Geology Reference
In-Depth Information
Conduction
(or heat conduction, as implied here) The transfer of internal energy from a medium or
region of higher temperature to a medium or region of lower temperature from particle
to particle.
Convection
The transfer of heat through a fluid (liquid or gas) caused by molecular motion.
Digital number
Abbreviated as DN, refers to the digital value assigned to a pixel (smallest element) in
a digital image. The DN value often represents a physical property, for example, in an
optical image it represents the brightness value (related to amount of energy reflected).
Electromagnetic energy A dynamic form of energy that is caused by the oscillation or acceleration of a charged
particle. All substances above absolute zero (0 K or
-
273.16°C) emit a range of
electromagnetic energy.
Electromagnetic
spectrum
The entire range of electromagnetic energy. It stretches from short-wavelength gamma
rays to long-wavelength radio waves.
Emission spectra
The amount of energy emitted by an object at a given temperature as a function of
wavelength. Emission spectra are often shown for an ideal blackbody and are gov-
erned by Plank
'
s law.
Fire depth
The vertical distance between the land surface and the center of the underground
burning source (coal fire in this case).
Full Width Half Max
The total width of a temperature profile (or a modeled curve fit, e.g., Lorenzian fit) at
half the difference between maximum and minimum recorded temperatures.
Geoenvironmental
indicators
Qualitative or quantitative records of features, areas, or phenomena of significance on
the Earth
'
s surface or its surrounding environment.
Geographic Information
System
Science and technology involved in acquiring, integrating, analyzing, managing, and
visualizing geospatial data and information.
Greenhouse gas
A gas in the atmosphere that significantly absorbs and emits radiations in the thermal
infrared region of the electromagnetic spectrum.
Heat source
In the current context, the subsurface coal fires that are causing ground heating and
surface cracking.
Hyperspectral remote
sensing
Also increasingly referred to as imaging spectroscopy. It is a form of remote sensing
where data is acquired in several narrow, and often near contiguous, spectral channels
or spectral bands.
'
Interferometric Synthetic
Aperture Radar (InSAR)
InSAR is a technique for extracting three-dimensional information of the Earth
s
surface by using the phase content of the radar signal as an additional information
source derived from the complex radar data.
Kinetic temperature
The actual temperature of a body as measured with a contact thermometer.
Land-cover mapping
In the current context it implies the use of remote sensing data to map the spatial
distribution of the varied physical material on the surface of the Earth.
Multispectral remote
sensing
Remote sensing in several discrete spectral wavelengths. For example, data from the
Landsat satellite is considered multispectral.
Near infrared
Region of the electromagnetic spectrum where the radiations have wavelengths from
just longer than the visible (about 0.7
μ
m) to about 1.3
μ
m.
Near-infrared plateau
The continuous high reflectance from green vegetation in the near-infrared region.
This plateau helps to discriminate vegetation type and vegetation health.
