Urban Climate Analysis Map of Arnhem
Cities in The Netherlands face the UHI-effect too. This is demonstrated by the preliminary results of measurements in August 2009, carried out by Wageningen University. Both in Arnhem as in Rotterdam, temperature measurements have taken place after a series of very hot days. In both cities the same temperature differences were found, up to 7 ºC between areas inside and outside the cities. This indicates that there is indeed an UHI-effect in Dutch cities. The size of the city seems to be of no big importance. But what is the mechanism behind this effect? Information from international and national research helped us to identify the main aspects.
We identified five, strongly related, factors which causes the UHI-effect:
- Topography
- Land use;
- Urban morphology (building volume and heights; dimensions of the public or open space);
- Material use and colour;
- Wind path.
In essence, two mechanisms are involved:
- The extent in which heat is stored in the city
- The extent of possibilities to cool the city
With these five factors we have constructed the ‘Urban Climate Analysis Map’ (UCAMap) or heat map. The UCAMap identifies the areas of heat storage. This map shows, in one glance, opportunities to solve the UHI-effect as well as (possible) problems.
The Urban Climate Analysis Map shows us the balance of heat and ventilation:
- Which areas of the city are at most risk for heat storage and have, due to their structure (morphology), difficulties to cool in the evening and especially at night ‘on its own’?
- What are possibilities to ventilate (parts of) the city to cool the city during daytime and especially at night?
[lees meer in "FUTURE CITIES Analyse van het hitte-eilandeffect op Arnhem"]
- Urban Climate Analysis Map of Arnhem
With this heat map we visualised the effects of Urban Heat in Arnhem.
The next step is to determine the consequences of the UHI-effect for the city of Arnhem. Are they ‘serious, must we speak in terms of an “undesired situation” or are there even health risks? We determine the urgency to act and take adaptive measures. We are now at the point to bring this together in an ‘Urban Climate Recommendation Map’, that shows us how we can reduce heat storage and improve cooling options. A necessary step to take taking into account that due to climate change the UHI-effect will get stronger.
This information we want to use in setting up our new spatial plan of the city of Arnhem (Dutch: structuurvisie) but also in actual and planned urban developments. We may have to preserve, protect certain green and blue areas to prevent disturbance of cooling air paths, be aware not to built-over already quite densely built-up areas and advise to extend the greening of areas. In the Future Cities project we also work on a toolbox, that provides governmental organisations like municipalities, regional authorities and provinces to make the right, cost-effective, adaptive measures to prevent undesirable consequences of the heating up of their cities.
<to be continued>
Downloads
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Urban Climate Analysis Map of Arnhem |
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report_Urban_Climatic_Map_of_Arnhem_City.pdf In this report the making of an urban climate map for the city of Arnhem is presented. |
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Urban_climatic_map_studies__a_review.pdf Paper "urban climatic map studies: a review" |
