• Title/Summary/Keyword: Land surface temperature

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Construction of Spatial Information Big Data for Urban Thermal Environment Analysis (도시 열환경 분석을 위한 공간정보 빅데이터 구축)

  • Lee, Jun-Hoo;Yoon, Seong-Hwan
    • Journal of the Architectural Institute of Korea Planning & Design
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    • v.36 no.5
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    • pp.53-58
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    • 2020
  • The purpose of this study is to build a database of Spatial information Bigdata of cities using satellite images and spatial information, and to examine the correlations with the surface temperature. Using architectural structure and usage in building information, DEM and Slope topographical information for constructed with 300 × 300 mesh grids for Busan. The satellite image is used to prepare the Normalized Difference Built-up Index (NDBI), Normalized Difference Vegetation Index (NDVI), Bare Soil Index (BI), and Land Surface Temperature (LST). In addition, the building area in the grid was calculated and the building ratio was constructed to build the urban environment DB. In architectural structure, positive correlation was found in masonry and concrete structures. On the terrain, negative correlations were observed between DEM and slope. NDBI and BI were positively correlated, and NDVI was negatively correlated. The higher the Building ratio, the higher the surface temperature. It was found that the urban environment DB could be used as a basic data for urban environment analysis, and it was possible to quantitatively grasp the impact on the architecture and urban environment by adding local meteorological factors. This result is expected to be used as basic data for future urban environment planning and disaster prevention data construction.

Activities for the Environmental Satellite Data Center at the Science University of Tokyo

  • Takagi, Mikio
    • Proceedings of the KSRS Conference
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    • 1998.09a
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    • pp.134-137
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    • 1998
  • NOAA satellite data and GMS data have been received at the Institute of Industrial Science, University of Tokyo since early 80's and 1994, respectively. So far, all data are archived and users can look their quick look images through the Internet and get the data by request. The following processed data set will be available soon with the corporation with the Science University of Tokyo: Radiometrically corrected by 65 code and geometrically corrected NOAA data with the corporation with Iwate University and NDVI, SST and cloud classified images as their products. 1 km AVHRR Land Project Data Set of Asia and their 14 regional subsets. Geometrically corrected GMS images and surface temperature maps, sea surface temperature maps and cloud classification maps.

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Relationship between Vegetation Index and Meteorological Element in Yongdam Catchment (용담댐시험유역 기상자료와 식생지수의 상관성 분석)

  • Lee, Hyeong-keun;Hwang, Ji-hyeong;Lee, Khil-Ha
    • Journal of Environmental Science International
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    • v.27 no.11
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    • pp.983-989
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    • 2018
  • The real-time monitoring of surface vegetation is essential for the management of droughts, vegetation growth, and water resources. The availability of land cover maps based on remotely collected data makes the monitoring of surface vegetation easier. The vegetation index in an area is likely to be proportional to meteorological elements there such as air temperature and precipitation. This study investigated relationship between vegetation index based on Moderate Resolution Image Spectroradiometer (MODIS) and ground-measured meteorological elements at the Yongdam catchment station. To do this, 16-day averaged data were used. It was found that the vegetation index is well correlated to air temperature but poorly correlated to precipitation. The study provides some intuition and guidelines for the study of the droughts and ecologies in the future.

An Experimental Study on the Reduction Effects of Shading Devices on Sky Radiant Cooling in Winter (차양장치의 겨울철 천공복사 냉각 저감 효과에 관한 실험적 연구)

  • Kim, Jin-Hee;Kim, Young-Tag;Lee, Soo-Yeol;Choi, Won-Ki
    • Land and Housing Review
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    • v.12 no.1
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    • pp.129-137
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    • 2021
  • External shading devices are well known solar control devices that can help reduce the cooling load of commercial buildings. For this study, experiments were conducted to examine the feasibility of shading devices in reducing both the cooling and heating loads. The influence of sky radiant cooling during winter was verified for the external shading device, internal roller blind, and window. Results can be summarized as follows. The temperature difference between the inner and outer surfaces of the window with the external shading device was 11.8℃ compared to 14.6℃ for one without the external shading device. This 2.8℃ difference was due to heat exchange by sky radiation when the surface temperature of the shading device was lower than the ambient outdoor air temperature. The roller blind resulted in a lower temperature of 0.8℃ compared to the average temperature of the window's air cavity. This was due to heat exchange by sky radiation of the roller blind surfaces. Without shading devices, the outside surface temperature of the window is about 3℃ higher. The study also found that when external shading devices were installed on both the southwest and southeast sides, the outside surface temperature of the windows were lower on the southwest side than the southeast side.

Assimilation of Satellite-Based Soil Moisture (SMAP) in KMA GloSea6: The Results of the First Preliminary Experiment (기상청 GloSea의 위성관측 기반 토양수분(SMAP) 동화: 예비 실험 분석)

  • Ji, Hee-Sook;Hwang, Seung-On;Lee, Johan;Hyun, Yu-Kyung;Ryu, Young;Boo, Kyung-On
    • Atmosphere
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    • v.32 no.4
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    • pp.395-409
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    • 2022
  • A new soil moisture initialization scheme is applied to the Korea Meteorological Administration (KMA) Global Seasonal forecasting system version 6 (GloSea6). It is designed to ingest the microwave soil moisture retrievals from Soil Moisture Active Passive (SMAP) radiometer using the Local Ensemble Transform Kalman Filter (LETKF). In this technical note, we describe the procedure of the newly-adopted initialization scheme, the change of soil moisture states by assimilation, and the forecast skill differences for the surface temperature and precipitation by GloSea6 simulation from two preliminary experiments. Based on a 4-year analysis experiment, the soil moisture from the land-surface model of current operational GloSea6 is found to be drier generally comparing to SMAP observation. LETKF data assimilation shows a tendency toward being wet globally, especially in arid area such as deserts and Tibetan Plateau. Also, it increases soil moisture analysis increments in most soil levels of wetness in land than current operation. The other experiment of GloSea6 forecast with application of the new initialization system for the heat wave case in 2020 summer shows that the memory of soil moisture anomalies obtained by the new initialization system is persistent throughout the entire forecast period of three months. However, averaged forecast improvements are not substantial and mixed over Eurasia during the period of forecast: forecast skill for the precipitation improved slightly but for the surface air temperature rather degraded. Our preliminary results suggest that additional elaborate developments in the soil moisture initialization are still required to improve overall forecast skills.

Atmospheric Characteristics of Fog Incidents at the Nakdong River : Case Study in Gangjeong-Goryeong Weir (낙동강 유역 안개 발생시 기상 특성: 강정고령보 사례를 중심으로)

  • Park, Jun Sang;Lim, Yun-Kyu;Kim, Kyu Rang;Cho, Changbum;Jang, Jun Yeong;Kang, Misun;Kim, Baek-Jo
    • Journal of Environmental Science International
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    • v.24 no.5
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    • pp.657-670
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    • 2015
  • Visibility and Automatic Weather System(AWS) data near Nakdong river were analyzed to characterize fog formation during 2012-2013. The temperature was lower than its nearby city - Daegu, whereas the humidity was higher than the city. 157 fog events were observed in total during the 2 year period. About 65% of the events occurred in fall (September, October, and November) followed by winter, summer, and spring. 94 early morning fog events of longer than 30 minutes occurred when south westerly wind speed was lower than 2 m/s. During these events, the water temperature was highest followed by soil surface and air temperatures due to the advection of cold and humid air from nearby hill. The observed fog events were categorized using a fog-type classification algorithm, which used surface cooling, wind speed threshold, rate of change of air temperature and dew point temperature. As a result, frontal fog observed 6 times, radiation 4, advection 13, and evaporation 66. The evaporation fog in the study area lasted longer than other reports. It is due to the interactions of cold air drainage flow and warm surface in addition to the evaporation from the water surface. In particular, more than 60% of the evaporation fog events were accompanied with cold air flows over the wet and warm surface. Therefore, it is needed for the identification of the inland fog mechanism to evaluate the impacts of nearby topography and land cover as well as water body.

Distribution of Relative Evapotranspiration Availability using Satellite Data in Daegu Metropolitan (위성 자료를 이용한 대구광역시의 상대적 증발산 효율 분포)

  • Kim, Hae-Dong;Im, Jin-Wook;Lee, Soon-Hwan
    • Journal of the Korean earth science society
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    • v.27 no.6
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    • pp.677-686
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    • 2006
  • Surface evapotranspiration is one of the most important factors to determine the surface energy budget, and its estimation is strongly related with the accuracy of weather forecasting. Surface evapotranspiration over Daegu Metropolitan was estimated using high resolution LANDSAT TM data. The estimation of surface evapotranspiration is based on the relationship between surface radiative temperature and vegetation index provided by a TM sensor. The distribution of NDVI (Normalized Difference of Vegetation Index) corresponds well with that of land-used in Deagu Metropolitan. The temperature of several part of downtown in Deagu metropolitan is lower in comparison with the averaged radiative temperature. This is caused by the high evapotranspiration from dense vegetation like DooRyu Park in Deagu Metropolitan. But, weak evapotranspiration availability is distinguished over the central part of downtown and the difference of evapotranspiration availability on industrial complexes and residential area is also clear.

General Oceanographic Factors In Yeongil Bay Of Korea, Late October 1973 (가을철 영일만수괴의 일반해양학적 특성)

  • Kwak, Hi-Sang
    • 한국해양학회지
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    • v.11 no.2
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    • pp.89-95
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    • 1976
  • Some factors of seawater such as water temperature, salinity, pH, dissolved oxygen and asturation of dissolved oxygen were determined in 5 meters intervals from surface to bottom at 11 stations in Yeongil Bay of Korea during late October 1973. Distribution pattern of water masses in Yeongil Bay during the period seemed to be heterogeneous as dividing into two parts of surface and bottom. Water temperature, pH, dissolved oxygen and saturation of dissolved oxygen of surface water mass showed higher values and salinity of the mass showed lower values than those factors of bottom water mass. Surface water mass might be originated from Tsushima current during summer season and bottom water mass from cold body of East Sea of Korea which seemed to extend to coastal zone during winter season. Land water discharge from Hyeongsan River into the Bay is considered as a minor factor playing slight role in the water mass composition of the area.

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Numerical Simulation of Local Circulation Over the Daechung Lake Area by Using the Mesoscale Model (중규모 수치 모델을 이용한 대청 호수 주변의 국지 순환 모의)

  • Byon, Jae-Young;Choi, Young-Jean;Seo, Beom-Keun
    • Journal of the Korean earth science society
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    • v.30 no.4
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    • pp.464-477
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    • 2009
  • In this study, we examined the patterns of local circulation over the Daechung lake area through the numerical experiment designed to investigate the impact of lake on the local circulation. The results of numerical experiment showed that the surface temperature predicted by WRF model was lower than the observation, while the wind speed was stronger than the observation. The local circulation over the lake area was characterized by a lake breeze induced by a horizontal thermal contrast between the lake surface and the Surrounding land. At Daecheong Lake, a lake breeze formed at 09 LST and dissipated at 18 LST, with maximum intensity at 15 LST. The vertical extent of the simulated circulation was about 1,200 m. The specific humidity increased as the humid air above the lake moved landward due to the daytime circulation of the lake breeze. The numerical experiments of sensitivity to existence of the lake showed that the simulated surface temperature decreased in the experiment with the lake. Wind speed was more intense around the lake area when the actual land use was substituted by grassland land use. The results of numerical experiments suggest that the lake-induced lake breeze circulation has an effect on the meteorology of planetary boundary layer around the lake.

Accuracy evaluation of near-surface air temperature from ERA-Interim reanalysis and satellite-based data according to elevation

  • Ryu, Jae-Hyun;Han, Kyung-Soo;Park, Eun-Bin
    • Korean Journal of Remote Sensing
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    • v.29 no.6
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    • pp.595-600
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    • 2013
  • In order to spatially interpolate the near-surface temperature (Ta) values, satellite and reanalysis methods were used from previous studies. Accuracy of reanalysis Ta was generally better than that of satellite-based Ta, but spatial resolution of reanalysis Ta was large to use at local scale studies. Our purpose is to evaluate accuracy of reanalysis Ta and satellite-based Ta according to elevation from April 2011 to March 2012 in Northeast Asia that includes various topographic features. In this study, we used reanalysis data that is ERA-Interim produced by European Centre for Medium-Range Weather Forecasts (ECMWF), and estimated satellite-based Ta using Digital Elevation Meter (DEM), Normalized Difference Vegetation Index (NDVI), difference between brightness temperature of $11{\mu}m$ and $12{\mu}m$, and Land Surface Temperature (LST) data. The DEM data was used as auxiliary data, and observed Ta at 470 meteorological stations was used in order to evaluate accuracy. We confirmed that the accuracy of satellite-based Ta was less accurate than that of ERA-Interim Ta for total data. Results of analyzing according to elevation that was divided nine cases, ERA-Interim Ta showed higher accurate than satellite-based Ta at the low elevation (less than 500 m). However, satellite-based Ta was more accurate than ERA-Interim Ta at the higher elevation from 500 to 3500 m. Also, the width of the upper and lower quartile appeared largely from 2500 to 3500 m. It is clear from these results that ERA-Interim Ta do not consider elevation because of large spatial resolution. Therefore, satellite-based Ta was more effective than ERA-Interim Ta in the regions that is range from 500 m to 3500 m, and satellite-based Ta was recommended at a region of above 2500 m.