scholarly journals Modified RAMS-Urban Canopy Model for Heat Island Simulation in Chongqing, China

2008 ◽  
Vol 47 (2) ◽  
pp. 509-524 ◽  
Author(s):  
Hongbin Zhang ◽  
Naoki Sato ◽  
Takeki Izumi ◽  
Keisuke Hanaki ◽  
Toshiya Aramaki
Keyword(s):  
Urban Canopy ◽  
Heat Emission ◽  
Atmospheric Modeling ◽  
Anthropogenic Heat ◽  
Urban Region ◽  
Infinite Length ◽  
Heat Island ◽  
Urban Canopy Model ◽  
Canopy Model ◽  
Anthropogenic Heat Emission

Abstract A single-layer urban canopy model was integrated into a nonhydrostatic meteorological model, the Regional Atmospheric Modeling System (RAMS). In the new model, called RAMS-Urban Canopy (RAMS-UC), anthropogenic heat emission was also considered. The model can be used to calculate radiation, heat, and water fluxes in an urban area, considering the geometric structure and thermodynamic characteristics of the urban canopy. The urban canopy was represented by normalized street canyons of infinite length, which were bordered by buildings on both sides. The urban region was covered by three types of surfaces: roof, wall, and road. Anthropogenic heat was emitted from these surfaces. Sensitivity tests between the original RAMS and the modified one were carried out by simulating the urban heat island (UHI) of Chongqing, located in an inland mountainous region in China. The results of the model were also compared with the observational data. It was found that the original model could not accurately simulate the UHI, in particular at night, whereas the accuracy was significantly improved in the RAMS-UC. The improvement is substantial even when anthropogenic heat emission is set to zero.

A New Modeling Approach to Forecast Building Energy Demands During Extreme Heat Events in Complex Cities

2011 ◽  
Author(s):  
Estatio Gutie´rrez ◽  
Jorge E. Gonza´lez ◽  
Robert Bornstein ◽  
Mark Arend ◽  
Alberto Martilli
Keyword(s):  
Urban Heat Island ◽  
Heat Wave ◽  
Extreme Event ◽  
Large City ◽  
Urban Canopy ◽  
Anthropogenic Heat ◽  
Heat Island ◽  
Urban Canopy Model ◽  
Urban Heat ◽  
Canopy Model

The thermal response of a large city including the energy production aspects of it are explored for a large and complex city using urbanized atmospheric mesoscale modeling. The Weather Research and Forecasting (WRF) mesocale model is coupled to a multi-layer urban canopy model that considers thermal and mechanical effects of the urban environment including a building scale energy model to account for anthropogenic heat contributions due to indoor-outdoor temperature differences. This new urban parameterization is used to evaluate the evolution and the resulting urban heat island formation associated to a 3-day heat wave in New York City (NYC) during the summer of 2010. High resolution (250 m.) urban canopy parameters (UCPs) from the National Urban Database were employed to initialize the multi-layer urban parameterization. The precision of the numerical simulations is evaluated using a range of observations. Data from a dense network of surface weather stations, wind profilers and Lidar measurements are compared to model outputs over Manhattan and its surroundings during the 3-days event. The thermal and drag effects of buildings represented in the multilayer urban canopy model improves simulations over urban regions giving better estimates of the surface temperature and wind speed. An accurate representation of the nocturnal urban heat island registered over NYC in the event was obtained from the improved model. The accuracy of the simulation is further assessed against more simplified urban parameterizations models with positive results with new approach. Results are further used to quantify the energy consumption of the buildings during the heat wave, and to explore alternatives to mitigate the intensity of the UHI during the extreme event.

A New Modeling Approach to Forecast Building Energy Demands During Extreme Heat Events in Complex Cities

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Estatio Gutiérrez ◽  
Jorge E. González ◽  
Robert Bornstein ◽  
Mark Arend ◽  
Alberto Martilli
Keyword(s):  
Urban Heat Island ◽  
Heat Wave ◽  
Extreme Event ◽  
Surface Air Temperature ◽  
Urban Canopy ◽  
Anthropogenic Heat ◽  
Heat Island ◽  
Urban Canopy Model ◽  
Urban Heat ◽  
Canopy Model

The thermal response of a large and complex city including the energy production aspects of it are explored using urbanized atmospheric mesoscale modeling. The Weather Research and Forecasting (WRF) Mesocale model is coupled to a multilayer urban canopy model that considers thermal and mechanical effects of the urban environment including a building scale energy model to account for anthropogenic heat contributions due to indoor–outdoor temperature differences. This new urban parameterization is used to evaluate the evolution and the resulting urban heat island (UHI) formation associated to a 3-day heat wave in New York City (NYC) during the summer of 2010. High-resolution (250 m) urban canopy parameters (UCPs) from the National Urban Database were employed to initialize the multilayer urban parameterization. The precision of the numerical simulations is evaluated using a range of observations. Data from a dense network of surface weather stations, wind profilers, and Lidar measurements are compared to model outputs over Manhattan and its surroundings during the 3-days event. The thermal and drag effects of buildings represented in the multilayer urban canopy model improves simulations over urban regions giving better estimates of the 2 m surface air temperature and 10 m wind speed. An accurate representation of the nocturnal urban heat island registered over NYC in the event was obtained from the improved model. The accuracy of the simulation is further assessed against more simplified urban parameterizations models with positive results with new approach. Results are further used to quantify the energy consumption of the buildings during the heat wave, and to explore alternatives to mitigate the intensity of the UHI during the extreme event.

scholarly journals Thermal Effects of Urban Canyon Structure on the Nocturnal Heat Island: Numerical Experiment Using a Mesoscale Model Coupled with an Urban Canopy Model

2004 ◽  
Vol 43 (12) ◽  
pp. 1899-1910 ◽  
Author(s):  
Hiroyuki Kusaka ◽  
Fujio Kimura
Keyword(s):  
Heat Capacity ◽  
Urban Canopy ◽  
Urban Canyon ◽  
View Factor ◽  
Heat Island ◽  
Urban Canopy Model ◽  
Maximum Increase ◽  
Sky View Factor ◽  
The Difference ◽  
Canopy Model

Abstract A single-layer urban canopy model is incorporated into a simple two-dimensional atmospheric model in order to examine the individual impacts of anthropogenic heating, a large heat capacity, and a small sky-view factor on mesoscale heat island formation. It is confirmed that a nocturnal heat island on a clear, calm summer day results from the difference in atmospheric stability between a city and its surroundings. The difference is caused by anthropogenic heating and the following two effects of urban canyon structure: (i) a larger heat capacity due to the walls and (ii) a smaller sky-view factor. Sensitivity experiments show that the anthropogenic heating increases the surface air temperature though the day. (This factor strongly affects the nocturnal temperature, and the maximum increase of 0.67°C occurs at 0500 LST.) The larger heat capacity due to the walls decreases the daytime temperature and increases the nocturnal temperature. (The maximum increase of 0.39°C occurs at 0600 LST.) The smaller sky-view factor increases the temperature though the day, particularly during the first several hours after sunset. (The maximum increase of 0.52°C occurs at midnight.) In urban areas, this factor results in uniform cooling that occurs at a constant rate. The impact of the canyon structure is shown to be as significant as anthropogenic heating.

scholarly journals Impact of an improved WRF urban canopy model on diurnal air temperature simulation over northern Taiwan

2016 ◽  
Vol 16 (3) ◽  
pp. 1809-1822 ◽  
Author(s):  
Chuan-Yao Lin ◽  
Chiung-Jui Su ◽  
Hiroyuki Kusaka ◽  
Yuko Akimoto ◽  
Yang-Fan Sheng ◽  
...  
Keyword(s):  
Land Surface ◽  
Urban Areas ◽  
Urban Canopy ◽  
Anthropogenic Heat ◽  
Surface Model ◽  
Urban Canopy Model ◽  
Simulation Performance ◽  
The Impact ◽  
Canopy Model ◽  
Northern Taiwan

Abstract. This study evaluates the impact of urbanization over northern Taiwan using the Weather Research and Forecasting (WRF) Model coupled with the Noah land-surface model and a modified urban canopy model (WRF–UCM2D). In the original UCM coupled to WRF (WRF–UCM), when the land use in the model grid is identified as "urban", the urban fraction value is fixed. Similarly, the UCM assumes the distribution of anthropogenic heat (AH) to be constant. This may not only lead to over- or underestimation of urban fraction and AH in urban and non-urban areas, but spatial variation also affects the model-estimated temperature. To overcome the abovementioned limitations and to improve the performance of the original UCM model, WRF–UCM is modified to consider the 2-D urban fraction and AH (WRF–UCM2D).The two models were found to have comparable temperature simulation performance for urban areas, but large differences in simulated results were observed for non-urban areas, especially at nighttime. WRF–UCM2D yielded a higher correlation coefficient (R2) than WRF–UCM (0.72 vs. 0.48, respectively), while bias and RMSE achieved by WRF–UCM2D were both significantly smaller than those attained by WRF–UCM (0.27 and 1.27 vs. 1.12 and 1.89, respectively). In other words, the improved model not only enhanced correlation but also reduced bias and RMSE for the nighttime data of non-urban areas. WRF–UCM2D performed much better than WRF–UCM at non-urban stations with a low urban fraction during nighttime. The improved simulation performance of WRF–UCM2D in non-urban areas is attributed to the energy exchange which enables efficient turbulence mixing at a low urban fraction. The result of this study has a crucial implication for assessing the impacts of urbanization on air quality and regional climate.

scholarly journals Explore the Accuracy of the Pedestrian Level Temperature Estimated by the Combination of LCZ with WRF Urban Canopy Model through the Microclimate Measurement Network

2021 ◽  
Vol 8 (1) ◽  
pp. 14
Author(s):  
Yu-Cheng Chen ◽  
Fang-Yi Cheng ◽  
Cheng-Pei Yang ◽  
Tzu-Ping Lin
Keyword(s):  
Heat Capacity ◽  
Urban Development ◽  
Urban Climate ◽  
Urban Canopy ◽  
Subtropical Climate ◽  
Heat Island ◽  
Urban Canopy Model ◽  
Urban Heat ◽  
The City ◽  
Canopy Model

Due to the urban heat island effect becoming more evident in the cities in Taiwan, the urban climate has become an essential factor in urban development. Taiwan is located on the border of tropical and subtropical climate zones, the climate condition is hot and humid, and the city shows high-density development. The dense urban development has increased the heat storage capacity of the ground and buildings. However, if only the climate stations set by the Central Meteorological Bureau to observe the climate data are applied, the predicted results differ from the actual urban climate conditions due to the small number of these stations and the too far distance between them. Therefore, this study employs the local climate zone (LCZ), which can classify the land features by considering both land use and land cover, and can be freely generated from satellite images. The LCZ classification method can view the type of the city through the height and density of obstacles. This study also combines the urban canopy model (UCM) of the mesoscale climate prediction model and weather research and forecasts (WRF). This approach can calculate vertical and horizontal planes of the city, such as building volume, road width, the influence of streets and roofs, roof heat capacity, building wall heat capacity, etc., to predict the climatic conditions in different lands in the study area. Simultaneously, to understand the actual distribution of urban climate more accurately, this study used the microclimate measurement network built in the research area to produce pedestrian-level temperature distribution and compared the estimated results with the actual measured values for urban climate assessment. This study can understand the cause of urban heat islands and assist urban planners more appropriately formulate heat island mitigation strategies in different regions.

Sign in / Sign up

Export Citation Format

Share Document