• 한국소프트웨어감정평가학회 논문지
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• 제15권2호
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• pp.59-66
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• 2019

제주는 농업과 관광이 절대적 비중이므로 강수에 대한 예측/분석은 다른 지역보다 더 중요한 요소로 작용한다. 현재 제주도의 강수 예측은 기상위성을 통해 얻어지는 관측데이터에 수치모델을 이용하나, 다른 지역보다 강수 현상에 대한 변화가 다양하므로 기존의 일반적인 수치모델을 그대로 적용하여 강수 예측/분석을 하기는 쉽지 않고 만족할만한 결과를 얻기가 어렵다. 따라서 제주지역에 맞는 새로운 제주 예측/분석 방법이 연구돼야 할 것이다. 본 논문에서는 합성곱신경망 (Convolution Neural Network, CNN) 기반의 텍스처(Texture) 분석기법을 이용한 제주 강수패턴 분석 방법을 제안한다. 제안하는 방법은 기상위성에서 획득한 제주도 영역에 대한 수증기영상과 지역의 온도정보를 텍스처 영상으로 변환한 후, 변환된 영상들을 합성곱신경망을 이용하여 강수 여부를 분석하는 방법이다. 제안한 방법을 구현하고 실험을 통하여 제안된 방법의 유효성을 보인다.

• 천문학회지
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• 제56권1호
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• pp.75-89
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• 2023

We investigate the astronomical phenomenon records of Sukjong's Chunbang-Ilgi made by Sigangwon (Royal Educational Office of the Crown Prince) at which King Sukjong was the crown prince (i.e., 1667 January 24-1674 September 22). From the daily records of 2,799 days, we extract the astronomical records of 1,443 days and classify them into 14 categories. Then, we group the records of each category into five phenomena (Atmosphere, Eclipse, Daylight Appearance, Apparition, and Appulse) and compare them with the results of modern astronomical computations wherever possible. Except for Atmosphere group comprising records of meteorological events, such as solar halo, lunar halo, and unusual clouds, the significant findings in every other group are as follows: In Eclipse group, the solar eclipse that occurred on 1673 August 12 was unobservable in Korea, which is in contrast to the record of Joseonwangjo-Sillok (Annals of the Joseon Dynasty), which states that the sun was in eclipse around sunset time, as observed at Nam mountain. From the lunar eclipse records, we verify that the Joseon court did not change the date of the events observed after midnight. In Daylight Appearance group, we confirm that this phenomenon was observed during the daytime and not during twilight. We further suggest that if observation conditions are met, a celestial body brighter than -2.3 mag could be seen during the daytime with the naked-eye. In Apparition group, we find the possibilities that the Orionid meteor shower had influence on the meteor records and the seasonality on the aurora records. We also find that the Korean records in which the coma of comet C/1668 E1 was located below the horizon were overlooked in previous studies. Finally, we find that the records of Appulse group generally agree with the results of modern calculations. The records of Beom (trespass in literal) and Sik (eating in literal) events show average angular separations of 1.2° and 1.0°, respectively. In conclusion, we believe this work helps study the astronomical records of other logs of Sigangwon, such as Sukjong's Chunbang-Ilgi.

• 한국농공학회논문집
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• 제66권3호
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• pp.25-37
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• 2024

Global warming-induced drought inflicts significant socio-economic and environmental damage. In Korea, the persistent drought in the southern region since 2022 has severely affected water supplies, agriculture, forests, and ecosystems due to uneven precipitation distribution. To effectively prepare for and mitigate such impacts, it is imperative to develop proactive measures supported by early monitoring systems. In this study, we analyzed the spatiotemporal changes of multiple evapotranspiration-based drought indices, focusing on the flash drought event in the southern region in 2022. The indices included the Evaporative Demand Drought Index (EDDI), Standardized Precipitation Evapotranspiration Index (SPEI) considering precipitation and temperature, and the Evaporative Stress Index (ESI) based on satellite images. The Standardized Precipitation Index (SPI) and SPEI indices utilized temperature and precipitation data from meteorological observation stations, while the ESI index was based on satellite image data provided by the MODIS sensor on the Terra satellite. Additionally, we utilized the Evaporative Demand Drought Index (EDDI) provided by the North Oceanic and Atmospheric Administration (NOAA) as a supplementary index to ESI, enabling us to perform more effective drought monitoring. We compared the degree and extent of drought in the southern region through four drought indices, and analyzed the causes and effects of drought from various perspectives. Findings indicate that the ESI is more sensitive in detecting the timing and scope of drought, aligning closely with observed drought trends.

• 한국환경과학회지
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• 제33권1호
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• pp.75-85
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• 2024

An intensive observing period (IOP) of heatwaves in the urban region of Seoul in the summer of 2023 was carried out to understand the changes in air temperature and road temperature induced by environmental conditions. The temperature observed at eight points with different urban environmental conditions was compared with the temperature by the KMA/AWS to analyze the characteristics of change in air temperature by height and the change in road temperature according to environmental conditions and road sprinkler. The comparison of the average temperature observed in different urban environmental conditions with the temperature observed at KMA/AWS showed that the air temperature in asphalt and open space sites was 0.7 to 2.3℃ higher and that the one in bus stops was 0.9 to 2.3℃ higher. In terms of temperature deviations depending on residential type, the temperature in highly populated areas was about 0.1 to 0.8℃ higher than that of apartment complexes. In addition, regardless of the size of a park, the temperature in the park was lower than the temperature in dense housing areas and apartment complexes. In asphalt and residential areas, the road temperature was higher than the temperature at a height of 150 cm, Conversely, road temperature was lower than air temperature in a shaded shelter and large park. In addition, after spraying a surface road, the road temperature immediately dropped by about 3 to 4℃; however, after about 20 minutes, it rose again to the previous road temperature. This change in road temperature appeared only for the temperature of 30 cm height.

• 대기
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• 제34권2호
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• pp.187-202
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• 2024

We analyzed the observed characteristics of monoterpene and developed an empirical formula for monoterpene concentration in the pine-dominated mixed forest of the National Center for Forest Therapy. Monoterpene was measured at 0800, 1200 and 1700 LST once a month using sorbent tube sampling coupled with thermal desorption gas chromatography and mass spectrometry. Monoterpene concentration is low in winter and shows a maximum in June and July. The major components of monoterpene are alpha-pinene, camphene and beta-pinene. During the warm period from May to November, monoterpene concentration is higher at 0800 and 1700 LST than at 1200 LST. The empirical formula takes into account the vegetation variables, temperature-controlled emission, oxidation processes and dilution by wind. The vegetation variable accounts for the difference in observed monoterpene concentration between two sites. The observed monoterpene concentration normalized by the vegetation variable increases exponentially with air temperature. The oxidation process explains the lower monoterpene concentration at 1200 LST than at 0800 and 1700 LST during the warm period. The monoterpene estimates using the empirical formula shows a correlation of 0.52 with the observation for the development period (2018~2020), while it shows a correlation of 0.72 for the validation year (2021). Such higher correlation for the validation year than for the development period is due to the fact that variability of monoterpene concentration is better explained by air temperature in 2021 than in the development period. However, the developed formula underestimates the monoterpene concentration in May and June, showing the limitation in accurately capturing the monthly variation of monoterpene.

• 지질공학
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• 제34권2호
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• pp.329-338
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• 2024

본 연구에서는 인제 지역에 대해 표준강수지수(SPI), 수문학적 가뭄지수(SDI)를 이용한 가뭄 평가를 수행하였다. 가뭄 분석을 위한 기초자료(강우, 유량) 자료 등을 통해서 월별 유량 비율 등을 검토하였고, 인제군 유역 인근의 강수 및 수위/유량 관측소를 활용하여 기상학적 가뭄 및 수문학적 가뭄분석을 진행한 결과 모든 가뭄지수(SPI, SDI)에서 공통적으로 2014년에 발생한 가뭄이 2017년까지 지속되었던 것으로 분석되었다. 지속기간 12개월의 수문기상자료를 활용하여 가뭄지수를 산정하여 분석한 경우, 심한가뭄 지속기간이 24개월 정도 지속되었던 것으로 확인되었으며 따라서 가뭄으로 인한 피해가 극심했을 것으로 평가된다.

• Journal of Ecology and Environment
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• 제47권4호
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• pp.264-271
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• 2023

Environmental crises caused by climate change and human-induced disturbances have become urgent challenges to the sustainability of human beings. These issues can be addressed based on a data-driven understanding and forecasting of ecosystem responses to environmental changes. In this study, we introduce a long-term ecological monitoring system in Korean Long-Term Ecological Research (KLTER), and a plan for the Korean Ecological Observatory Network (KEON). KLTER has been conducted since 2004 and has yielded valuable scientific results. However, the KLTER approach has limitations in data integration and coordinated observations. To overcome these limitations, we developed a KEON plan focused on multidisciplinary monitoring of the physiochemical, meteorological, and biological components of ecosystems to deepen process-based understanding of ecosystem functions and detect changes. KEON aims to answer nationwide and long-term ecological questions by using a standardized monitoring approach. We are preparing three types of observatories: two supersites depending on the climate-vegetation zones, three local sites depending on the ecosystem types, and two mobile deployment platforms to act on urgent ecological issues. The main observation topics were species diversity, population dynamics, biogeochemistry (carbon, methane, and water cycles), phenology, and remote sensing. We believe that KEON can address environmental challenges and play an important role in ecological observations through partnerships with international observatories.

• 한국지구과학회지
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• 제45권4호
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• pp.349-362
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• 2024

We aimed to evaluate the effectiveness of ensemble optimal interpolation (EnOI) in improving the analysis of significant wave height (SWH) within wave models using satellite-derived SWH data. Satellite observations revealed higher SWH in mid-latitude regions (30° to 60° in both hemispheres) due to stronger winds, whereas equatorial and coastal areas exhibited lower wave heights, attributed to calmer winds and land interactions. Root mean square error (RMSE) analysis of the control experiment without data assimilation revealed significant discrepancies in high-latitude areas, underscoring the need for enhanced analysis techniques. Data assimilation experiments demonstrated substantial RMSE reductions, particularly in high-latitude regions, underscoring the effectiveness of the technique in enhancing the quality of analysis fields. Sensitivity experiments with varying ensemble sizes showed modest global improvements in analysis fields with larger ensembles. Sensitivity experiments based on different decorrelation length scales demonstrated significant RMSE improvements at larger scales, particularly in the Southern Ocean and Northwest Pacific. However, some areas exhibited slight RMSE increases, suggesting the need for region-specific tuning of assimilation parameters. Reducing the observation error covariance improved analysis quality in certain regions, including the equator, but generally degraded it in others. Rescaling background error covariance (BEC) resulted in overall improvements in analysis fields, though sensitivity to regional variability persisted. These findings underscore the importance of data assimilation, parameter tuning, and BEC rescaling in enhancing the quality and reliability of wave analysis fields, emphasizing the necessity of region-specific adjustments to optimize assimilation performance. These insights are valuable for understanding ocean dynamics, improving navigation, and supporting coastal management practices.

• 한국지리정보학회지
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• 제23권3호
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• pp.100-119
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• 2020

최근 온도상승으로 인한 폭염 증가와 대기 풍속의 약화가 상호작용하면서 열환경과 미세먼지(PM₁₀)가 문제가 되고 있다. 도시지역 내에서 다른 지역들보다 온도와 대기오염 농도가 높은 도시열섬과 도시오염섬 현상이 나타나고 있음이 알려져 있으나, 공간데이터로 구축 가능한 미세 자료의 부족 등으로 이를 함께 살펴본 연구는 많지 않았다. 최근 위성영상과 민간통신업체의 인프라에서 측정한 빅데이터들이 생산되면서 온도와 대기오염에 대한 세밀한 공간분포 분석이 가능하게 되었다. 이에 본 연구는 부산광역시를 대상으로 도시열섬과 도시오염섬의 공간적 분포패턴을 살펴보고 두 현상의 분포 특성을 비교 분석하고자 하였다. 연구에는 Landsat 8 위성영상의 지표면온도와 민간자동관측시스템에서 도출된 대기온도, 미세먼지농도 데이터를 30m*30m 단위로 격자화하여 공간분석을 수행하였다. 분석 결과, 도시열섬과 도시오염섬이 동시에 발생하는 대표적인 지역들로 취약 주거지역과 공업지역들이 다수 포함되어 있었다. 부산시의 대표적 주거 취약지역으로 알려진 서동, 반송동 등의 주요 정책이주지가 포함되었는데 해당 지역은 소규모 필지에 건축물의 밀도가 상당히 높은 지역으로 통풍, 환기 등에 문제가 많은 주거지역이다. 이러한 지역의 주민 중 상당수는 폭염과 대기오염에 대한 대응 능력이 낮아 관련 정책 수립 시 우선적으로 이 지역들이 고려될 필요가 있다. 도시열섬과 도시오염섬의 동시발생지역에 포함된 공업지역들은 콘크리트나아스콘 기반의 불투수면의 비중이 높고, 식생이 부족할 뿐 아니라 교통량도 많은 것으로 나타났다. 도시열섬과 도시오염섬 분석에 대한 신뢰성을 살펴보기 위해 핫스팟분석을 진행한 결과, 99.96% 이상의 지역이 99% 신뢰수준의 핫스팟지역에 해당함을 확인할 수 있었다.

• 대한원격탐사학회지
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• 제38권6_2호
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• pp.1691-1707
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• 2022

한반도와 중국 경계에 위치한 백두산의 칼데라호인 천지호는 계절에 따라 해빙과 결빙을 반복한다. 천지 아래에는 마그마 챔버가 존재하며 마그마 챔버의 변화에 의해 온천수의 온도 및 수압 변화와 같은 화산 전조현상이 발생한다. 이에 따라, 천지호 내에서 다른 부분보다 해빙이 빠르며 결빙기에도 늦게 얼며 물표면 온도가 높은 이상지역이 존재하게 된다. 해당 이상지역은 온천수 방출 지역으로, 이상지역의 얼음변화도 값을 통해 화산활동을 모니터링 할 수 있다. 그러나 지리적, 정치적 그리고 공간적 문제로 천지의 이상지역을 주기적으로 관측하기에는 한계가 존재한다. 따라서 본 연구에서는 Landsat -5/-7/-8 광학위성영상으로부터 Modified U-Net 회귀모델을 이용하여 이상지역내의 얼음변화도를 정량적으로 관측하였다. 1985년 1월 22일부터 2020년 12월 8일까지 이상지역을 갖는 83장의 Landsat 영상의 Visible and Near Infrared (VNIR)대역을 활용하였다. 얼음 변화도를 정량적으로 관측을 위해 VNIR대역에서 수체와 얼음과의 상대적인 분광반사도를 활용하여 새로운 데이터를 만들었다. 가시광선대역과 근적외선 대역이 가지고 있는 정보를 최대한 유지하기 위해 2개의 인코더를 가진 U-Net에 적용하여 얼음변화도를 관측하였으며 Root Mean Square Error (RMSE) 140, 상관계수 0.9968의 높은 예측 성능을 보여주었다. 따라서 Modified U-Net을 활용하면 추후 Landsat 영상으로부터 얼음변화도 값을 높은 정확도로 관측하므로 백두산 화산활동을 모니터링하는 방법 중 하나로 사용될 수 있으며, 다른 화산 모니터링 기법과 더불어 활용한다면 더욱 정밀한 화산감시체계 구축이 가능할 것이다.