Surface temperatures of the Paris basin during summertime, using satellite remote sensing data.

The surface temperatures of the Paris basin in August 1998 were analyzed using a series of twenty two, thermal infrared images from the NOAA–AVHRR satellites, at 1km resolution; a multi-spectral image from SPOT-HRV satellite, at 20 m resolution; and in-situ data from the ESQUIF experiment. The method was based on the construction of statistical thermal infrared images, of a land cover classification image, and on their combination using a Geographic Information System. The statistical thermal infrared images revealed large spatial and temporal variations of surface temperatures. Those images displayed a significant contrast between a welldefined central heat-island at night, related to the built density and lack of vegetation, and many distinct microclimates during the day, related to surface properties. The strong negative correlation between the diurnal land surface temperature amplitude and the fractional vegetation index, confirmed the cooling effect of urban parks and suburban forests. The images combination of statistical temperatures and land cover classification improved the accuracy of data interpretation, given the urban surfaces heterogeneity.