7-8^{\circ}C$ at 9-18 hour forecast. Spatial distribution of PT shows that it is overestimated in western region, while PT in middle-eastern region is underestimated due to strong wind and low temperature forecast. Underestimation of wind speed and overestimation of relative humidity have caused higher PT than observation in southern region. The predicted PT from the mesoscale model gives appropriate information as a thermal index forecast. This study suggests that forecasted PT is applicable to the prediction of health warning based on the relationship between PT and mortality.

• 대한공간정보학회지
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• 제25권1호
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• pp.3-8
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• 2017

본 연구에서는 앙상블 중규모기후모델 weather research and forecasting(WRF)를 이용하여 2045년부터 2054년까지 21세기 중반의 기후변화에 대한 우리나라 미래 풍력자원 지도를 제작하였고 월별, 시간대별 자원변화를 검토하였다. 분석결과, 한반도상에서 강한 몬순 순환으로 인해 뚜렷한 월별 시공간 변동성이 해륙풍에 의한 시간대별 변동성보다 컸다. 풍력자원이 큰 강풍지역은 월마다 지역마다 다르게 나타났다. 즉 겨울철 북서계절풍(여름철 남서계절풍)이 주풍일 때 각각 강원산간과 해상 그리고 남서해안에서 자원이 많을 것으로 전망되었다. 최대풍과 최소풍은 1월, 9월에 각각 나타날 것으로 전망되었고, 시간대별로 내륙과 산간은 일중편차가 컸지만 연안지역은 편차가 작을 것으로 전망되었다. 이는 현재기후에 대한 기존분석결과와는 다소 차이가 있는 것으로, 이 연구에서 생산된 미래 풍력자원 지도는 향후 기후 변화 가능성이 큰 지역의 시공간적 풍황을 감안하여 풍력단지 입지 선정 및 풍력운영을 위한 장기계획 마련에 있어서 유용한 자료가 되리라 기대된다.

• 대기
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• 제31권1호
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• pp.17-28
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• 2021

We investigated the impact of domain size on the simulated summer precipitation over the Korean Peninsula using the Weather Research and Forecasting (WRF) model. Two different domains are integrated up to 72-hours from 29 June 2017 to 28 July 2017 when the Changma front is active. The domain sizes are adopted from previous RDAPS (Regional Data Assimilation and Prediction System) and current LDAPS (Local Data Assimilation and Prediction System) operated by the Korea Meteorological Administration, while other model configurations are fixed identically. We found that the larger domain size showed better prediction skills, especially in precipitation forecast performance. This performance improvement is particularly noticeable over the central region of the Korean Peninsula. Comparisons of physical aspects of each variable revealed that the inflow of moisture flux from the East China Sea was well reproduced in the experiment with a large model domain due to a more realistic North Pacific high compared to the small domain experiment. These results suggest that the North Pacific anticyclone could be an important factor for the precipitation forecast during the summer-time over the Korean Peninsula.

• 대기
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• 제23권2호
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• pp.161-169
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• 2013

We examine the effects of the sea surface temperature (SST) distribution on heavy snowfall over the Yellow Sea using high-resolution SST products and WRF (Weather Research and Forecasting) model simulations in 30 December 2010. First, we evaluate the model by comparing the simulated and observed fresh snowfall over the Korean peninsula (Ho-Nam province). The comparison shows that the model reproduces the distributions and magnitudes of the observed snowfall. We then conduct sensitivity model simulations where SST perturbations by ${\pm}1.1^{\circ}C$ relative to baseline SST values (averaged SST for $5{\sim}15^{\circ}C$) are uniformly specified over the region of interest. Results show that ${\pm}1.1^{\circ}C$ SST perturbation simulations result in changes of air temperature by $+0.37/-0.38^{\circ}C$, and by ${\pm}0.31^{\circ}C$ hPa for sea level pressure, respectively, relative to the baseline simulation. Atmospheric responses to SST perturbations are found to be relatively linear. The changes in SST appear to perturb precipitation variability accounting for 10% of snow and graupel, and 18% of snowfall over the Yellow Sea and Ho- Nam province, respectively. We find that anomalies of air temperature, pressure, and hydrometeors due to SST perturbation propagate to the upper part of cloud top up to 500 hPa and show symmetric responses with respect to SST changes.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2011년도 정기 학술발표대회
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• pp.172-172
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• 2011

The interaction between land surface and atmosphere is essentially affected by hydrometeorological variables including soil moisture. Accurate estimation of soil moisture at spatial and temporal scales is crucial to better understand its roles to the weather systems. The KLDAS(Korea Land Data Assimilation System) is a regional, specifically Korea peninsula land surface information systems. As other prior land data assimilation systems, this can provide initial soil field information which can be used in atmospheric simulations. For this study, as an enabling high-resolution tool, weather research and forecasting(WRF-ARW) model is applied to produce precipitation data using GFS(Global Forecast System) with GFS embedded and KLDAS soil moisture information as initialization data. WRF-ARW generates precipitation data for a specific region using different parameters in physics options. The produced precipitation data will be employed for simulations of Hydrological Models such as HEC(Hydrologic Engineering Center) - HMS(Hydrologic Modeling System) as predefined input data for selected regional water responses. The purpose of this study is to show the impact of a hydrometeorological variable such as soil moisture in KLDAS on hydrological consequences in Korea peninsula. The study region, Chongmi River Basin, is located in the center of Korea Peninsular. This has 60.8Km river length and 17.01% slope. This region mostly consists of farming field however the chosen study area placed in mountainous area. The length of river basin perimeter is 185Km and the average width of river is 9.53 meter with 676 meter highest elevation in this region. We have four different observation locations : Sulsung, Taepyung, Samjook, and Sangkeug observatoriesn, This watershed is selected as a tentative research location and continuously studied for getting hydrological effects from land surface information. Simulations for a real regional storm case(June 17~ June 25, 2006) are executed. WRF-ARW for this case study used WSM6 as a micro physics, Kain-Fritcsch Scheme for cumulus scheme, and YSU scheme for planetary boundary layer. The results of WRF simulations generate excellent precipitation data in terms of peak precipitation and date, and the pattern of daily precipitation for four locations. For Sankeug observatory, WRF overestimated precipitation approximately 100 mm/day on July 17, 2006. Taepyung and Samjook display that WRF produced either with KLDAS or with GFS embedded initial soil moisture data higher precipitation amounts compared to observation. Results and discussions in detail on accuracy of prediction using formerly mentioned manners are going to be presented in 2011 Annual Conference of the Korean Society of Hazard Mitigation.

• 대기
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• 제21권4호
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• pp.405-414
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• 2011

In this study, the influence of a change in land use on the local weather fields is investigated around the Lake Shihwa area using synthetic land cover data and a high-resolution mesoscale model - the Weather Research and Forecasting (WRF). The default land cover data generally used in the WRF is based on the land use category of the United States Geological Survey (USGS), which erroneously presents most land areas of the Korean Peninsula as savannas. To revise such a fault, a multi-temporal land cover data, provided by the Ministry of Environment of Korea, was employed to generate a land cover map of 2005 subject to the land use in Korea at that time. A new land cover map of 1989, before the construction of the Lake Shihwa, was made based on the 2005 map and the Landsat 4-5 TM satellite images of two years. Over the areas where the land use had been changed (e.g., from sea to wetlands, towns, etc.) due to the Lake Shihwa development project, the skin temperature decreased by up to $8^{\circ}C$ in the winter case while increased by as much as $14^{\circ}C$ in the summer case. Changes in the water vapor mixing ratio were mostly affected by advection and topography in both seasons, with considerable increase in the summer case due to continuous sea breeze. Local decrease in water vapor occurred over high land use change areas and/or over downstream of such areas where alteration in wind fields were induced by changes in skin temperature and surface roughness at the areas of land use changes. The albedo increased by about 0.1% in the regions where sea was converted into wetland. In the regions where urban areas were developed, such as Songdo New Town and Incheon International Airport, the albedo increased by up to 0.16%.

• 환경영향평가
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• 제27권5호
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• pp.509-520
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• 2018

본 연구에서는 기상조건 변화에 따른 우리나라 $PM_{10}$ 농도변화 범위를 정량적으로 산정하기 위하여, 2010년에서 2014년까지(5년간) 모델의 입력자료인 국내외 배출량을 동일하게 가정하였을 때 기상조건에 따른 우리나라 $PM_{10}$ 농도변화 범위를 분석하였다. 본 분석에 사용된 모델은 WRF(ver.3.8.1)과 CMAQ(ver.5.0.2)이며, 기상 입력자료는 NCEP FNL $1^{\circ}{\times}1^{\circ}$ 자료, 국외 배출량 목록은 MIX 2010, 국내 배출량 목록은 CAPSS 2010을 이용하였다. 모델 모사결과는 2010년의 전국 일평균 $PM_{10}$ 농도에 대해 측정값과 0.82의 R값을 보이며 실제 $PM_{10}$ 농도의 증감경향을 잘 나타냈지만, 모델은 실제 $PM_{10}$ 농도와 비교하여 과소모의 하는 것으로 나타났다. 기상 및 대기질 모델을 통해 모사된 우리나라 연평균 $PM_{10}$ 농도는 기상조건의 변화로 인해 2010년 대비 평균적으로 약 $2.6{\mu}g/m^3$의 농도변화를 나타내었으며, 계절별로는 봄, 여름, 가을, 겨울에 대해 각각 $4.8{\mu}g/m^3$, $1.7{\mu}g/m^3$, $1.7{\mu}g/m^3$, $4.2{\mu}g/m^3$의 표준편차를 나타내며 봄철과 겨울철에 상대적으로 큰 $PM_{10}$ 농도 차이를 나타냈다. 전국 18개 권역을 대상으로한 지역별 분석 결과에서는 기상조건의 변화로 인해 모든 지역에서 연평균 $PM_{10}$ 농도가 $1.0{\mu}g/m^3$ 이상의 표준편차를 나타냈으며, 특히 서울과 경기북부, 경기남부, 강원영서, 충북 지역의 경우 $2.0{\mu}g/m^3$ 이상으로 타 지역에 비해 상대적으로 높은 차이를 나타냈다.

• 대기
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• 제21권4호
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• pp.373-389
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• 2011

This research focuses on the sensitivity of the WRF(Weather Research and Forecasting) Model according to three different land cover data(USGS(United States Geological Survey), MODIS(Moderate Resolution Imaging Spectroradiometer)30s+USGS, and KLC (Korea Land Cover)) for an event of sea breeze, occurred over the Gangwon Yeongdong region on 13 May 2009. Based on the observation, the easterly into Gangneung, due to the sea-breeze circulation, was identified between 1000 LST and 1640 LST. It did not reach beyond the Taebaek Mountain Range and thus the easterly was not observed near Daegwallyeong. On the other hand, the numerical simulations utilizing land cover data of USGS, MODIS30s+USGS, and KLC showed easterlies beyond the Taebaek Mountain Range up to Daegwallyeong. In addition, rather different penetration distances of each easterly, and different timings of beginning and ending of sea breeze were identified among the simulations. The Bias, MAE(Mean Absolute Error) and RMSE(Root Mean Square Error) of the wind from WRF simulation using MODIS30s+USGS land cover data were the least among the simulations particularly over Gangwon Yeongdong coastal area(Sokcho, Gangneung and Donghae), while those of the wind over the Gangwon Mountain area(Daegwallyeong and Jinbu) from the simulation using KLC land cover data were the least among them. The wind field over Gangwon Yeongdong coastal area from the simulation using USGS land cover data was rather poor among them.

• 한국지구과학회지
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• 제32권7호
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• pp.750-760
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• 2011

본 연구에서는 신뢰성 있는 국가표준 지역기후변화 시나리오 생산을 위해 현재기후에 대한 SNURCM과 WRF의 재현성을 검증하였다. 국립기상연구소에서 생산된 HadGEM2-AO 전구자료를 지역기후모형의 경계조건으로 사용하여 CORDEX 규준 하에 28년(1978-2005)간의 장기적분을 수행하였다. 두 모형은 연평균 지표 온도 분포를 관측과의 공간상관계수가 0.98 이상으로 매우 높은 일치성을 나타내었지만, 모형 영역의 북쪽 경계를 중심으로 한랭 편차를 공통적으로 보였다. 강수의 경우 또한 육지 지역을 대상으로 한 관측과의 공간 상관 계수는 SNURCM이 0.85, WRF가 0.79로 나타나 우수한 모의 결과를 보였다. 두 모형에서 모의된 강수 분포는 적도와 중위도 지역 간에 상반되는 특성을 보였다. SNURCM은 WRF에 비교하여 중위도 동아시아 몬순 강수대의 분포를 적도 지역의 강수대보다 상대적으로 잘 모의하였으나, WRF는 그 반대의 결과를 나타내었다. 여름철(JJA) 보다 봄철(MAM)에 과다 모의되었지만 모의된 강수 분포의 일치성은 봄철에 높게 나타났다. 세부영역 별 분석에서 두 모형은 7월 강수 최대 시점과 양을 비교적 정확히 모의하였고, 특히 내륙 지역 강수량의 모의 정확도가 해양에 영향 받는 지역보다 높았다. 모의결과는 한반도 상의 높은 일평균 지표온도일수와 강한 강수일수를 표현하는데 한계를 보였다.

• Wind and Structures
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• 제28권2호
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• pp.129-140
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• 2019

Accurately simulating the wind field of large-scale region, for instant urban areas, the locations of large span bridges, wind farms and so on, is very difficult, due to the complicated terrains or land surfaces. Currently, the regional wind field can be simulated through the combination of observation data and numerical model using observation-nudging in the Weather Research and Forecasting model (WRF). However, the main drawback of original observation-nudging method in WRF is the effects of observation on the surrounding field is fully mathematical express in terms of temporal and spatial, and it ignores the effects of terrain, wind direction and atmospheric circulation, while these are physically unreasonable for the turbulence. For these reasons, a spatial correlation-based observation-nudging method, which can take account the influence of complicated terrain, is proposed in the paper. The validation and comparation results show that proposed method can obtain more reasonable and accurate result than original observation-nudging method. Finally, the discussion of wind field along bridge span obtained from the simulation with spatial correlation-based observation-nudging method was carried out.