– A group of smaller elements that form a complete unit.
Ecosystem – An interacting system of plants,
animals, fungi, and microorganisms, and their environment.
Electromagnetic radiation – Another term
for light. Light travels in waves of various frequencies; only a
small range of frequencies makes up visible light.
spectrum – The full range of frequencies, from
radio waves to gamma waves, that characterizes light.
Gamma rays – The highest-energy, shortest-wavelength
Global climate change – Alteration of temperature
and precipitation patterns throughout the world.
Infrared radiation – Electromagnetic radiation
with longer wavelengths than the visible light but shorter wavelengths
Mesoscale – Phenomena approximately 10 to
100 kilometers (6 – 60 miles) or more in horizontal extent.
NDVI – See Normalized-Difference Vegetation
Near-polar – A satellite orbit with an orbital
plane within 10 degrees of a plane containing true North or true
Vegetation Index – An estimate of the greenness
of vegetation calculated from visible and infrared satellite measurements.
Pixel – An abbreviation of picture element.
The minimum-size area on the ground detectable by a remote sensing
device such as a satellite. The size varies depending on the type
Radio waves – Electromagnetic radiation
with the longest wavelength.
Radiometer – A device used for detecting
and measuring radiation.
Signature – When solar radiation hits a
surface, it may be transmitted, absorbed or reflected. Different
materials reflect and absorb differently at different wavelengths.
The greater the amount of radiation absorbed the warmer the surface.
The recording of these different wavelengths by the sensor onboard
the satellite is referred to as a spectral signature.
Sun-synchronous – A satellite orbit such
that the satellite passes the equator and each latitude at the same
time each day. The orbital plane of a sun-synchronous orbit must
also process (rotate) approximately one degree each day, eastward,
to keep pace with the Earth's revolution around the sun.
Topographic – Showing the relief of the
Ultraviolet radiation – Electromagnetic
radiation with a shorter wavelengths than visible light but longer
wavelengths than x-rays.
Visible light – Light that can be seen by
the human eye.