• 한국환경과학회지
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• 제16권10호
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• pp.1157-1167
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• 2007

In an effort to interpret the characteristics of fine particle concentrations in Busan, time variations of hourly monitored concentrations $PM_{10}$ (Particulate Matter with aerodynamic Diameter ${\le}10\;{\mu}m$) in Busan are analyzed for the period from 2000 to 2005. The characteristics of aerosol second generation formation process is also interpreted qualitatively, by using the statistical analysis of the meteorological variables including temperature, wind speed, and relative humidity. The result shows some significant annual, seasonal, weekly and diurnal variations of $PM_{10}$ concentrations. In particular, seasonal(i.e., spring) variations are governed by frequency of yellow sand events even for the non-yellow sand cases where yellow-sand days are eliminated in our analysis. However, in seasonal variation, summer season predominate lower $PM_{10}$ concentrations due to the frequent precipitation, and weekly and diurnal variations are both found to be reflecting the emission rate from traffic amount. Correlation coefficients between $PM_{10}$ concentration and meterological variables for non-yellow sand days show overall negative correlation with visibility, wind speed, cloud amounts, and relative humidity. However for non-precipitation days, during non-yellow sand period positive correlation are found clearly with relative humidity, suggesting the importance of secondary aerosol formation in Busan that can be achieved by both homogeneous aerosol formation and heterogeneous transformations resulting from hygroscopic aerosol characteristics.

• 천문학논총
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• 제30권2호
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• pp.439-442
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• 2015

We observed multiple CO transition lines and the HCN(1-0) line at ~ 1" (~ 34 pc) or higher resolution toward the Seyfert 2 nucleus of M51 using the IRAM Plateau de Bure Interferometer (PdBI) and the Submillimeter Array (SMA). All the images show very similar overall molecular gas distribution; there are two discrete clouds at the eastern and western sides of the nucleus, and the western cloud exhibits an elongated distribution and velocity gradient along the radio jet. In addition, high HCN(1-0)/CO(1-0) brightness temperature ratios of about unity have been observed, especially along the radio jet, similar to those observed in shocked molecular gas in our Galaxy. This strongly indicates that the molecular gas along the jet is shocked, that the radio jet and the molecular gas are interacting, and the jet is entraining both diffuse (CO) and dense (HCN) molecular gas outwards from the circumnuclear region. This is the first clear imaging of the outflowing molecular gas entrained by the AGN jet, and showing the detailed physical status of outflowing molecular gas. Since a relatively high HCN(1-0)/CO(1-0) ratio has been observed in the high velocity wing of ultraluminous infrared galaxies, it can also be explained by a similar mechanism to those we describe here.

• 천문학회보
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• 제37권2호
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• pp.111.2-111.2
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• 2012

We observed an Ellerman bomb(EB) and its associated surge using the Fast Imaging Solar Spectrograph(FISS) and the broadband TiO filter of the 1.6 meter New Solar Telescope at Big Bear Solar Observatory. As is well-known, the EB appears as a feature that is very bright at the far wings of the H alpha line. The lambdameter method applied to these wings indicates that the EB is blue-shifted up to 6km/s in velocity. In the photospheric level below the EB, we see rapidly growing "granule-like" feature. The transverse velocity of the dark lane at the edge of the "granule" increased with time as reached a peak of 6km/s, at the time of the EB's occurrence. The surge was seen in absorption and varied rapidly both in the H alpha and the Ca II 8542 line. It originated from the Ellerman bomb, and was impulsively accelerated to 20km/s toward us(blueshift). Then the velocity of the surge gradually changed from blueshift of 20km/s to redshift of 40km/s. By adopting the cloud model, we estimated the temperature of the surge material at about 27000K and the non-thermal velocity at about 10km/s. Our results shed light on the conventional idea that an EB results from the magnetic reconnection of an emerging flux tube and pre-existing field line.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.721-727
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• 2002

Precipitation evapotranspiration and runoff are three key parameters of regional water balance. Problems exist in the traditional methods for calculating such factors , such as explaining of the geographic rationality of spatial interpolating methods and lacking of enough observation stations in many important area for bad natural conditions. With the development of modern spatial info-techniques, new efficient shifts arose for traditional studies. Guided by theories on energy flow and materials exchange within Soil-Atmosphere-Plant Continuant (SPAC), retrieval models of key hydrological parameters were established in the Yellow River basin using CMS-5 and FengYun-2 meteorological satellite data. Precipitation and evapotranspiration were then estimated: (1) Estimating tile amount of solar energy that is absorbed by the ground with surface reflectivity, which is measured in the visible wavelength band (VIS): (2) Assessing the partitioning of the absorbed energy between sensible and latent heat with the surface temperature, which was measured in the thermal infrared band (TIR), the latent heat representing the evapotranspiration of water; (3) Clouds are identified and cloud top levels are classified using both VIS and TIR data. Hereafter precipitation will be calculated pixel by pixel with retrieval model. Daily results are first obtained, which are then processed to decade, monthly and yearly products. Precipitation model has been has been and tested with ground truth data; meanwhile, the evapotranspiration result has been verified with Large Aperture Scintillometry (LAS) presented by Wageningen University of the Netherlands. Further studies may concentrate on the application of models, i.e., establish a hydrological model of the Yellow river basin to make the accurate estimation of river volume and even monitor the whole hydrological progress.

• 대한원격탐사학회지
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• 제14권4호
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• pp.315-324
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• 1998

TOVS에 탑재된 마이크로파 센서(MSU)와 고감도 적외복사계(HIRS)로부터 도출한 총가강수량과 SSM/I 관측으로 계산한 총가강수량으로 일본에 상륙 후, 한일해협에서 열대성 저기압으로 약화된 태풍 월트(9407)와 1995년 처음 태풍으로 발달한 태풍 페이(9503)의 운동기간 중의 수증기장 변화를 조사하는데 사용하였는데, 이들로 태풍의 운동변화에 따른 수증기장 변화를 나타낼 수 있었다. 태풍 월트와 페이의 전가강수량장은 주로 한국과 일본을 향하여 다가옴에 따라, 그들의 강도를 유지하고 강화하는데 아주 중요한 역할을 하는 북서태평양 상에 수증기의 수평수송에 주로 좌우된다. 도출된 수증기장은 두 주요구름대가 월트와 페이가 다가오고 지나가는 동안 한반도와 일본상공의 강우대 임을 나타내는 두터운 대류운 형태와 유사함을 보였다. 그러나 도출된 TOVS 전가강수량의 값은 SSM/I 값과 비교할 때 상대적으로 과소평가되었음을 나타내었다.

• 대기
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• 제31권4호
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• pp.421-431
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• 2021

The Yeongdong region is frequently vulnerable to heavy snowfall in winter in terms of societal and economical damages. By virtue of a lot of previous efforts, snowfall forecast has been significantly improved, but the performance of light snowfall forecast is still poor since it is very conducive to synoptic and mesoscale interactions, largely attributable to Taeback mountains and East Sea effects. An intensive observation has been made in cooperation with Gangwon Regional Meteorological Office and National Institute of Meteorological Studies in winter seasons since 2019. Two distinctive Cold Air Damming (CAD) events (14 February 2019 and 6 February 2020) were observed for two years when the snowfall forecast was wrong specifically in its location and timing. For two CAD events, lower-level temperature below 2 km ranged to lowest limit in comparisons to those of the previous 6-years (2014~2019) rawinsonde soundings, along with the stronger inversion strength (> 2.0℃) and thicker inversion depth (> 700 m). Further, the northwesterly was predominant within the CAD layer, whereas the weak easterly wind was exhibited above the CAD layer. For the CAD events, strong cold air accumulation along the east side of Taeback Mountains appeared to prevent snow cloud and convergence zone from penetrating into the Yeongdong region. We need to investigate the influence of CAD on snowfall in the Yeongdong region using continuous intensive observation and modeling studies altogether. In addition, the effect of synoptic and mesoscale interactions on snowfall, such as nighttime drainage wind and land breeze, should be also examined.

• 한국기후변화학회지
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• 제7권1호
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• pp.31-39
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• 2016

In this study, the time series of the number of days with $25^{\circ}C$ or higher temperatures in the Jeju region were analyzed and they showed a strong trend of increase until recently. To determine the existence of a climate regime shift in this time series, the statistical change-point analysis was applied and it was found that the number of days with $25^{\circ}C$ or higher temperatures in the Jeju region increased sharply since 1993. Therefore, in order to examine the cause of the sharp increase of the days with $25^{\circ}C$ or higher temperatures in the Jeju region, the differences between the averages of 1994~2013 and the averages of 1974~1993 were analyzed for the large-scale environment. In the Korean Peninsula including the Jeju region, precipitable water and total cloud cover decreased recently due to the intensification of strong anomalous anticyclones near the Korean Peninsula in the top, middle and bottom layers of the troposphere. As a result of this, the number of days with $25^{\circ}C$ or higher temperatures in the Jeju region could increase sharply in recent years. Furthermore, in the analysis of sensible heat net flux and daily maximum temperatures at 2 m, which is the height that can be felt by people, the Korean Peninsula was included in the positive anomaly region. In addition, the frequency of typhoons affecting the Korean Peninsula decreased recently, which reduced the opportunities for air temperature drops in the Jeju region.

• 대기
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• 제29권3호
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• pp.269-282
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• 2019

While it is important to obtain the accurate information on snowfall data due to the increase in damage caused by the heavy snowfall in the winter season, it is not easy to observe the snowfall quantitatively. Recently, snow measurements using a weighing precipitation gauge have been carried out, but there is a problem that high snowfall intensity results in low accuracy. Also, the observed snowfall data are sensitive depending on wind speed, temperature, and humidity. In this study, a new process of quality control for snow water equivalent (SWE) data of the weighing precipitation gauge were proposed to cover the low accuracy of snow data and maximize the data utilization. Snowfall data (SWE) observed by Pluvio, Parsivel, snow-depth meter using laser or ultrasonic, and rainfall gauge in Cloud Physics Observation Site (CPOS) were compared and analyzed. Applying the QC algorithm including the use of number of hydrometeor particles as reference, the increased SWE per the unit time was determined and the data noise was removed and marked by flag. The SWE data converted by the number concentration of hydrometeor particles are tested as a method to restore the QC-removed data, and show good agreement with those of the weighing precipitation gauge, though requiring more case studies. The three events data for heavy snowfall disaster in Pyeongchang area was analyzed. The SWE data with improved quality was showed a good correlation with the eye-measured data ($R^2$ > 0.73).

• Journal of Platform Technology
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• 제8권4호
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• pp.59-69
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• 2020

최근 초미세먼지 및 미세먼지에 대한 심각성은 국가적 차원의 재난으로 대두되고 있으나 지방 중소도시는 면적에 비해 미세먼지 측정소가 부족하여 미세먼지관리가 어려운 측면이 있다. 미세먼지 데이터의 수집과 처리를 위한 컴퓨팅자원은 규모가 크지않지만 데이터를 공유를 위하여 클라우드와 민간 및 공공데이터를 활용하는 것이 필요하다. 본 논문에서는 미세먼지 및 초미세먼지 그리고 온·습도를 측정하여 이를 처리하여 미세먼지 실시간 관제와 대국민서비스할 수 있는 소형 엣지컴퓨팅 시스템을 제안하였다. 미세먼지 데이터의 수집과 공공 및 민간데이터를 활용하여 미세먼지 등급을 서비스하는 것은 데이터양이 크지 않고 처리부하가 크지 않기 때문에 라즈베리파이를 이용한 엣지컴퓨팅으로 처리하는 것이 효율적이다. 실험을 위하여 3가지 센서와 라즈베리파이 그리고 Thinkspeak를 이용하여 실험시스템을 구성하였으며 경북북부권지역에 대한 미세먼지 측정을 실험하였다. 실험결과 민간의 GIS데이터 기반에 시간에 따른 측정된 미세먼지 측정결과가 정확하게 확인되었다.

• 한국정보통신학회논문지
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• 제25권6호
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• pp.766-773
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• 2021

본 논문은 숲속 야외 마루의 실시간 이용 현황을 제공할 뿐만 아니라 기계학습을 통한 예측 서비스를 제공하는 야외 마루 관리 서비스의 구현 및 성능 평가 결과를 담고있다. 개발한 하드웨어 프로토타입은 모션 감지 센서를 이용해 야외 마루의 점유 여부를 감지한 후 위치 정보, 날짜 및 시간, 온도 및 습도 데이터와 함께 클라우드 기반 데이터베이스로 전달한다. 수집된 야외 마루의 실시간 이용 현황은 이용자들에게 모바일 애플리케이션을 통해 제공된다. 성능 평가 결과 하드웨어 모듈에서부터 모바일 애플리케이션까지 평균 1.9초의 응답 시간을 보여주었으며, 정확도는 99%를 보여주고 있음을 확인하였다. 아울러 수집 데이터에다 기계학습 기반의 SVM(Support Vector Model) 모델을 적용한 야외 마루의 가용성 예측 서비스를 구현하고서 이를 모바일 및 웹 애플리케이션을 통해 제공할 수 있도록 하였다.