• 한국지구과학회지
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• 제35권1호
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• pp.41-53
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• 2014

겨울철 동해안 강수 현상에 대한 규명을 위하여 라디오존데를 활용한 특별관측을 2012년 1월 5일부터 2월 29일까지 실시하였고, 이 연구는 대기의 불안정을 나타내는 다양한 변수를 활용하여 강수 사례의 분석을 수행하였다. 그 결과, 강수가 발생할 때 지표면(1000 hPa)에서 중층(약 750 hPa)까지의 상당온위가 증가하는 것을 볼 수 있었고, 이러한 대기층(1000~750 hPa)은 불안정을 일으키기에 충분한 수준의 수증기를 함유하고 있었다. 대류가용잠재에너지의 시간적인 변화를 살펴본 결과 강수가 발생하였을 때 증가하는 것을 볼 수 있었고, 연직바람쉬어의 경우에서도 대류가용잠재에너지와 마찬가지로 강수 기간 동안 상승하여 일정수준 이상의 값을 유지하는 것을 확인할 수 있었다. 강수에 따른 대기 구조의 상세한 분석을 위하여 지상 원격 탐사 자료와 지상 관측 자료를 활용하여 분석을 수행하였다. 또한 가강수량과 바람벡터를 이용하여 가강수량플럭스를 계산하였다. 가강수량플럭스와 강수량은 북동풍 계열의 바람이 발생하였을 때 높은 관계성을 보였다. 그 결과 동해안영역에서 발생하는 강수 현상에서는 풍계와 같은 역학적인 작용의 이해가 중요한 것으로 판단되었다.

• 대기
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• 제34권2호
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• pp.139-151
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• 2024

The Yeongdong region has suffered from severe snowstorms and the relevant damage such as traffic accidents on slippery roads, and the collapse of greenhouses and temporary buildings. While a lot of research on snowfall has been conducted, the detailed study of snow crystals' phase and habit through intensive observations and the relevant microphysical analysis is still lacking. Therefore, a snowflake camera, PARSIVEL, and intensive radiosonde soundings were utilized to investigate phase and habit changes in solid precipitation. Two remarkable episodes of phase and habit changes were selected such as 19 March 2022 and 15 February 2023. Both events occurred in the synoptic condition of the High in the north and the Low passing by the south, which was accompanied by rapid temperature cooling below 2.5 km. During the events of a short period between 3 to 6 hours, the temperature at 850 hPa decreased by about 4 to 6℃. This cooling led to a change in the main habit of snow particles from riming to aggregate, identified with both MASC and PARSIVEL. Meanwhile, the LDAPS model analyses do not successively represent the rapid cooling and short-term variations of solid precipitation, probably by virtue of overestimating low-level equivalent potential temperature during these periods. The underlying causes of these the low-level temperature variations within 6 hours, still remain unclear. It might be associated with mesoscale orographic phenomenon due to the mountains and East Sea effects, which certainly needs an intensive and comprehensive observation campaign.

• 방사선산업학회지
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• 제17권3호
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• pp.299-307
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• 2023

Given that toxic substances are diffused by the various movements of the atmosphere, it is very important to evaluate the risks associated with this phenomenon. When analyzing the behavioral characteristics of these atmospheric diffusion models, the main input data are the wind speed and wind direction among the meteorological data. In particular, it is known that a certain wind direction occurs in summer and winter in Korea under the influence of westerlies and monsoons. In this study, synoptic meteorological observation data provided by the Korea Meteorological Administration were analyzed from January 1, 2012 to the end of August of 2022 to understand the regional wind characteristics of nuclear power plants and surrounding areas. The selected target areas consisted of 16 weather stations around the Hanbit, Kori, Wolsong, Hanul, and Saeul nuclear power plants that are currently in operation. The analysis was based on the temperature, wind direction, and wind speed data at those locations. Average, maximum, minimum, median, and mode values were analyzed using long-term annual temperature, wind speed, and wind direction data. Correlation coefficient values were also analyzed to determine the linear relationships among the temperature, wind direction, and wind speed. Among the 16 districts, Uljin had the highest wind speed. The median wind speed values for each region were lower than the average wind speed values. For regions where the average wind speed exceeds the median wind speed, Yeongju, Gochang, Gyeongju, Yeonggwang, and Gimhae were calculated as 0.69 m s^-1, 0.54m s^-1, 0.45m s^-1, 0.4m s^-1, and 0.36m s^-1, respectively. The average temperature in the 16 regions was 13.52 degrees Celsius; the median temperature was 14.31 degrees and the mode temperature was 20.69 degrees. The average regional temperature standard deviation was calculated and found to be 9.83 degrees. The maximum summer temperatures were 39.7, 39.5, and 39.3 in Yeongdeok, Pohang, and Yeongcheon, respectively. The wind directions and speeds in the 16 regions were plotted as a wind rose graph, and the characteristics of the wind direction and speed of each region were investigated. It was found that there is a dominant wind direction correlated with the topographical characteristics in each region. However, the linear relationship between the wind speed and direction by region varied from 0.53 to 0.07. Through this study, by evaluating meteorological observation data on a long-term synoptic scale of ten years, regional characteristics were found.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.569-573
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• 2005

Land surface temperature(LST) is one of the key parameters in physics and meteorology of land-surface processes on regional and global scales. Urban Heat Island(UHI), a meteorological phenomenon by which the air temperature in an urban area increases beyond that in the suburbs, grows with the progress of urbanization. Satellite remote sensing has been expected to be effective for obtaining thermal information of the earth's surface with a high resolution. The main purpose of this study is to produce LST map of Cheongju and to analyze the spatial distributions of surface heat fluxes in urban areas. This study, taking Cheongju as the study area, aims to examine relationship between vegetation cover rates and surface temperature, and to clarify a method for calculation surface temperature with Landsat TM thermal images.

• 한국농림기상학회지
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• 제24권2호
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• pp.95-114
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• 2022

본 연구는 MFOS라 명명한 다중센서 기반의 서리 관측 시스템의 고안 및 설치를 통해 서리의 자동 관측 가능성 및 실제 서리 발생 시 관련 영상 자료를 제시하였다. MFOS의 구성은 RGB 카메라, 열화상 카메라, LWS이며, 각 장비들은 서로 상보적인 역할을 수행한다. 서리 발생 전 장비의 시험 운영을 통해, 무강수 사례인 경우 높은 상대습도를 유지할 때 LWS의 전압값은 증가하였고, 특히 주변의 농수로로 인해 높은 상대습도가 유지되는 가평군 관측지에서 크게 증가하였다. RGB 카메라 이미지에서는 일출 전과 일몰 후에 LWS와 지표면을 관측할 수 없었으나 나머지 시간에 대해서는 가능하였다. 강수 사례의 경우 강수 기간 동안 LWS의 전압값은 급격하게 증가하였고, 강수 종료 후 감소하였다. RGB 카메라 이미지는 강수 현상과 상관없이 LWS와 지표면을 관측하였다. 반면, 열화상 카메라의 경우 강수 현상으로 인해 이미지 촬영은 되었지만 LWS와 지표면을 관측하지 못했다. 실제 서리가 발생한 사례의 자료를 통해, LWS의 전압값이 서리에 해당하는 범위보다 높더라도 RGB 카메라가 서리의 지표면 및 장비 표면 발생을 관측할 수 있는 것으로 나타났다.

• 대기
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• 제17권2호
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• pp.147-157
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• 2007

A weekend effect has been investigated in diurnal temperature range (DTR) for Seoul in Korea using 50-year (1955 ~ 2005) surface measurements of maximum and minimum temperatures, and particle mass concentrations (PM10). The minimum temperature increases by 0.42K per decade, 2 times faster than the maximum temperature during 1955 to 2005, for rapid urbanization has occurred in Seoul. The weekend effect, which is defined as the DTR for Sunday minus the average DTR for Tuseday through Thursday, can be as large as +0.08 K for the recent 20-year period relative to 0.01K for 1955 to 1975. Especially the wintertime DTR tends to have a remarkable positive weekend effect (+0.17K), that is, larger DTR on Sunday compared to weekdays, which seems to be associated with increased maximum temperature and thus an increase in DTR. This result could be explained by relative differences in PM10 concentration between Sunday and weekdays (Tuesday through Thursday), such that PM10 concentration on Sundays appears to be systematically lower about 12% than on weekdays. The annually average weekend DTR increases by 0.2K with $10{\mu}gm^{-3}$ decrease in PM10 concentration in comparison with weekdays. The results could be possible evidence of an anthropogenic link to DTR, one of climate important indicators, since no meteorological phenomenon is supposed to occur over a 7 day cycle.

• 한국환경과학회지
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• 제18권5호
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• pp.489-499
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• 2009

In an effort to examine the Regional Atmospheric Modeling System (RAMS ver. 4.3) to the initial meteorological input data, detailed observational data of NOAA satellite SST (Sea Surface Temperature) was employed. The NOAA satellite SST which is currently provided daily as a seven-day mean value with resolution of 0.1 $^{\circ}$ grid spacing was used instead of the climatologically derived monthly mean SST using in RAMS. In addition, the RAMS SST data must be changed new one because it was constructed in 1993. For more realistic initial meteorological fields, the NOAA satellite SST was incorporated into the RAMS-preprocess package named ISentropic Analysis package (ISAN). When the NOAA SST data was imposed to the initial condition of prognostic RAMS model, the resultant performance of near surface atmospheric fields was discussed and compared with that of default option of SST. We got the good results that the new SST data was made in a standard RAMS format and showed the detailed variation of SST. As the modeling grid became smaller, the SST differences of the NOAA SST run and the RAMS SST43 (default) run in diurnal variation were very minor but this research can apply to further study for the realistic SST situation and the development in predicting regional atmospheric field which imply the regional circulation due to differential surface heating between sea and land or climatological phenomenon.

• 대기
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• 제20권4호
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• pp.399-414
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• 2010

Sand and dust storm in East Asia, so called Asian dust, is a seasonal meteorological phenomenon. Mostly in spring, dust particles blown into atmosphere in the arid area over northern China desert and Manchuria are transported to East Asia by prevailing flows. An Asian dust event occurred on 6-8 May 2007 is chosen to investigate how sensitive the Asian dust transport forecast to the initial condition uncertainties and to interpret the characteristics of sensitivity structures from the viewpoint of dynamics and predictability. To investigate the forecast sensitivities to the initial condition, adjoint sensitivities that calculate gradient of the forecast aspect (i.e., response function) with respect to the initial condition are used. The forecast aspects relevant to Asian dust transports are dry energy forecast error and lower tropospheric pressure forecast error. The results show that the sensitive regions for the dry energy forecast error and the lower tropospheric pressure forecast error are initially located in the vicinity of the trough and then propagate eastward as the surface low system moves eastward. The vertical structures of the adjoint sensitivities for the dry energy forecast error are upshear tilted structures, which are typical adjoint sensitivity structures for extratropical cyclones. Energy distribution of singular vectors also show very similar structures with the adjoint sensitivities for the dry energy forecast error. The adjoint sensitivities of the lower tropospheric pressure forecast error with respect to the relative vorticity show that the accurate forecast of the trough (or relative vorticity) location and intensity is essential to have better forecasts of the Asian dust event. Forecast error for the atmospheric circulation during the dust event is reduced 62.8% by extracting properly weighted adjoint sensitivity perturbations from the initial state. Linearity assumption holds generally well for this case. Dynamics of the Asian dust transport is closely associated with predictability of it, and the improvement in the overall forecast by the adjoint sensitivity perturbations implies that adjoint sensitivities would be beneficial in improving the forecast of Asian dust events.

• 한국습지학회지
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• 제19권1호
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• pp.122-131
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• 2017

위성자료는 수집이 용이할 뿐만 아니라, 지점에서 관측된 자료에 비해 보다 광범위한 현상을 표현함으로써 보다 많은 연구를 활성화하고 발전시키는데 이바지하고 있다. 하지만 한반도와 같이 지형이 복잡하고 균일하지 않은 지역에서는 연구 목적이나 방법에 적절한 공간해상도의 자료를 산정하는 것이 매우 중요하다. 본 연구에서는 정지궤도 위성인 천리안 위성의 GOCI와 MI에서 관측되는 자료를 융합함으로써 4 km에서 500m 까지 상세화하여 고해상도의 지표면 온도 자료를 생산하였다. 이를 12개 지점에서 관측된 ASOS 자료들과의 통계적 분석을 통해 그 활용성을 검증하였다. 그 결과 대부분의 지점에서 오차는 감소하고, 상관도가 증가하는 것을 볼 수 있었으며, 공간 분포 분석에서는 크게 비슷한 경향을 띄고 있으면서도 복잡한 지형을 보다 잘 표현하는 것으로 나타났다. 따라서 본 연구를 통해 상세화 된 한반도의 지표면 온도 자료가 천리안 위성의 활용 범위를 보다 확장하고 다양한 연구의 기반이 될 수 있을 것으로 기대된다.

• 한국농공학회논문집
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• 제57권1호
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• pp.37-45
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• 2015

Recent droughts in South Korea have had large economic and environmental impacts across the country. Changes in rainfall and hydrologic patterns due to climate change can potentially increase the occurrence of extreme droughts and affect the future availability of water resources. Therefore, it is necessary to evaluate drought vulnerability for water resources planning and management, and identify the appropriate mitigation actions to conduct a drought risk analysis in the context of climate change. The objective of this study is changes in the temporal trends of drought characteristics in South Korea to examine drought impacts under climate change. First, the changes of drought occurrence were analyzed by applying the Standardized Precipitation Evapotranspiration Index (SPEI) for meteorological data on 54 meteorological stations, and were analyzed for the past 30 years (1981-2010), and Representative Concentration Pathways (RCP) climate change scenarios (2011-2100). Second, the changes on the temporal trends of drought characteristics were performed using run theory, which was used to compare drought duration, severity, and magnitude to allow for quantitative evaluations under past and future climate conditions. These results show the high influence of climate change on drought phenomenon, and will contribute to water resources management and drought countermeasures to climate change.