Improvement of Air Temperature Analysis by Precise Spatial Data on a Local-scale - A Case Study of Eunpyeong New Town in Seoul -

Yi, Chaeyeon; An, Seung-Man; Kim, Kyu-Rang; Choi, Young-Jean; Scherer, Dieter

doi:10.11108/kagis.2012.15.1.144

Cited by 15 publications

(5 citation statements)

References 2 publications

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“…The total air temperature deviation (TD) is the sum of the meso‐scale air temperature deviation (MD) and the local‐scale air temperature deviation (LD) by assumption. MD, LD, and TD are computed by the CAS workflow as spatially changing variables to represent spatial temperature deviation rather than being meteorological variables (Yi et al , ).…”

Section: Methodsmentioning

confidence: 99%

Estimating spatial patterns of air temperature at building‐resolving spatial resolution in Seoul, Korea

Yi¹,

Kim

et al. 2015

Intl Journal of Climatology

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ABSTRACT:The thermal environment in urban areas is substantially influenced by local surface properties and their modification through human activities. The effects of urban climate on human health are one of the motivations for the development of various urban climate analysis tools. Climate Analysis Seoul (CAS) is a tool that incorporates a meso-scale atmospheric model and conceptual geographic information system (GIS)-based models to provide gridded air temperature deviations based on high-resolution land cover information. The CAS output was evaluated using air temperatures observed at 18 automatic weather stations (AWS) located in the detail region (DR) Eunpyeong. Correlation analyses were performed to reveal the influence of different land cover characteristics and CAS output variables on measured air temperature deviations. Based on the results of the correlation analyses in the study region (SR) Seoul, a regression model (total air temperature distribution, TD ′ ) was developed. It predicts spatially distributed air temperatures based on morphological parameters and an observed reference temperature. Using the TD ′ model, maps of daily maximum air temperatures were produced for the entire area of Seoul with a horizontal resolution of 25 m, and of 5 m for the DR, the latter allows to assess the impacts of different building and vegetation structures on air temperature by resolving buildings. The TD ′ model was evaluated using measurements at eight AWS. The TD ′ model slightly overestimated daily maximum air temperatures in 2007 and 2011, but performed better for 2011, mainly because land cover data represent the final state of the urban development. The TD ′ model appears to be a suitable tool for estimating air temperature distributions at building-resolving resolutions. It can be used to assess changes in the thermal environment and heat-related hazards through urban development plans already ahead of their realization.KEY WORDS urban climate analysis; urban planning; urban heat island; urban multi-scale temperature distribution

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Section: Methodsmentioning

confidence: 99%

Estimating spatial patterns of air temperature at building‐resolving spatial resolution in Seoul, Korea

Yi¹,

Kim

et al. 2015

Intl Journal of Climatology

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“…Yi et al [31] noted that such spatial differences are attributable to different shapes and sizes of urban surface components. Earlier studies have attributed such temperature deviations to temperature decline through cold air generation due to higher albedo in vegetated surfaces and the increase in sensible heat release into the atmosphere from building surfaces during the night, depending on the surface area ratio [44,45]. In the case of LDAPS, AWS-dependent temperature variations appeared at dawn to a greater extent than during the daytime, owing to a higher thermal effect of land use.…”

Section: Accuracy Evaluation Of Minimum Temperature During a Tropicalmentioning

confidence: 96%

Statistical Downscaling of Urban-scale Air Temperatures Using an Analog Model Output Statistics Technique

Shin

2019

Atmosphere

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This study was conducted to evaluate the suitability of an analog model output statistics (MOS) downscaling technique for urban-scale meteorology research and compares this MOS-Analog technique with the sliding window technique. We downscaled air temperatures forecasted for the Seoul metropolitan area from 1.5 km resolution (using data from the Unified Model-Local Data Assimilation and Prediction System, UM-LDAPS) to 25 m resolution using the analog MOS technique described in the paper. The support vector machine (SVM) technique was employed for empirical computational modeling, using urban surface parameters calculated using the Climate Analysis Seoul (CAS) workbench and automated weather station (AWS) observational data as training data. The comparison of the downscaled prediction results with the AWS observations for the periods of July/August 2016 and 2017 resulted in a lower root mean square error (RMSE) and higher correlation coefficients (CC) than those obtained for the LDAPS prediction results. The prediction performance was also stable for September, during which precipitation episodes and seasonal fluctuations occurred. The results of this study demonstrate that the proposed technique, which overcomes the limitations of the sliding window technique, is applicable to urban-scale meteorology research and potentially applicable other areas.

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“…The average building height is 20.55 m, and the height of the tallest building is 222.16 m above ground level. The airborne light detection and ranging (lidar) data scanned in 2009 with a density of approximately 25 points per square meter by the South Korea National Geographic Information Institute (NGII) are used to create a coarser-gridded elevation map with a 5-m resolution (Yi et al 2012). There is a 4-yr time difference between the scanned date and simulation target time (2013).…”

Section: Model Description and Simulation Setupmentioning

confidence: 99%

Application of the Cell Perturbation Method to Large-Eddy Simulations of a Real Urban Area

Lee

Muñoz‐Esparza

et al. 2019

Journal of Applied Meteorology and Climatology

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With the continuous increase in computing capabilities, large-eddy simulation (LES) has recently gained popularity in applications related to flow, turbulence, and dispersion in the urban atmospheric boundary layer (ABL). Herein, we perform high-resolution building-scale LES over the Seoul, South Korea, city area to investigate the impact of inflow turbulence on the resulting turbulent flow field in the urban ABL. To that end, LES using the cell perturbation method for inflow turbulence generation is compared to a case where no turbulence fluctuations in the incoming ABL are present (unperturbed case). Validation of the model results using wind speed and wind direction observations at 3 m above ground level reveals minimal differences irrespective of the presence of incoming ABL turbulence. This is due to the high density of building structures present at the surface level that create shear instabilities in the flow field and therefore induce local turbulence production. In the unperturbed case, turbulent fluctuations are found to slowly propagate in the vertical direction with increasing fetch from the inflow boundaries, creating an internal boundary layer that separates the turbulent region near the building structures and the nonturbulent flow aloft that occupies the rest of the ABL. Analysis of turbulence quantities including energy spectra, velocity correlations, and passive scalar fluxes reveals significant underpredictions that rapidly grow with increasing height within the ABL. These results demonstrate the need for realistic inflow turbulence in building-resolving LES modeling to ensure proper interactions within the ABL.

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Improvement of Air Temperature Analysis by Precise Spatial Data on a Local-scale - A Case Study of Eunpyeong New Town in Seoul -

Cited by 15 publications

References 2 publications

Estimating spatial patterns of air temperature at building‐resolving spatial resolution in Seoul, Korea

Estimating spatial patterns of air temperature at building‐resolving spatial resolution in Seoul, Korea

Statistical Downscaling of Urban-scale Air Temperatures Using an Analog Model Output Statistics Technique

Application of the Cell Perturbation Method to Large-Eddy Simulations of a Real Urban Area

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