chapter 8 part 2 Flashcards
Water, rocks, soil, vegetation, the atmosphere, and human tissue all have the ability to conduct heat directly through them _________________
thermal conductivity
ability to store heat
thermal capacity
some materials respond to changes in temp more rapidly or slowly than others
thermal inertia
Thermal conductivity
(K) the rate that heat will pass through a material and is measured as the number of calories that will pass through a 1-cm cube of material in 1 second when two oppposite faces are maintained at 1 C in temp
Thermal inertia
(P) measurement of the thermal response of a material to temperature changes, measured in calories per square centimeter per second square centimeter per second square root per degree celsius
relationship between thermal intertia and density
thermal inertia generally increases linearly with increasing material density
diurnal cycle
at sunrise earth begins intercepting mainly short wavelength energy (.4 - .7 um) from the sun. From about 6:00 am to 8:00 pm the terrain intercepts the incoming short wavelength energy and reflects much of it back into the atmosphere where we can use optical remote sensors to measure the reflected energy. Some of the incident short wavelength energy is absorbed by the terrain and re-radiated back in the atmosphere as thermal infrared long wavelength radiation (3-14). Outgoing radiation reaches its peak when surface temp is the hottest around 4 pm–so there is a lag between peak incoming short wavelength radiation and outgoing long wavelength radiation. outgoing lonwave continues all night.
crossover period
after sunrise and near sunset when some materials have the same radiant temperature (not wise to remotely sense this)
formula for diameter of circular ground area view by the remote sensor
diameter = IFOV x altitude of scanner
thermal infrared detectors composed of:
indium antimonide (peak sensitivity at 5um
mercury doped-germanium (peak sensitivity at 10um)
mercury-cadmium-telluride (sensitive from 8-14um
there is an _______ relationship between having high spacial resolution and high radiometric resolution when collecting thermal infrared data
inverse….. the larger the radiometer IFOV, the longer the dwell time, so the better the radiometric resolution, but the poorer poorer the spacial resolution
signal to noise
good signal to noise ration means the radiant energy signal measured is much stronger than any noise introduced from the sensor system components
ground width swath
length of the terrain strip remotely sensed by the system during one compete across-track sweep of the scanning mirror
inverse square law
the intensity of radiation emitted from a point source varies as the inverse square of the distance between the source and receiver
Landsat thematic mapper 4 and 5
launched in ‘82 and ‘84, 120 x 120m thermal infrared data (10.4 - 12.5 um) along with two bands of middle infrared data
