Remote sensing is key to understanding the Urban Heat island effect. Detecting thermal properties of the various surfaces is a common way to study UHI.  Many satellites carry remote sensors with the capability of retrieving information about the temperatures of varying surfaces.  They do this by sensing differing amounts of reflectivity in the thermal infrared portion of the electromagnetic spectrum.  Sensors that can collect this data include LANDSAT and MODIS.  In addition to temperature data, information on the proportion of vegetated surfaces and impervious surfaces is also important, and can also be collected using the LANDSAT satellite.  More in depth information about how remote sensing is used in research, and information on the different remote sensors used, can be found under the Additional information tab.