Airborne thermal remote sensing: the case of the city of Olomouc, Czech Republic

This paper describes the process of very high-resolution thermal mosaic acquisition using low-altitude airborne remote sensing and the basic analysis of data regarding urban climate research. The process of data acquisition from flight planning to final mosaicking is described. A broadband thermal camera was mounted to a Cessna aeroplane for two flights over the city; one performed in the morning and one in the afternoon. The ground resolution of the final mosaic fluctuates between 90 and 105 cm. Gathered data had to be processed to acquire kinetic temperature values. The processing consisted of radiometric, geometric, atmospheric and emissivity corrections. As a result, two mosaics covering the city were created. The difference between the building canopy layer and ground level was investigated, and a 5 degrees C increase was found during the day on the rooftop level. It was confirmed that natural materials do not heat as much as artificial ones. Local Climate Zones were used in the analysis as the spatial unit for comparison of the thermal regime at the neighbourhood level. To summarise, the possibilities of extreme resolution thermal remote sensing data acquisition and analysis are demonstrated.