Urban Climate Assessment

Service description

Urban climate policy starts by knowing precisely the climatic conditions inside your city. The urban climate assessment service delivers local policy makers an objective evaluation about the presence and the intensity of the urban heat island in their city. It allows to build up policies and action plans aiming to create more climate-resilient cities. More precisely, it allows to identify the good and not so good neighbourhoods in terms of urban climate.

We developed an urban climate assessment service with a fast modelling assessment that can be complemented –if desired- with a monitoring campaign:

  • UrbClim™ modelling assessment. The UrbClim model allows to calculate the urban heat intensity of any city in the world at a resolution up to 100m. Importantantly, no local input data is needed, all input data is taken from international satellite based land cover, vegetation and soil sealing data and meteorological databases. The model has been optimized for fast assessments while keeping the accuracy at a very high level. The fast modelling also enables long-term (up to 20 year periods) climatological results. The following maps can be delivered:
    • Average urban heat island intensity
    • Average air temperature
    • Average air temperature at midnight (moment with the highest temperature difference between the rural and urban areas)
    • Average number of heat wave days according to any heat wave classification scheme
    • Cooling degree-hours: number of hours above a threshold air temperature as an indication for the cooling energy demand

 

The Urban Heat Island effect can also be measured. VITO has proven expertise in setting up meteorological equipment (fixed stations, mobile urban climate lab), in organising the collection of the data and the processing of the data into maps and indicators. From past projects, we have learned that a map with measured urban heat island values provides an effective communication means with the population.

Finally, a vulnerability assessment can be performed by combining the high resolution urban heat island map with socio-economic and demography data to identify the most vulnerable neighbourhoods. This allows city administrations to develop emergency plans for heat waves response actions as well as long term UHI mitigation strategies with a spatial component by focusing on the most vulnerable areas.

 

 

UrbClim modelling

To evaluate the whole city, the UrbClim model is used to map out the urban heat island intensity at a resolution up to 100 meter.

The UrbClim model, described in the research section, has been validated in many studies. If requested, a specific validation using the UHI measurements allows to estimate the uncertainties on the model results for your city.

Using the UrbClim model, we provide average air temperaures, average nighttime air temperatures, average nighttime minimum air temperatures, number of heat wave days, …

Number of heatwave days during the period 1985 - 2005 for the city of Antwerp according to the definition of the EuroHEAT project (D'Ippoliti et al, 2010)

UHI measurements

Customized meteorological stations and the VITO Mobile Urban Lab are used to collect urban heat island measurements. From the gathered data, a first localized assessment can be provided. The measurement data allows policy makers to communicate effectively about the urban heat island intensity. Although providing local information, it constitutes an undeniable proof.

Inside the Ghent and Antwerp heat island analysis projects, air temperature and wind speed data was collected both from fixed measurement stations and using the Mobile Urban Lab. Mapping the mobile measurements on a map demonstrates the spatial existence of a strong UHI phenomenon. The times series analysis from the fixed measurement stations indicate the high temporal variability and the strong anti-correlation between the wind speed and the UHI-intensity. Maximum values up to 8 degrees Celsius have been measured.

Mobile measurements along a transect crossing the city of Antwerp at September 4th 2013, late evening.
Air temperature and wind speed for Aug. 25th - Sep 14th 2012 for the city of Ghent at 3 urban sites and data from one reference station (KMI Melle). The middle graph shows the temperature difference.

Service demonstration

VITO has demonstrated the Urban Climate Assessment service inside heat island projects for the cities of Tilburg, Antwerp and Ghent. In all cities modelling and monitoring work has been performed for city authorities. More information about the projects can be found in the “Projects” section. 

To prove the fast applicability of the UrbClim model, we have applied the model for more than 100 EU cities. By clicking on the image below, you enter the UrbClim model demonstration page with preliminary results for each city. Attention, the maps are based on data for one-summer only and cannot be used as climatological maps.

 

 

 

Using own research funds, VITO set up an online web-application to monitor the Antwerp UHI-intensity. The demonstrator is currently interrupted due to the move of the urban station but the historic UHI-intensity data can be visualized here.