It heated up at ICUC Urban Climate conference


Matthias Ratheiser,
Executive Director Weatherpark

Matthias Ratheiser, executive director of Weatherpark, reports from the international urban climate conference in Toulouse.

You attended the latest „International Conference on Urban Climate“ (ICUC) in France. What were the issues at this conference?
500 urban climate researchers from five continents exchanged views in the form of lectures, panel discussions and workshops.

On which topics?
Generally, the development of processes related to urban climate, in particular urban heat islands, vegetation in the city and air quality. For instance, a possible irrigation management for trees in times of high heat and the drought that comes with it was discussed. And a city’s influence on the weather, especially on thunderstorms. Or the cross-linking of different temperature sensors, which is a long way off.

What do the scientists and experts wish to achieve?
The aim is that human beings feel comfortable in terms of solar radiation, temperature, wind and ventilation. Measures are searched to establish liveable urban areas. This topic gains in importance as a consequence of the global climate change.

Has this research already brought results?
There are new findings on an ongoing basis. Different computational models are used to find out the influence of various factors on the climate.

Which factors can these be?
The brightness of materials, for example. In simulations all roofs of a city are assumed white and then the effects on the temperature in the city are examined.

Can such a model be put into practice as well?
For a whole town the measures that are simulated in a model can be implemented rather rarely. But new building projects can be planned in such a way that the human comfort is high: precisely by using bright materials for floors and buildings, further by measures for improved shadowing, by strategically positioned water areas and green spaces etc. Real estate and open areas then heat up less, which in turn leads to lower temperatures at night.

Are temperatures at night relevant? It is cooler then, anyway…
It is cooler than during the day, but usually not cool enough to sleep well. It has been found out that sleep is crucial for quality of life. And the less a city heats up during the day, the cooler it is then during the night.

Which other factors influence the urban climate in addition?
Ventilation plays a vital role. Cool fresh air should be able to flow in the city without being stopped by high rise buildings.

Here, arguably city planners are required. Do cities already work together regularly with meteorologists?
Yes, in part. Of course, we at Weatherpark wish for more interaction. It would be nice if there were more real and virtual places where city planners, developers, architects and meteorologists could exchange views on a regular basis and develop a strategy or a plan together.

What can such a cooperation look like in particular cases?
The cooperation could begin before the actual planning of squares, buildings or urban districts. Meteorologists study the area to be developed and make recommendations regarding the alignment and design of real estate and open spaces. As soon as concrete plans are available these can be optimized in detail. Shady trees at the right places, accessible water areas and a gentle breeze can make heat more pleasant at once. In the end, buildings and squares are designed in such a way that residents and passers-by feel comfortable even with temperatures beyond 35 °C.

But it seldom gets that hot in central Europe…
More and more often! The past summer brought Vienna 17 days with temperatures beyond 35 °C. Everybody was groaning under the heat. The climate change is in full swing, which we felt clearly this year. But with the right adjustment measures for our cities they will remain worth living.