APPENDIX I
GLOSSARY
A
AFWA—Air Force Weather Agency.
ALBEDO—The percent of radiation returning from a
surface compared to that which strikes it. An
arbitrary value of whiteness possessed by a digital
image or an individual pixel.
ALGORITHM—A step-by-step procedure for
solving a mathematical problem.
ANALOG—Proportional and continuous. Analog
data is collected or presented in continuous form,
such as voltage measurements or temperature
changes.
ANOMALOUS PROPAGATION (AP)—The
abnormal bending of a radar beam as it passes
through the atmosphere.
ANOMALY—Deviation or departure from the
normal. Irregular.
APOGEE—The highest point (greatest distance from
the surface) of a satellite orbit.
APT—Automatic Picture Transmission. The
automatic transmission of images by polar-
orbiting satellites.
ASCENDING NODE—The period of time when a
polar-orbiting satellite is traveling from south
toward the north.
ASSOCIATED PRINCIPAL USER—A principal
user linked to a WSR-88D system with a dedicated
telecommunication line.
ATTENUATION—Any process in which the power
of a beam of energy is dissipated.
AUTODIN—Automatic Digital Network.
AVHRR—Advanced
Very
High
Resolution
Radiometer.
AWN—Automated Weather Network-the complex
worldwide collection and distribution network of
meteorological data operated by the Air Force.
AZIMUTH— The horizontal angular measurement
from a fixed reference to a point. The Navy uses
angular measurements in clockwise degrees from
0 to 360. When 0 is referenced to true north, the
result is a true azimuth bearing. When referenced
to an arbitrary direction, such as the bow of a ship,
the result is a relative azimuth bearing.
B
BACKING—A change in wind direction in a
counterclockwise manner in the Northern
Hemisphere, or a clockwise direction in the
Southern Hemisphere.
BACKSCATTER— That portion of energy scattered
back from a target to a radar antenna.
BASE DATA—Digital fields of reflectivity, mean
radial velocity, and spectrum width data provided
at the finest resolution available from the WSR-
88D Doppler radar.
BEAM WIDTH—The angular width of the antenna
pattern. Usually the width where the power
density is one-half that on the axis of the beam.
(half-power point).
BOUNDED WEAK ECHO REGION (BWER)—A
core of weak equivalent reflectivity in a
thunderstorm that identifies the location of a
strong updraft.
BRIGHT BAND—The enhanced layer of a radar echo
caused by the difference in radar reflectivity of ice
and water particles. This echo is interpreted as the
delineation on a radar display between frozen and
liquid precipitation.
C
CENTROID—The center of mass of a storm.
CNMOC—Commander, Naval Meteorology and
Oceanography Command. Headquartered at
Stennis Space Center, Mississippi.
CONUS—Conterminous/continental United States.
Those states of the United States enclosed
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