Thermal assessment of redevelopment in a school playground by UAV with a non-radiometric IR camera and on-site measurements.

Under the impetus of public policy, many school playgrounds are being renovated. Soils are drained of water, buildings are insulated and the planting of vegetation brings eco-systemic benefits that are appreciated by schoolchildren.

As part of a partnership with the local authority, the IATUS project aims to measure the impact of these changes on thermal comfort. The originality of this work consisted in combining measurements with a comfort measurement station to measure UTCI with surface infrared mapping carried out by drone. For cost reasons, the infrared camera used (Flir Vue pro) could not be used to acquire temperatures, but only to obtain numerical values proportional to surface temperatures. In order to calculate surface temperatures, we designed a characterization protocol using large ground targets whose thermal properties were measured in laboratory. We studied two methods of evaluating surface temperatures (linear vs Planck's law). Two field campaigns took place in the courtyard: the first one in july 2021, before the redevelopment, the second in June 2023.

On-site measurements were taken at several locations in the courtyard to take account of the microclimates that drive thermal comfort.

We were able to show that it was possible to estimate thermal comfort on a hot day and make the link with surface temperatures at low cost. Moreover, results show the positive impact of the redevelopment, in particular an improvement in comfort towards the vegetated areas.