In recent years, the issue of improving the spatial resolution of thermal images in urban areas has been introduced as a new challenge. The purpose of this study is to use the impervious surfaces indices and vegetation indices to improve the spatial resolution of Landsat ETM + thermal band over Tehran ...
Read More
In recent years, the issue of improving the spatial resolution of thermal images in urban areas has been introduced as a new challenge. The purpose of this study is to use the impervious surfaces indices and vegetation indices to improve the spatial resolution of Landsat ETM + thermal band over Tehran as a part of the study area. After the initial pre-processing, images obtained using the mean filter was simulated at spatial resolutions 120, 240, 480, 720 and 960 m. The relationships between these simulated imaged with the image simulated at the resolution of 960 m were calculated by the use of regression models.These derived models, containing vegetation and impervious surface indices, were then used to simulation of surface temperatures in different pixel sizes. The accuracy of each output, has been evaluated using the thermal images of ETM + and MODIS sensors.The results showed that by increasing the spatial resolution, the errors increases while the gradient of error is not fixed. So that in all indices, there are more increasing in gradient of error when the pixel size goes to smaller than 240 meters.Moreover, the best performance was obtained by combination of impervious surfaces indices and vegetation indices due to the enhancement of spatial resolution of thermal images in Tehran city.Using the combination of these indices, the spatial resolution of the MODIS sensor can be reached to about 240 meters, while the absolute error value is less than 1 K Kelvin.
