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Words begining with "C"
Calibration
Act of comparing an instrument's measuring accuracy to a known
standard.
Calorie
The amount of heat needed to raise the temperature of one gram of
water at 15 degrees centigrade one degree centigrade. Compare with
British Thermal Unit.
Canal
A man-made watercourse designed to carry qoods or water.
Canopy
The layer formed naturally by the leaves and branches of trees and
plants.
Canyon
A large but narrow gorge with deep sides.
Cape (or Point)
A piece of land extendinq into water.
Carbon Cycle
All parts (reservoirs) and fluxes of carbon. The cycle is usually
thought of as four main reservoirs of carbon interconnected by
pathways of exchange. The reservoirs are the atmosphere, terrestrial
biosphere (usually includes freshwater systems), oceans, and
sediments (includes fossil fuels). The annual movements of carbon,
the carbon exchanges between reservoirs, occur because of various
chemical, physical, geological, and biological processes. The ocean
contains the largest pool of carbon near the surface of the Earth,
but most of that pool is not involved with rapid exchange with the
atmosphere.
Carbon Dioxide (CO2)
A minor but very important component of the atmosphere, carbon
dioxide traps infrared radiation. Atmospheric CO2 has increased about
25 percent since the early 1800s, with an estimated increase of 10
percent since 1958 (burning fossil fuels is the leading cause of
increased CO2, deforestation the second major cause). The increased
amounts of CO2 in the atmosphere enhance the greenhouse effect,
blocking heat from escaping into space and contributing to the
warming of Earth's lower atmosphere.
Carrier
Radio frequency capable of being modulated with some type of
information. See modulation.
Carrying Capacity
The steady-state density of a given species that a particular
habitat can support.
Catalog Number
A five-digit number assigned to a cataloged orbiting object. This
number may be found in the NASA Satellite Situation Report and on the
NASA Prediction Bulletins.
Cathode Ray Tube (CRT)
A television picture tube for image display.
Centigrade
Temperature scale proposed by Swedish astronomer Anders Celsius in
1742. A mixture of ice and water is zero on the scale; boiling water
is designated as 100 degrees. A degree is defined as one hundredth of
the difference between the two reference points, resulting in the
term centigrade (100th part).
To convert centigrade to Fahrenheit
multiply the centigrade temperature by 1.8 and add 32.
F = 9/5 C + 32
To convert Fahrenheit to
centigrade: subtract 32 from the Fahrenheit temperature and divide
the quantity by 1.8.
C = (F -32) / 1.8.
Central Processing Unit (CPU)
Main part of a computer consisting of an arithmetic logic unit and
a control unit. See microprocessor.
Chlorofluorocarbon (CFC)
A family of compounds of chlorine, fluorine, and carbon, entirely
of industrial origin. CFCs include refrigerants, propellants for
spray cans {this usage is banned in the U.S., although some other
countries permit it) and for blowing plastic-foam insulation,
styrofoam packaging, and solvents for cleaning electronic circuit
boards. The compounds' lifetimes vary over a wide ranae, exceedinq
100 years in some cases.
CFCs' ability to destroy stratophpeic ozone through catalytic
cycles is contributing to the depletion of ozone worldwide. Because
CFCs are such stable molecules, they do not react easily with other
chemicals in the lower atmosphere. One of the few forces that can
break up CFC molecules is ultraviolet radiation, however the ozone
layer protects the CFCs from ultraviolet radiation in the lower
atmosphere. CFC molecules are then able to migrate intact into the
stratosphere, where the molecules are bombarded by ultraviolet rays,
causing the CFCs to break up and release their chlorine atoms. The
released chlorine atoms participate in ozone destruction, with a
single atom of chlorine able to destroy ozone molecules over and over
again.
International attention to CFCs resulted in a meeting of diplomats
from around the world in Montreal in 1987. They forged a treaty that
called for drastic reductions in the production of CFCs. In 1990,
diplomats met in London and voted to significantly strengthen the
Montreal Protocol by calling for a complete elimination of CFCs by
the year 2000. See Montreal
Protocal.
Circadian Rhythm
The cyclical changes in physiological processes and functions that
are related to the 24-hour diurnal
cycle.
Circuit
The complete path of an electric current; an assemblage of
electronic elements; a means of two-way communication between two
points - comprised of associated "go" and "return" channels.
Circular Polarized RF
Radio frequency transmissions where the wave energy is divided
equally between a vertically and a horizontally-polarized component.
Clarke Belt
A belt 22,245 miles (35,800 kilometers) directly above the equator
where a satellite orbits the Earth at the same speed the Earth is
rotating. Science fiction writer and scientist Arthur C. Clarke wrote
about this belt in 1945, hence the name.
Climate
The average weather conditions in an area determined over a period
of years.
Climatology
Science dealing with climate and climate phenomena.
Clone
A person or thing very much like another, e.g., a copy of another
manufacturer's computer.
Cloudburst
Any sudden, heavy rain shower.
Clouds
A visible mass of water vapor suspended in the atmosphere above
Earths surface. Clouds form in areas where air rises and cools. The
condensing water vapor forms small droplets of water (0.012 mm) that,
when combined with billions of other droplets, form clouds. Clouds
can form along warm and cold fronts, where air flows up the side of
the mountain and cools as it rises higher into the atmosphere, and
when warm air blows over a colder surface, such as a cool body of
water.
Clouds fall into two general categories: sheetlike or
layer-looking stratus clouds (stratus means layer) and cumulus clouds
{cumulus means piled up). These two cloud types are divided into four
more groups that describe the clouds altitude
High clouds form above 20,000 feet in the cold region of the
troposphere, and are denoted by the prefix CIRRO or CIRRUS. At this
altitude water almost always freezes so clouds are composed of ice
crystals. The clouds tend to be wispy, are often transparent, and
include cirrus, cirrocumulus, and cirrostratus.
Middle clouds form between 6,500 and 20,000 feet and are denoted
by the prefix ALTO. They are made of water droplets and include
altostratus and altocumulus
Low clouds are found up to 6,500 feet and include the
stratocumulus and nimbostratus clouds. When stratus clouds contact
the ground they are called fog.
Vertical clouds, such as cumulus, rise far above their bases and
can form at many heights. Cumulonimbus clouds, or thunderheads, can
start near the ground and soar up to 75.000 feet.
Cloud Streets
Lines or rows of cumuliform clouds.
Coastal Zone Color Scanner (CZCS)
The first spacecraft instrument devoted to measurement of ocean
color. Although instruments on other satellites have sensed ocean
color, their spectral bands, spatial resolution, and dynamic range
were optimized for geographical or meteorological use. In the CZCS,
every parameter is optimized for use over water to the exclusion of
any other type of sensing. The CZCS flew on the Nimbus-7 spacecraft.
Coaxial Cable
A hollow copper cylinder, or other cylindrical conductor,
surrounding a single-wire conductor having a common axis (hence
coaxial). The space between the cylindrical shell and the inner
conductor is filled with an insulator which may be plastic or mostly
air, with supports separating the shell and the inner conductor every
inch or so. The cable is used to carry radio frequency signals to or
from antennas, etc.
Comma Cloud
Band of organized cumuliform clouds that look like a comma from a
satellites perspective. Comma clouds are indicators of heavy storms.
Common Business Oriented Language (COBOL)
A computer programming language written for business application.
Compact Disk-Read Only Memory (CD-ROM)
Type of computer memory that reads and uses information, but does
not allow information to be added, changed, or erased. Digital
information is read by laser. CD-ROM does not depend upon any
proprietary hardware or software, making it an accessible vehicle for
electronic publishing.
Computer
Electronic machine capable of performing calculations and other
manipulations of various types of data, under the control of a stored
set of instructions. The machine itself is the hardware; the
instructions are the program or software. Depending upon size,
computers are called mainframes, minicomputers, and microcomputers.
Microcomputers include desk-top and portable personal computers.
Condensation
Change of a substance to a denser form, such as gas to a liquid.
The opposite of evaporation.
Conduction
The transfer of heat from one substance to another by direct
contact. Denser substances are better conductors; the transfer is
always from warmer to colder substances.
Contrails
Condensation trails. Artificial clouds made by the exhaust of jet
aircraft.
Convection
The rising of warm air and the sinking of cool air. Heat mixes and
moves air. When a layer of air receives enough heat from the Earth's
surface, it expands and moves upward. Colder, heavier air flows under
it which is then warmed, expands, and rises. The warm rising air
cools as it reaches higher, cooler regions of the atmosphere and
begins to sink. Convection causes local breezes, winds, and
thunderstorms.
Coordinated Universal Time (UTC)
(aka Greenwich Mean Time [GMT]) Local time at zero degrees
longitude at the Greenwich Observatory, England. UTC uses a 24-hour
clock, i.e., 2:00 a.m. is 0200 hours, 2:00 p.m. is 1400 hours,
midnight is 2400 or 0000 hundred hours.
Continent
One of the large, continuous areas of the Earth into which the
land surface is divided. The six geographically defined continents
are politically defined as seven:
- Africa
- Asia
- Australia
- Europe
- North America
- South America
- Antarctica
Coriolis Force
The apparent tendency of a freely moving particle to swing to one
side when its motion is referred to a set of axes that is itself
rotating in space, such as Earth. The acceleration is perpendicular
to the direction of the speed of the article relative to the Earth's
surface and is directed to the right in the northern hemisphere.
Winds are affected by rotation of the Earth so that instead of a wind
blowing in the direction it starts, it turns to the right of that
direction in the northern hemisphere; left in the southern
hemisphere.
Coupled System
Two or more processes that affect one another.
Crop Calendar
The schedule of the maturing and harvesting of seasonal crops.
Cryosphere
One of the interrelated components of the Earths system, the
cryosphere is frozen water in the form of snow, permanently frozen
ground (permafrost), floating ice, and glaciers. Fluctuations in the
volume of the cryosphere cause changes in ocean sea-level, which
directly impact the atmosphere and biosphere.
Culmination
The point at which a satellite reaches its highest position or
elevation in the sky, relative to an observer (aka the closest point
of approach).
Cyclone
An area of low pressure where winds blow counterclockwise in the
Northern Hemisphere and clockwise in the Southern Hemisphere. See
anticyclone, wind.
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