• 한국해안·해양공학회논문집
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• 제35권4호
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• pp.67-74
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• 2023

열대성 저기압으로 인한 높은 파도와 폭풍해일은 해안지역에 큰 피해를 준다. 따라서 태풍이 내습하기 전에 정확하게 예측해야 하는데, 기상 강제력은 예측에 중요한 요소이다. 본 연구는 정확한 폭풍해일 및 파랑예측에 요구되는 기상 강제력을 위한 개선방안을 제시한다. 2016년 남해안을 강타한 태풍 차바를 사례연구로 하여, 기상예측모델(MPAS)로 태풍 트랙 및 기상 강제력, 즉, 기상장을 예측했다. 예측된 MPAS 태풍 트랙 정보를 기반으로 한 태풍의 대칭형 및 비대칭형 파라미터 와류 모델을 이용하여 기상 강제력을 생성하는 한편, 베스트 트랙 기반 동일 한 파라미터 모델을 이용하여 기상 강제력을 생성하여, 둘을 비교했다. 또한, MPAS 예측 태풍 트랙 정보 기반 대칭형/비대칭형 와류 파라미터 모델에서 생성된 기상장은 MPAS에서 예측한 기상장과 블렌딩하여 예측기상장을 만들었다. 이렇게 제작된 MPAS 기반 forecast 기상장 4종 및 베스트 트랙 기반 hindcast 기상장 2종을 ADCIRC+SWAN ADCIRC+SWAN에 입력하여 남해안의 파랑 및 폭풍해일을 예측/재현하고 관측치와 비교·검증했다. MPAS 기반 forecast 기상장을 이용하여 예측된 폭풍해일과 파랑은 관측치와 거의 일치했으며, 베스트 트랙을 사용하여 재현한 결과와도 견줄 만했다. 유의파고는, 6종의 기상장을 이용한 실험에서 MPAS 예측 태풍 트랙 기반 대칭형 와류 파라미터 모델로 생성된 기상장과 MPAS 예측 기상장을 블렌딩한 실험이 예측 정확도가 높았으나, 비대칭형 와류 파라미터 모델과 블렌딩을 사용한 경우보다 약간 높은 정도였다. 폭풍해일은, MPAS 예측 태풍 트랙을 이용한 비대칭형 와류 파라미터 모델에서 생성된 기상장을 이용한 실험이 예측 정확도가 높았다. 폭풍해일과 파랑을 정확하게 예측하기 위해서는, 정확한 태풍 트랙 정보와 이 정보가 반영된 비대칭형 와류가 고려된 기상장, 이 태풍 트랙을 생산한 기상장이 필요한 것을 볼 수 있다.

• 한국대기환경학회지
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• 제33권6호
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• pp.554-569
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• 2017

Sensitivity analysis on $PM_{10}$ forecasting simulations was carried out by using two different initial and boundary conditions of meteorological fields: NCEP/FNL (National Centers for Environmental Prediction/Final Analysis) reanlaysis data and NCEP/GFS (National Centers for Environmental Prediction/Global Forecast System) forecasting data, and the comparisons were made between two different simulations. The two results both yielded lower $PM_{10}$ concentrations than observations, with relatively lower biased results by NCEP/FNL than NCEP/GFS. We explored the detailed individual meteorological variables to associate with $PM_{10}$ prediction performance. With the results of NCEP/FNL outperforming GFS, our conclusion is that no particular significant bias was found in temperature fields between NCEP/FNL and NCEP/GFS data, while the overestimated wind speed by NCEP/GFS data influenced on the lower $PM_{10}$ concentrations simulation than NCEP/FNL, by decreasing the duration time of high-$PM_{10}$ loaded air mass over both coastal and metropolitan areas. These comparative characteristics of FNL against GFS data such as maximum 3~4 m/s weaker wind speed, $PM_{10}$ concentration control with the highest possible factor of 1.3~1.6, and one or two hour difference of peak time for each case in this study, were also reflected into the results of statistical analysis. It is implying that improving the surface wind speed fluctuation is an important controlling factor for the better prediction of $PM_{10}$ over Korean Peninsula.

• 대기
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• 제16권4호
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• pp.359-370
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• 2006

Terrain height variance spectra for the Korean mountain region are calculated in order to determine an adequate grid size required to resolve terrain forcing on mesoscale model simulation. One-dimensional spectral analysis is applied to specifically the central-eastern part of the Korean mountain region, where topographical-scale forcing has an important effect on mesoscale atmospheric flow. It is found that the terrain height variance spectra in this mountain region has a wavelength dependence with the power law exponents of 1.5 at the wavelength near 30 km, but this dependence is steeply changed to 2.5 at the wavelength less than 30 km. For the adequate horizontal grid size selection on mesoscale simulation two-dimensional terrain height spectral analysis is also performed. There is no directionality within 50% of spectral energy region, so one-dimensional spectral analysis can be reasonably applied to the Korea Peninsula. According to the spectral analysis of terrain height variance, the finer grid size which is higher than 6 km is required to resolve a 90% of terrain variance in this region. Numerical simulation using WRF (Weather Research and Forecasting Model) was performed to evaluate the effect of different terrain resolution in accordance with the result of spectral analysis. The simulated results were quantitatively compared to observations and there was a significant improvement in the wind prediction across the mountain region as the grid space decreased from 18 km to 2 km. The results will provide useful guidance of grid size selection on mesoscale topographical simulation over the Korean mountain region.

• 대기
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• 제26권3호
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• pp.445-459
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• 2016

Air temperature deviation (ATD) is one of major indicators to represent spatial distribution of urban heat island (UHI), which is induced from the urbanization. The purpose of this study is to evaluate the accuracy of air temperature deviation about Climate Analysis Seoul (CAS) workbench, which had developed by National Institute Meteorological Science and TU Berlin. Comparison and correlation analysis for CAS ATD including meso-scale air temperature deviation, local-scale air temperature deviation, total air temperature deviation, surface heat flux deviation, cold air production deviation among meso-scale numerical modelling variable in 'Seoul Region', micro-scale numerical modelling in 'Detail Region', and CAS workbench variable using observation data in ground stations. Comparison between night time OBS ATD and CAS ATD show that have most close values. Most of observations ($dT_{max}$ and $dT_{min}$) have highly positive ($dT_{SHP}$, $dT_{CA}$, MD, TD, $f_{BS}$, $f_{US}$, $f_{WS}$, $h_B$) and negative ($f_{VS}$, $f_{TV}$, $h_V$, Z) correlations. However, CAS workbench needs further improvement of both observational framework and analytical framework to resolve the problems; (1) night time OBS ATD of has closer values in compare with at high rise mountain area and (2) correlations are very dependable to meteorological scale.

• 신재생에너지
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• 제9권2호
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• pp.15-22
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• 2013

The solar energy are an infinite source of energy and a clean energy without secondary pollution. The global solar energy reaching the earth's surface can be calculated easily according to the change of latitude, altitude, and sloped surface depending on the amount of the actual state of the atmosphere and clouds. The high-resolution solar-meteorological resource map with 1km resolution was developed in 2011 based on GWNU (Gangneung-Wonju National University) solar radiation model with complex terrain. The very high resolution solar energy map can be calculated and analyzed in Seoul and Eunpyung with topological effect using by 1km solar-meteorological resources map, respectively. Seoul DEM (Digital Elevation Model) have 10m resolution from NGII (National Geographic Information Institute) and Eunpyeong new town DSM (Digital Surface Model) have 1m spatial resolution from lidar observations. The solar energy have small differences according to the local mountainous terrain and residential area. The maximum bias have up to 20% and 16% in Seoul and Eunpyung new town, respectively. Small differences are that limited area with resolutions. As a result, the solar energy can calculate precisely using solar radiation model with topological effect by digital elevation data and its results can be used as the basis data for the photovoltaic and solar thermal generation.

• 대기
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• 제20권3호
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• pp.273-286
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• 2010

The northeast part of China(hereafter Manchuria) is one of Asian dust source regions along with Gobi, Inner Mongolia and Loess Plateau. In this study, a geographical survey over the area was carried out to determine its soil characteristics in June 2009. It revealed that some parts of the area, especially near Keerchin desert, consist of alkali clay soil mixed up with sand. Manchuria, where is a vast cornfield, can be a potential source region of Asian dust from fall to following spring after harvesting. The frequency of Asian dust over the region from 1996 to 2009 was examined using 3-hourly GTS SYNOP data and it showed that the occurrence of Asian dust over the region is high in the springtime. It was also revealed that snow cover is the key parameter affecting on the frequency through the analysis of NCEP reanalysis data. To scrutinize the path and structure of Asian dust from Manchuria, the event on 3~4 April 2008 and 25 January 2010 were intensively investigated with regard to features of synoptic weather patterns, satellite imagery, airstream, naked eye-observations, concentrations of PM10, 2.5 and 1.0. For this case, the Asian dust from the area reached to Korea less than a day. However, the duration time of the dust in Korea was short (< 7 hours). The average of hourly PM10 reached up to $340{\mu}g/m^{3}$ at Baengnyeondo during the period. The high PM2.5 and PM1.0 concentrations were also observed at several sites in Korea, indicating that air pollutants could be transported along with the dust.

• 대기
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• 제30권1호
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• pp.17-30
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• 2020

KMA performed the special observation program to provide information about severe weather and to monitor typhoon PRAPIROON using the ship which called the Gisang 1 from 29 June 2018 to 4 July 2018 (UTC). For this period, upper-air was observed 21 times with 6 hour intervals using rawinsonde in the Gisang 1. We investigated the impact of upper-air observation data from the Gisang 1 on the performance of the operational convective scale model (we called LDAPS). We conducted two experiments that used all observation data including upper-air observation data from the Gisang 1 (OPER) and without it (EXPR). For a typhoon PRAPIROON case, track forecast error of OPER was lower than EXPR until forecast 24 hours. The intensity forecast error of OPER for minimum sea level pressure was lower than EXPR until forecast 12 hours. The intensity forecast error of OPER for maximum wind speed was mostly lower than EXPR until forecast 30 hours. OPER showed good performance for typhoon forecast compared with EXPR at the early lead time. Two precipitation cases occurred in the south of the Korean peninsula due to the impact of Changma on 1 July and typhoon on 3 July. The location of main precipitation band predicted from OPER was closer to observations. As assimilating upper-air data observed in the Gisang 1 to model, it showed positive results in typhoon and precipitation cases.

• 한국해양공학회지
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• 제35권4호
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• pp.273-286
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• 2021

In recent years, as human casualties and property damage caused by hazardous waves have increased in the East Sea, precise wave prediction skills have become necessary. In this study, the Simulating WAves Nearshore (SWAN) third-generation numerical wave model was calibrated and optimized to enhance the accuracy of winter storm wave prediction in the East Sea. We used Source Term 6 (ST6) and physical observations from a large-scale experiment conducted in Australia and compared its results to Komen's formula, a default in SWAN. As input wind data, we used Korean Meteorological Agency's (KMA's) operational meteorological model called Regional Data Assimilation and Prediction System (RDAPS), the European Centre for Medium Range Weather Forecasts' newest 5th generation re-analysis data (ERA5), and Japanese Meteorological Agency's (JMA's) meso-scale forecasting data. We analyzed the accuracy of each model's results by comparing them to observation data. For quantitative analysis and assessment, the observed wave data for 6 locations from KMA and Korea Hydrographic and Oceanographic Agency (KHOA) were used, and statistical analysis was conducted to assess model accuracy. As a result, ST6 models had a smaller root mean square error and higher correlation coefficient than the default model in significant wave height prediction. However, for peak wave period simulation, the results were incoherent among each model and location. In simulations with different wind data, the simulation using ERA5 for input wind datashowed the most accurate results overall but underestimated the wave height in predicting high wave events compared to the simulation using RDAPS and JMA meso-scale model. In addition, it showed that the spatial resolution of wind plays a more significant role in predicting high wave events. Nevertheless, the numerical model optimized in this study highlighted some limitations in predicting high waves that rise rapidly in time caused by meteorological events. This suggests that further research is necessary to enhance the accuracy of wave prediction in various climate conditions, such as extreme weather.

• 통합자연과학논문집
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• 제17권1호
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• pp.1-12
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• 2024

Many abnormal climate events are occurring around the world. The cause of abnormal climate is related to temperature. Factors that affect temperature include excessive emissions of carbon and greenhouse gases from a global perspective, and air circulation from a local perspective. Due to the air circulation, many abnormal climate phenomena such as abnormally high temperature and abnormally low temperature are occurring in certain areas, which can cause very serious human damage. Therefore, the problem of abnormal temperature should not be approached only as a case of climate change, but should be studied as a new category of climate crisis. In this study, we proposed a model for the classification of abnormal temperature using random forests based on various meteorological data such as longitudinal observations, yellow dust, ultraviolet radiation from 2018 to 2022 for each region in Korea. Here, the meteorological data had an imbalance problem, so the imbalance problem was solved by oversampling. As a result, we found that the variables affecting abnormal temperature are different in different regions. In particular, the central and southern regions are influenced by high pressure (Mainland China, Siberian high pressure, and North Pacific high pressure) due to their regional characteristics, so pressure-related variables had a significant impact on the classification of abnormal temperature. This suggests that a regional approach can be taken to predict abnormal temperatures from the surrounding meteorological environment. In addition, in the event of an abnormal temperature, it seems that it is possible to take preventive measures in advance according to regional characteristics.

• 대기
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• 제31권2호
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• pp.229-240
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• 2021

본 연구에서는 기상청에서 2018년부터 운영 중인 전지구 해양자료동화시스템 GODAPS에 대하여 소개하였으며, 2015년 2월부터 2016년 1월까지 일년간의 실험 수행을 통한 결과를 분석하여 이 시스템의 특성을 살펴보았다. GODAPS는 크게 해양-해빙 모델과 3차원 변분법 기반의 자료동화 시스템으로 구성되어 있고, 전지구적으로 수집된 현장 및 위성 관측자료를 자료동화하여 매일 1회 분석장과 예측장을 생산한다. 이때 해수면온도, 수온과 염분 프로파일, 해수면고도 변이, 그리고 해빙농도 관측자료를 자료동화한다. 분석증분 및 배경장/분석장으로부터의 관측증분에 대한 분석, 자료동화를 적용하지 않은 실험과의 비교 등을 통해 GODAPS 자료동화 결과를 비교검증하였다. 자료동화는 관측자료들을 효과적으로 활용하고 있었으며, 전지구 규모에서 편차를 줄인 분석장과 예측장을 생산하고 있는 것으로 나타났다. 이외에도, 변동성이 강한 중위도 해역의 쿠로시오와 걸프만 해류의 중규모 현상을 재현하는데 있어서도 결정적인 영향을 미치는 것으로 확인하였다. 해양초기장을 향상시키기 위해서는 모델과 자료동화 기술의 개발과 더불어, 다양한 관측자료를 활용하는 것이 중요하다. 하지만, 현업에서 활용할 수 있는 해양관측자료는 한계가 있으며, 따라서 가용한 자료를 자료동화 과정에 포함시키는 노력이 요구된다. 수온에 비해 염분의 경우 상대적으로 관측자료가 부족한데, 최근에는 SMAP (Soil Moisture Active Passive) 등 인공위성을 활용한 표층 염분자료가 제공되고 있으며, 기상청에서도 자료동화 과정에 독립적인 위성 염분자료를 활용한 분석장 검증 및 자료동화에 직접적용하는 연구를 추진하고 있다. 특히, 표층 염분의 자료동화를 통해 열대해역의 혼합층 깊이가 개선되고, 결과적으로 기후예측성을 향상시키는 연구결과(Hackert et al., 2020) 등을 고려할 때, 향후 위성관측 표층염분의 자료동화는 기후예측 분야에 있어서 점차 중요해질 것으로 판단된다. 본 연구의 실험결과에서도 GODAPS의 염분 관측증분 오차가 표층에서 상대적으로 크게 나타나고 있어, 해양초기장의 정확성을 높이고 나아가 기후예측성을 높이는데 위성 염분자료가 효과적으로 사용될 수 있을 것으로 기대된다.