Corrigendum to ‘Pathway using WUDAPT's Digital Synthetic City tool towards generating urban canopy parameters for multi-scale urban atmospheric modeling’ [Urban Climate 28 (2019) 100459]

Abstract. As most of the population lives in urban environments, the simulation of the urban climate has become a key problem in the framework of the climate change impact assessment. However, the high computational power required by these simulations is a severe limitation. Here we present a study on the performance of a Urban Climate Model (UrbClim), designed to be several orders of magnitude faster than a full-fledge mesoscale model. The simulations are validated with station data and with land surface temperature observations retrieved by satellites. To explore the advantages of using a simple model like UrbClim, the results are compared with a simulation carried out with a state-of-the-art mesoscale model, the Weather Research and Forecasting model, using an Urban Canopy model. The effect of using different driving data is explored too, by using both relatively low resolution reanalysis data (70 km) and a higher resolution forecast model (15 km). The results show that, generally, the performance of the simple model is comparable to or better than the mesoscale model. The exception are the winds and the day-to-day correlation in the reanalysis driven run, but these problems disappear when taking the boundary conditions from the higher resolution forecast model.

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Urban Climate Multi-Scale Modelling in Bilbao (Spain): A Review

Procedia Engineering ◽

10.1016/j.proeng.2015.07.348 ◽

2015 ◽

Vol 115 ◽

pp. 3-11 ◽

Cited By ~ 3

Author(s):

J.A. Acero ◽

S. Kupski ◽

J. Arrizabalaga ◽

L. Katzschner

Keyword(s):

Urban Climate ◽

Multi Scale ◽

Scale Modelling

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Modelling of sensible heat flux from urban canopy to atmosphere for urban climate prediction

ENVIRONMENTAL SYSTEMS RESEARCH ◽

10.2208/proer1988.26.483 ◽

1998 ◽

Vol 26 ◽

pp. 483-486

Author(s):

Akira URANO ◽

Keisuke HANAKI ◽

Hiroki KONAKAWA

Keyword(s):

Heat Flux ◽

Urban Climate ◽

Sensible Heat Flux ◽

Urban Canopy ◽

Climate Prediction ◽

Sensible Heat

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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

Sustainability ◽

10.3390/su12051737 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1737 ◽

Cited By ~ 2

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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Advantages of using a fast urban boundary layer model as compared to a full mesoscale model to simulate the urban heat island of Barcelona

Geoscientific Model Development ◽

10.5194/gmd-9-4439-2016 ◽

2016 ◽

Vol 9 (12) ◽

pp. 4439-4450 ◽

Cited By ~ 6

Author(s):

Markel García-Díez ◽

Dirk Lauwaet ◽

Hans Hooyberghs ◽

Joan Ballester ◽

Koen De Ridder ◽

...

Keyword(s):

Boundary Layer ◽

Simple Model ◽

Wind Speed ◽

Mesoscale Model ◽

Urban Climate ◽

Urban Canopy ◽

Forecast Model ◽

Heat Island ◽

Layer Model ◽

Urban Heat

Abstract. As most of the population lives in urban environments, the simulation of the urban climate has become a key problem in the framework of the climate change impact assessment. However, the high computational power required by high-resolution (sub-kilometre) fully coupled land–atmosphere simulations using urban canopy parameterisations is a severe limitation. Here we present a study on the performance of UrbClim, an urban boundary layer model designed to be several orders of magnitude faster than a full-fledged mesoscale model. The simulations are evaluated with station data and land surface temperature observations from satellites, focusing on the urban heat island (UHI). To explore the advantages of using a simple model like UrbClim, the results are compared with a simulation carried out with a state-of-the-art mesoscale model, the Weather Research and Forecasting Model, which includes an urban canopy model. This comparison is performed with driving data from ERA-Interim reanalysis (70 km). In addition, the effect of using driving data from a higher-resolution forecast model (15 km) is explored in the case of UrbClim. The results show that the performance of reproducing the average UHI in the simple model is generally comparable to the one in the mesoscale model when driven with reanalysis data (70 km). However, the simple model needs higher-resolution data from the forecast model (15 km) to correctly reproduce the variability of the UHI at a daily scale, which is related to the wind speed. This lack of accuracy in reproducing the wind speed, especially the sea-breeze daily cycle, which is strong in Barcelona, also causes a warm bias in the reanalysis driven UrbClim run. We conclude that medium-complexity models as UrbClim are a suitable tool to simulate the urban climate, but that they are sensitive to the ability of the input data to represent the local wind regime. UrbClim is a well suited model for impact and adaptation studies at city scale without high computing requirements, but does not replace the need for mesoscale atmospheric models when the focus is on the two-way interactions between the city and the atmosphere.

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15 year re-analysis of the urban climate of Amsterdam using WRF

10.5194/egusphere-egu2020-11560 ◽

2020 ◽

Author(s):

Sytse Koopmans ◽

Gert-Jan Steeneveld ◽

Ronald van Haren ◽

Albert Holtslag

Keyword(s):

Data Assimilation ◽

The Netherlands ◽

Thermal Comfort ◽

Prediction Models ◽

Weather Prediction ◽

Urban Climate ◽

Urban Canopy ◽

Human Thermal Comfort ◽

Weather Observations ◽

Simulated Precipitation

15 year re-analysis of the urban climate of Amsterdam using WRF &#160;Sytse Koopmans1 ([email protected]), Gert-Jan Steeneveld1, Ronald van Haren2, Albert A.M. Holtslag1.&#160;1 Wageningen University and Research, the Netherlands:2 Netherlands eScience Center, the Netherlands:&#160;&#160;Ongoing world-wide climate change and urbanization illustrate the need to understand urban hydrometeorology and its implications for human thermal comfort and water management. Numerical weather prediction models can assist to understand these issues, as they progress increasingly towards finer scales. With high model resolutions (grid spacing of 100m), effective representation of cities becomes crucial. The complex structures of cities, configuration of buildings, streets and scattered vegetation, require a different modelling approach than the homogeneous rural surroundings. The current urban canopy-layer schemes account for these city specific characteristics, but differ substantially amongst each other due to uncertainty in land use parameters and incomplete physical understanding. Therefore, the hindcasting of the urban environment needs improvement.In this study, we improve the WRF (Weather Research and Forecasting) mesoscale model performance by incorporating observations of a variety of sources using data assimilation (WRF-3DVAR) and nudging techniques on a resolution up to 167 meter. Data assimilation aims to accurately describe the most probable atmospheric state by steering the model fields in the direction of the observations. Specific to urban boundary layers, a novel approach has been developed to nudge modelled urban canyon temperatures with quality controlled urban weather observations. Adjusting the urban fabric accordingly is crucial, because of the large heat storage within urban canopies. The road and wall layers of the urban canopy are adjusted depending on the bulk heat transfer coefficient and urban geometry. Other data assimilation sources consists of WMO synoptic weather observations and volume radar data.The results of the 15-year climatological urban re-analysis are here presented and it is subdivided in three key questions. First, we attempt to answer how large the trends are in human thermal comfort over the 15 year period. Second, we investigate if there are seasonality&#8217;s detected in maximum urban heat island intensities. Earlier found hysteresis-like curves were reproduced to a large extent for for pedestrian level air temperatures. Lastly, we analyse trends in extreme precipitation using simulated precipitation data on one second interval.

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

Journal of Applied Meteorology and Climatology ◽

10.1175/2007jamc1397.1 ◽

2008 ◽

Vol 47 (2) ◽

pp. 509-524 ◽

Cited By ~ 25

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.

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