• 대한원격탐사학회지
• /
• 제39권1호
• /
• pp.99-110
• /
• 2023

Land surface temperature (LST) is a critical environmental indicator affected by land cover (LC) changes. Currently, the most convenient and fastest way to retrieve LST is to use remote sensing images due to their continuous monitoring of the Earth's surface. The work intended to investigate land cover change and temperature response inAn-Najaf province. Landsat multispectral imageries acquired inAugust 1989, 2004, and 2021 were employed to estimate land cover change and LST responses. The findings exhibited an increase in water bodies, built-up areas, plantations, and croplands by 7.78%, 7.27%, 6.98%, 3.24%, and 7.78%, respectively, while bare soil decreased by 25.27% for the period (1989-2021). This indicates a transition from barren lands to different land cover types. The contribution index (CI) was employed to depict how changes in land cover categories altered mean region surface temperatures. The highest LSTs recorded were in bare lands (42.2℃, 44.25℃, and 46.9℃), followed by built-up zones (41.6℃, 43.96℃, and 44.89℃), cropland (30.9℃, 32.96℃, and 34.76℃), plantations (35.4℃, 36.97℃, and 38.92℃), and water bodies (27.3℃, 29.35℃, and 29.68℃) respectively, in 1989, 2004, and 2021. Consequently, these changes resulted in significant variances in LST between different LC types.

• 대한원격탐사학회지
• /
• 제32권6호
• /
• pp.603-616
• /
• 2016

본 연구에서는 기상청 현업 국지기상모델(Local Data Assimilation and Prediction System, LDAPS)과 전산유체역학(Computational Fluid Dynamics, CFD) 모델을 접합하여, 서울 종로구 송월동에 위치한 지동기상관측소(서울 ASOS) 주변 지역의 기상 환경을 분석하였다. 토지 피복별 차등 가열이 도시 지역의 대기 흐름과 기온에 미치는 영향을 분석하기 위하여, 시간 변화에 따른 토지 피복별 지표면 온도와 그림자 영역에 대한 지표면 온도 감소 효과를 고려하였다. LDAPS 모델은 상세한 건물, 지형, 지표면 가열 효과를 고려하지 못하기 때문에, 풍속을 과대모의 하고 기온을 과소 모의하였다. 건물과 지형의 마찰 효과와 태양 복사에 의한 지표면 가열을 고려할 수 있는 LDAPS-CFD 접합 모델은 서울 ASOS 지점의 관측 풍속과 유사한 풍속을 모의하였고, 관측 기온을 잘 재현하였다. 주로 동풍이 부는 오전 시간대에는 LDAPS-CFD 접합 모델 또한 기온을 과소모의 하였는데, 이는 서울 ASOS 지점의 풍상측(동쪽)에 위치한 경희궁 주변 지역에 주로 수목이 분포하고 있고, 표면 온도가 상대적으로 낮기 때문인 것으로 판단된다. 그러나, 주로 남동풍 계열의 바람이 부는 오후 시간대에는 풍상측에 위치한 건물의 표면 가열의 효과로 인해 서울 ASOS 지점의 관측 기온을 상대적으로 잘 모의하였다.

• 토지주택연구
• /
• 제2권4호
• /
• pp.463-469
• /
• 2011

LH has installed sashes to the balcony to save energy and increase residential space. Then, it is very difficult to protect a condensation of vapor on the walls in the winter time, because the space is closed and the wall surface temperature becomes very low in a balcony. We have tried to get the optimal thermal design methods to reduce the condensation on the walls. The one of the chosen method is to make holes on the walls, and then the condensation shall be reduce because the dew point temperature will be lower due to the effect of dehumidify. In this case, it is just necessary to find as like that how many holes should be perforated through the wall, what's their size, and where is their positions. In this study, a computational fluid dynamics was applied to analyze the temperature, the pressure and the velocity distribution for an incompressible flow in the balcony spaces. And field tests were also carried out to get the data to compare to the simulation results. Finally the design criteria of the ventilation holes in the balconies was suggested by analysis of the computer simulation models.

• 대기
• /
• 제23권1호
• /
• pp.13-21
• /
• 2013

In this study, the effects of atmospheric stability and surface temperature on the microscale local airflow are investigated in a hydrological suburban area using a computational fluid dynamics (CFD) model. The model domain includes the river and industrial complex for analyzing the effect of water system and topography on local airflow. The surface boundary condition is constructed using a geographic information system (GIS) data in order to more accurately build topography and buildings. In the control experiment, it is shown that the topography and buildings mainly determine the microscale airflow (wind speed and wind direction). The sensitivity experiments of atmospheric stability (neutral, stable, and unstable conditions) represent the slight changes in wind speed with the increase in vertical temperature gradient. The differential heating of ground and water surfaces influences on the local meteorological factors such as air temperature, heat flow, and airflow. These results consequentially suggest that the meteorological impact assessment is accompanied by the changes of background land and atmospheric conditions. It is also demonstrated that the numerical experiments with very high spatial resolution can be useful for understanding microscale local meteorology.

• 한국환경복원기술학회지
• /
• 제6권3호
• /
• pp.79-85
• /
• 2003

Human beings have pursued development and economic betterment; thus, enhancing convenience and prosperity. A flourish of human civilization upon the industrialization results a massive urbanization. However, human beings have connived the environmental importance in the course of rapid urbanization. The environmental quality now becomes one of the most important factors that determine the quality of life in a city. Many studies were proceeded about the heat island effect in large cities. In general, most studies have been done to investigate urban microclimate phenomena using meteorological network or AWS (automatic weather station) data. Those preceding studies do not seem to sufficiently reflect the and thus, failed to show regional representative. In this study, temporal Landsat TM satellite imageries of May 20, 1987 and May 21, 1999 were 뻐d in order to detect the surface temperature of the study area using the band 6 ($10.4{\mu}m{\sim}12.5{\mu}m$). The surface temperature distribution detected by the band 6 of Landsat TM was over layed with the land cover classification data in order to investigate the temperature difference of the paved road and the riparian areas of the stream. As a result, a surface temperature difference as much as $3^{\circ}C$ between the paved road and the riparian areas with vegetation was observed. This study concludes that the land cover change is one of the main causes of urban heat island effect which may be closely affected by the paved areas and roads. Besides, the change of the atmospheric temperature followed by the urban secular change could have been confirmed. In the case of Yangjaecheon stream which underwent a heavy environmental restoration in 1995, the temperature was decreased as much as $0.6^{\circ}C$ after the restoration. The results of this study is expected to contribute to develop an urban space in harmony with the healthy human life and the environment respecting the crucial role of vegetation to stabilize the urban environmental dynamics.

• Journal of Ecology and Environment
• /
• 제30권3호
• /
• pp.209-223
• /
• 2007

Twenty-four wetlands located in Higashi-Hiroshima City in West Japan were selected for this study in order to investigate both the relationship between aquatic plant composition and environmental conditions; and the relationship between changing land use patterns in the catchments and the concentration of different forms of nitrogen in the wetlands. The dominant and subdominant species which comprised the principal vegetation were determined based on a vegetation census conducted in each wetland during the growing season from June to August, 2006. The seasonal variations of water quality factors (pH, electrical conductivity, turbidity, dissolved oxygen, total dissolved solid, and temperature) and different forms of nitrogen such as nitrite, nitrate, ammonium, total nitrogen, dissolved organic nitrogen and dissolved inorganic nitrogen concentrations were analyzed as important indicators of water quality for the surface water of the wetlands. The surveyed wetlands were classified into three types (non-disturbed wetlands, moderately-disturbed wetlands and highly-disturbed wetlands), based on the degree of human disturbance to their catchment areas. An analysis of variance indicated that there was a significant difference among the wetland groups in the annual mean values of electrical conductivity, total dissolved solids, total nitrogen, nitrite, dissolved inorganic nitrogen and dissolved organic nitrogen. Classification of the wetlands into three groups has revealed a pattern of changes in the composition of plant species in the wetlands and a pattern of changes in nitrogen concentrations. A majority of the non-disturbed wetlands were characterized by Brasenia schrebi and Trapa bispinosa as dominant; with Potamogeton fryeri and Iris pesudacorus as sub-dominant species. For most of the moderately-disturbed wetlands, Brasenia schrebi were shown to be a dominant species; Elocheriss kuriguwai and Phragmites australis were observed as sub-dominant species. For a majority of the highly-disturbed wetlands, Typha latifolia and T. angustifolia were observed as dominant species, and Nymphea tetragona as the sub-dominant species in the study area. An analysis of land use and water quality factors indicated that forest area played a considerable role in reducing the concentration of nutrients, and can act as a sink for surface/subsurface nutrient inputs flowing into wetland water, anchor the soil, and lower erosion rates into wetlands.

• ALGAE
• /
• 제24권3호
• /
• pp.149-161
• /
• 2009

Characteristics of benthic microalgae and sediment properties were investigated for the intertidal flats of Kwangyang Bay, Korea. Sampling stations were selected every 100 m in the intertidal flats from land-side to open ocean at two different sampling sites. Samples were collected in June 2004, July, September, November, February and May 2005. Sediments properties were measured including temperature, water contents, sediment bulk density, nutrient concentrations in porewater. Chlorophyll a concentrations in surface sediment (0.5 cm) were measured and relationships between the chlorophyll a and various sediment properties were analyzed to identify major mechanisms regulating biomass of benthic microalgae in the intertidal flats using simple linear regression analysis. Sediment chlorophyll a concentrations were maximum during winter and minimum during warm seasons ranging from 4.4 mg $m^{-2}\;to\;81.2\;mg\;m^{-2}$. No clear spatial variations were observed for the sediment chlorophyll a in the study sites. Results from regression analysis suggested that benthic microalgae biomass was affected by sediment temperature and nutrients especially ammonium and silicate. Grazing effect was estimated using chlorophyll: pheopigments ratio, indirect indicator of grazing activity, and the positive correlation of the ratio and chlorophyll a implied that microalgae biomass is affected by grazing of zoobenthos although direct measurement of grazing activity is required to determine the importance of top-down controls in the benthic microalgae dynamics.

• 환경영향평가
• /
• 제24권2호
• /
• pp.134-153
• /
• 2015

도시 계획적 측면에서 도시의 구조적 변화에 따른 기후영향을 파악하여 그 결과를 도시계획에 반영하는 것은 중요하다. 서울시에서는 도시계획 시나리오 정보를 제공하기 위해 도시계획정보시스템(Urban Plan Information System, UPIS)을 활용 중이다. 지자체의 실제 도시계획에 따른 기후영향을 평가하고 분석하기 위해서는 UPIS에서 제공하는 도시계획시나리오와 도시기후분석모델을 손쉽게 연계할 수 있어야 한다. 본 연구에서는 국립기상과학원의 도시기후분석모델(Climate Analysis Seoul, CAS)과 도시계획 시나리오를 연계하는 기술을 개발하였다. CAS는 건물과 식생의 물리적 배치에 따른 온도, 바람 등의 국지규모 변화와 중규모 기상모델인 MetPhoMod(METeorology and atmospheric PHOtochemistry mesoscale MODel)의 분석결과를 바탕으로 찬공기의 생성, 이동, 정체와 바람흐름, 열적환경 등을 분석하는 기능을 가지고 있다. 정밀한 도시정보를 모델에 적용하기 위해 고해상도의 항공 LiDAR(LIgit Detection And Ranging) 측량을 통해 생성된 래스터자료(1m 해상도)와 KOMPSAT-2(KOrea Multi-Purpose SATellite) 위성영상 자료(4m 해상도)를 이용하여 토지피복 및 수치표고자료로 활용할 입력자료를 생성하였다. 보다 정확한 도시지면 특징을 반영하기 위해 수치표면모델인 DSM(Digital Surface Model)과 수치지형모델인 DTM(Digital Terrain Model)을 전산유체역학모델(Computational Fluid Dynamics, CFD) 입력자료로 사용하여 상세바람분석을 수행하였다. 8방위의 유입류를 고려하여 재정비 전후의 도시구조물 주변의 흐름 및 풍속 분포와 녹지축 형성 전후의 열환경 변화를 분석하였다. 현실적인 기상상태 반영을 위해 CAS의 중규모 기상장을 입력자료로 사용하였으며, 그 결과 재정비에 따른 도시구조물 변화에 의해 바람길에 큰 변화가 확인되었다. 녹지축 형성 이후 전반적으로 재정비지역 주변의 온도가 감소하였다. CAS와 CFD의 연동을 통해 도시지역 재정비와 녹지축 형성 전후의 주변 바람길과 열환경에 대한 실제적인 평가가 가능하며, 도시개발계획과 녹지조성계획 수립에 유용할 것으로 기대된다.