Observation of Urban Heat Island using Airborne Thermal Sensors

As a basic study on urban heat island, the surface temperature of the central Tokyo, Japan is investigated using images obtained by airborne thermal sensors. Thermographies were taken from a helicopter on August 7, 2007, both in the daytime and at night. Using these thermal images, the variation of surface temperature can be observed in a detailed manner. Although the road surface and building roofs shows very high temperature, vegetation and water bodies show much lower temperature. The temperature at night also shows significant variation depending on the surface material and the sunlight condition in the daytime. Ground based verification of surface temperature was also carried out using a handheld thermal sensor. Based on these observations, detailed variations of temperature on various urban earth surfaces were revealed.