A masked Toulousaine on the Place du Capitole, on a sunny day.
F. Scheiber - Sipa
In Toulouse, 15 new weather sensors will be installed to refine the data on the famous urban heat islands.
The former have already delivered their verdict and show that the suburbs are more exposed to the heat.
The new cartography should serve as a guide, or corrector, for urban development.
If you are one of those Toulouse residents who no longer go out without their mittens and earmuffs in these frosty morning weather, rest assured, it is even colder in the surrounding countryside: 3 ° less on average.
In any case, this is the observation made thanks to the 60 weather sensors deployed on the territory of the metropolis.
In collaboration with the Météo-France Research Center, their data - available in Open Data for those interested in statistics - allow metropolitan services to study the now well-known phenomenon of “urban heat islands”.
This propensity of soils and buildings to store heat is becoming more problematic now that scorching episodes, in summer and even sometimes in spring, are on the increase.
2 ° C higher on average
Fifteen new sensors must be installed by the summer, but the "winding" of the data has already delivered a first verdict: "In summer, two hours after sunset, it is on average 2 ° C higher. in Toulouse than in the countryside, in the Bouconne forest for example ”underlines François Chollet, vice-president of the metropolis responsible for sustainable development.
The temperature difference can be much greater, especially in the suburbs, Busca or Minimes to name a few.
And, logically, the sensors confirm that urban parks fulfill their role of islands of freshness.
Life-size experience at Le Ramier
So what can this mapping, which is being expanded with the expertise of Météo-France, be used for?
"To nourish the reflection in terms of development, to be integrated for example into the local inter-municipal urban plan (PLUIH)", answers the elected official.
And first of all to identify the sectors where it is necessary to act as a priority, sometimes removing bitumen or concrete.
A life-size experiment is currently being carried out in parallel with the deconstruction of the Parc des Expositions on Île du Ramier.
"We are launching a" debitumization ", recalls François Chollet, and the comparison of the data before and after will show us its effect.
The sensors will also be able to make it possible to evaluate the relevance of a particular arrangement a posteriori.
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