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

International audience ; Under the impetus of public policy, many school playgrounds are being renovated. Soils are drainedof water, buildings are insulated and the planting of vegetation brings eco-systemic benefits that areappreciated by schoolchildren.As part of a partnership with the local authority, the IATUS project aims to measure the impact ofthese changes on thermal comfort. The originality of this work consisted in combiningmeasurements with a comfort measurement station to measure UTCI with surface infrared mappingcarried out by drone. For cost reasons, the infrared camera used (Flir Vue pro) could not be used toacquire temperatures, but only to obtain numerical values proportional to surface temperatures. Inorder to calculate surface temperatures, we designed a characterization protocol using large groundtargets whose thermal properties were measured in laboratory. We studied two methods ofevaluating surface temperatures (linear vs Planck's law). Two field campaigns took place in thecourtyard: 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 themicroclimates that drive thermal comfort.We were able to show that it was possible to estimate thermal comfort on a hot day and make thelink with surface temperatures at low cost. Moreover, results show the positive impact of theredevelopment, in particular an improvement in comfort towards the vegetated areas