Multilayer urban canopy modelling and mapping for traffic pollutant dispersion at high density urban areas

2019 ◽  
Vol 647 ◽  
pp. 255-267 ◽  
Author(s):  
Chao Yuan ◽  
Ruiqin Shan ◽  
Yangyang Zhang ◽  
Xian-Xiang Li ◽  
Tiangang Yin ◽  
...  
Keyword(s):  
Urban Areas ◽  
Urban Canopy ◽  
Pollutant Dispersion ◽  
High Density

scholarly journals High-Resolution Simulations of the Urban Thermal Climate in Suzhou City, China

Atmosphere ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 118
Author(s):  
Yan Chen ◽  
Ning Zhang ◽  
Yan Zhu
Keyword(s):  
High Resolution ◽  
Urban Areas ◽  
Urban Climate ◽  
Urban Canopy ◽  
High Density ◽  
Urban Heat Islands ◽  
Medium Density ◽  
Heat Islands ◽  
Thermal Climate ◽  
Urban Heat

City thermal discomfort conditions have been exacerbated by the rapid urbanization processes in China. High-resolution urban thermal climate simulations can help us to understand urban climate features and produce better urban designs. In this paper, a single-layer urban canopy model (UCM) combined with Landsat satellite data and high-resolution meteorological forcing data was used to simulate very-high-resolution characteristics of temperature and humidity at the urban canopy level, and the heat index at the pedestrian level was also estimated. The research shows that the National center of environmental forecasting, Oregon state university, Air force and Hydrological research lab (NOAH)-UCM model can simulate the distribution of meteorological elements for different land uses in a fine and effective manner, making it an effective approach to obtaining the fundamental data for urban climate analysis. The spatial distribution pattern of urban heat islands in Suzhou is highly consistent with urban land cover fraction. High-density and medium-density urban areas are centers of urban heat islands, and the annual number of high-temperature days and heat indices over the high-density and medium-density urban areas are markedly higher than those in low-density cities and suburbs, indicating that urban development has a significant impact on the urban thermal environment.

Predictive Model of Rainfall-Induced Landslides in High-Density Urban Areas of the South Primorsky Region (Russia)

2021 ◽  
Author(s):  
Yu. A. Stepnova ◽  
A. A. Stepnov ◽  
A. V. Konovalov ◽  
Yu. V. Gensiorovskiy ◽  
V. A. Lobkina ◽  
...  
Keyword(s):  
Predictive Model ◽  
Urban Areas ◽  
High Density ◽  
The South

scholarly journals Evaluating the Urban Canopy Scheme TERRA_URB in the COSMO Model for Selected European Cities

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 237 ◽  
Author(s):  
Valeria Garbero ◽  
Massimo Milelli ◽  
Edoardo Bucchignani ◽  
Paola Mercogliano ◽  
Mikhail Varentsov ◽  
...  
Keyword(s):  
Urban Areas ◽  
Morphological Characteristics ◽  
Urban Canopy ◽  
Anthropogenic Heat ◽  
Climate Modelling ◽  
Model Framework ◽  
European Cities ◽  
Cosmo Model ◽  
Anthropogenic Heat Flux ◽  
Urban Heat

The increase in built surfaces constitutes the main reason for the formation of the Urban Heat Island (UHI), that is a metropolitan area significantly warmer than its surrounding rural areas. The urban heat islands and other urban-induced climate feedbacks may amplify heat stress and urban flooding under climate change and therefore to predict them correctly has become essential. Currently in the COSMO model, cities are represented by natural land surfaces with an increased surface roughness length and a reduced vegetation cover, but this approach is unable to correctly reproduce the UHI effect. By increasing the model resolution, a representation of the main physical processes that characterize the urban local meteorology should be addressed, in order to better forecast temperature, moisture and precipitation in urban environments. Within the COSMO Consortium a bulk parameterization scheme (TERRA_URB or TU) has been developed. It parametrizes the effects of buildings, streets and other man-made impervious surfaces on energy, moist and momentum exchanges between the surface and atmosphere, and additionally accounts for the anthropogenic heat flux as a heat source from the surface to the atmosphere. TU implements an impervious water-storage parameterization, and the Semi-empirical Urban canopy parametrization (SURY) that translates 3D urban canopy into bulk parameters. This paper presents evaluation results of the TU scheme in high-resolution simulations with a recent COSMO model version for selected European cities, namely Turin, Naples and Moscow. The key conclusion of the work is that the TU scheme in the COSMO model reasonably reproduces UHI effect and improves air temperature forecasts for all the investigated urban areas, despite each city has very different morphological characteristics. Our results highlight potential benefits of a new turbulence scheme and the representation of skin-layer temperature (for vegetation) in the model performance. Our model framework provides perspectives for enhancing urban climate modelling, although further investigations in improving model parametrizations, calibration and the use of more realistic urban canopy parameters are needed.

scholarly journals Review on pollutant dispersion in urban areas-part A: Effects of mechanical factors and urban morphology

2021 ◽  
Vol 190 ◽  
pp. 107534
Author(s):  
Zhengtong Li ◽  
Tingzhen Ming ◽  
Shurong Liu ◽  
Chong Peng ◽  
Renaud de Richter ◽  
...  
Keyword(s):  
Urban Areas ◽  
Pollutant Dispersion ◽  
Urban Morphology ◽  
Mechanical Factors

scholarly journals A Quantitative Method for Evaluation of Visual Privacy in Residential Environments

Buildings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 272
Author(s):  
He Zheng ◽  
Bo Wu ◽  
Heyi Wei ◽  
Jinbiao Yan ◽  
Jianfeng Zhu
Keyword(s):  
Urban Areas ◽  
Architectural Design ◽  
Ground Level ◽  
High Density ◽  
Rapid Expansion ◽  
High Rise ◽  
Visual Exposure ◽  
Building Management ◽  
Visual Privacy ◽  
Building Level

With the rapid expansion of high-rise and high-density buildings in urban areas, visual privacy has become one of the major concerns affecting human environmental quality. Evaluation of residents’ visual exposure to outsiders has attracted more attention in the past decades. This paper presents a quantitative indicator; namely, the Potential Visual Exposure Index (PVEI), to assess visual privacy by introducing the damage of potential visual incursion from public spaces and neighborhoods in high-density residences. The method for computing the PVEI mainly consists of three steps: extracting targets and potential observers in a built environment, conducting intervisibility analysis and identifying visible sightlines, and integrating sightlines from building level and ground level to compute the PVEI value of each building opening. To validate the proposed PVEI, a case study with a sample building located at the center of Kowloon, Hong Kong, was evaluated. The results were in accordance with the common-sense notion that lower floors are subjected to poor visual privacy, and privacy is relatively well-preserved in upper floors in a building. However, residents of middle floors may suffer the worst circumstances with respect to visual privacy. The PVEI can be a useful indicator to assess visual privacy and can provide valuable information in architectural design, hotel room selection, and building management.

scholarly journals Quantifying the Effects of Urban Form on Land Surface Temperature in Subtropical High-Density Urban Areas Using Machine Learning

2019 ◽  
Vol 11 (8) ◽  
pp. 959 ◽  
Author(s):  
Yanwei Sun ◽  
Chao Gao ◽  
Jialin Li ◽  
Run Wang ◽  
Jian Liu
Keyword(s):  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Urban Form ◽  
Urban Areas ◽  
Thermal Environment ◽  
High Density ◽  
Cooling Effects ◽  
Urban Thermal Environment ◽  
The Impact

It is widely acknowledged that urban form significantly affects urban thermal environment, which is a key element to adapt and mitigate extreme high temperature weather in high-density urban areas. However, few studies have discussed the impact of physical urban form features on the land surface temperature (LST) from a perspective of comprehensive urban spatial structures. This study used the ordinary least-squares regression (OLS) and random forest regression (RF) to distinguish the relative contributions of urban form metrics on LST at three observation scales. Results of this study indicate that more than 90% of the LST variations were explained by selected urban form metrics using RF. Effects of the magnitude and direction of urban form metrics on LST varied with the changes of seasons and observation scales. Overall, building morphology and urban ecological infrastructure had dominant effects on LST variations in high-density urban centers. Urban green space and water bodies demonstrated stronger cooling effects, especially in summer. Building density (BD) exhibited significant positive effects on LST, whereas the floor area ratio (FAR) showed a negative influence on LST. The results can be applied to investigate and implement urban thermal environment mitigation planning for city managers and planners.

scholarly journals Micrometeorological Modeling of Radiative and Convective Effects with a Building-Resolving Code

2011 ◽  
Vol 50 (8) ◽  
pp. 1713-1724 ◽  
Author(s):  
Yongfeng Qu ◽  
Maya Milliez ◽  
Luc Musson-Genon ◽  
Bertrand Carissimo
Keyword(s):  
Urban Areas ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Pollutant Dispersion ◽  
Urban Setting ◽  
Dynamical Model ◽  
Neutral Atmosphere ◽  
Atmospheric Flow ◽  
Ongoing Work ◽  
The One

AbstractIn many micrometeorological studies with computational fluid dynamics, building-resolving models usually assume a neutral atmosphere. Nevertheless, urban radiative transfers play an important role because of their influence on the energy budget. To take into account atmospheric radiation and the thermal effects of the buildings in simulations of atmospheric flow and pollutant dispersion in urban areas, a three-dimensional (3D) atmospheric radiative scheme has been developed in the atmospheric module of the Code_Saturne 3D computational fluid dynamic model. On the basis of the discrete ordinate method, the radiative model solves the radiative transfer equation in a semitransparent medium for complex geometries. The spatial mesh discretization is the same as the one used for the dynamics. This paper describes ongoing work with the development of this model. The radiative scheme was previously validated with idealized cases. Here, results of the full coupling of the radiative and thermal schemes with the 3D dynamical model are presented and are compared with measurements from the Mock Urban Setting Test (MUST) and with simpler modeling approaches found in the literature. The model is able to globally reproduce the differences in diurnal evolution of the surface temperatures of the different walls and roof. The inhomogeneous wall temperature is only seen when using the 3D dynamical model for the convective scheme.

scholarly journals Application of the WRF/Chem v.3.6.1 on the reanalysis of criteria pollutants over Metro Manila

2019 ◽  
Vol 29 (1) ◽  
Author(s):  
Jacob Alberto Garcia ◽  
Edgar Vallar ◽  
Maria Cecilia Galvez ◽  
Gerry Bagtasa
Keyword(s):  
Time Series ◽  
Urban Areas ◽  
Urban Canopy ◽  
Cold Bias ◽  
Canopy Layer ◽  
Criteria Pollutants ◽  
Pollutant Concentrations ◽  
Significant Difference ◽  
Metro Manila ◽  
Student’S T

AbstractMetro Manila, Philippines and other urban areas have reached internationally known unacceptable levels of pollution where about 80% can be attributed to vehicular emissions. The Weather Research and Forecasting model coupled with Chemistry v.3.6.1 was used in the reanalysis of pollutant concentrations for the year 2013. Initial results from the planetary boundary layer study suggested that the Yonsei University scheme provides a good estimate of the atmosphere’s condition; hence, this setting was used for the succeeding simulations. The land coverage over Sangley point was not properly resolved by the model. This caused a cold bias for the station. Further evaluation of the model’s sea level pressure output for all sites returned high correlations showing that modeled values are in phase with the observed time series; however, wind speed values did not correlate well with the observed values and were all overestimated. The low correlations found were a result of the incapability of the model to detect the urban canopy layer over Metro Manila. Pollutant concentrations were overestimated. The pollutant time series suggests that the model overestimates concentration values for PM10, PM2.5, and SO2, while underestimating NO2 and O3 values. However, it does capture a significant 24-hourly cycle as seen in the time series’ spectra in the frequency domain. Furthermore, through a student’s t-test, the model also captures a significant difference in daytime and nighttime concentrations.

scholarly journals Impacts of Urban Form on Thermal Environment Near the Surface Region at Pedestrian Height: A Case Study Based on High-Density Built-Up Areas of Nanjing City in China

2020 ◽  
Vol 12 (5) ◽  
pp. 1737 ◽  
Author(s):  
Junyan Yang ◽  
Beixiang Shi ◽  
Geyang Xia ◽  
Qin Xue ◽  
Shi-Jie Cao
Keyword(s):  
Urban Form ◽  
Thermal Environment ◽  
Urban Climate ◽  
Urban Canopy ◽  
Surface Region ◽  
High Density ◽  
Average Height ◽  
Near Surface ◽  
Building Density ◽  
Thermal Environments

The continuous worsening of urban thermal environments poses a severe threat to human health and is among the main problems associated with urban climate change and sustainable development. This issue is particularly severe in high-density built-up areas. Existing studies on the thermal environments (temperature data extracted from satellite remote sensing images) are mainly focused on urban canopy areas (airspace below the average height of trees or buildings) rather than the near surface region (at pedestrian height). However, the main outdoor activity space of urban residents is the area near surface region. Hence, this study aims to investigate the influence of urban form (i.e., building density, height, and openness) on thermal environment near the surface region. The high-density built-up areas of a typical megacity (i.e., Nanjing) in China were selected, and the thermal environments of 26 typical blocks were simulated using ENVI-met software. Temperature field measurements were carried out for simulation validation. On this basis, a classified and comparative study was conducted by selecting the key spatial form elements that affect thermal environments. The results showed that in actual high-density built-up areas, single urban form parameter does not determine the thermal environments near the urban surface but mainly affected by the use (function) of space. For this study, the overall thermal environment of a street block is optimal when the building density is between 40% and 50% and the average building height is between 8 and 17 stories. Nonetheless, the urban form can be improved to optimize the overall effects on building functions and thermal environments. Furthermore, function-specific urban form optimization strategies were proposed to optimize thermal environments according to specific functional needs.

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