The KT-19 Skin Surface Temperature Sensor (KSSTS) is a radiometer that measures the brightness temperature of the surface beneath an aircraft. By knowing the emissivity of the target—sea ice has an emissivity very close to one—the KT-19 can estimate the surface temperature. Thick sea ice is sometimes as cold as -20° or -30° Celsius (-4° or -22° Fahrenheit) while open water is around -2° Celsius (28° Fahrenheit). The KT-19 as calibrated for NASA’s IceBridge mission can accurately measure the temperature of sea ice leads larger than 40 meters (130 feet). For larger leads covered in thin ice, the KT-19 can provide surface temperature data that can be used to estimate ice thickness. Leads smaller than 40 meters have a reduced effect due to the KT-19 footprint, and correspondingly the KT-19 measures a colder signal for those leads, but many small leads can still be detected.
