I had similar research on LST versus distance for Landfills. I wanted to know how LST changes along with the distance from the landfills. For this purpose, I used euclidean distance in Arcgis and assigned a raster map for an area. Once it is extracted, I combined the results with LST and extracted the multi values to points, once it is clarified, I had an attribute table which included LST and distances in two different columns. Therefore, you can extract the attribute table as dbase file and import it into an excel sheet.
You can use buffer analysis of that. Take a middle point in the city and then create fine equal buffer inter and then calculated the mean LST and of each buffer and the plot the distance on X-axis and mean LST on the y-axis.