A B C
D E F
G H I
J K L
M N O
P R S
T U V
W Y Z
Words begining with "I"
A thick mass of ice extending from a polar shore. The seaward edge
is afloat and sometimes extending hundreds of miles into the sea.
Instantaneous Field of View. See Multispectral
Scanner for sample usage.
See International Geophysical Year
Pictorial representation of data acquired by satellite systems,
such as direct readout
images from environmental satellites. An image is not a photograph.
An image is composed of two-dimensional grids of individual picture
elements (pixels). Each pixel has a numeric value that corresponds to
the radiance or temperature of the specific ground area it depicts.
The area represented by each pixel of a satellite image. The
smaller the area represented by a pixel, the more accurate and
detailed the image. For example, if a U.S. map and a world map are
printed on identically sized sheets of paper, one square inch on the
U.S. map will represent far less area and provide for more detail
than one square inch on the world map. In this example the U.S. map
has higher resolution. APT has a
resolution of 4 km, HRPT has a
resolution of 1.1 km and WEFFAX
resolution is 8 km.
A satellite instrument that measures and maps the Earth and its
atmosphere. Imager data are converted by computer into pictures.
Inclination (aka i)
One of the six Keplerian
elements, it indicates the angle of the orbit plane to the
central body's equator.
The elliptical path of a satellite orbit lies in a plane known as
the orbital plane. The orbital plane always goes through the center
of the Earth but may be tilted at any angle relative to the equator.
Inclination is the angle between the equatorial plane and the orbital
plane measured counter-clockwise at the ascendinq node.
A satellite in an orbit that exactly matches the equator has an
inclination of 0 degrees, whereas one whose orbit crosses the Earth's
poles has an inclination of 90 degrees. Because the angle is measured
in a counterclockwise direction, it is quite possible for a satellite
to have an inclination of more than 90 degrees. An inclination of 180
degrees would mean the satellite is orbiting the equator, but in the
opposite direction of the Earth's rotation. Some sun-synchronous
satellites that maintain the same ground track throughout the year
have inclinations of as much as 98 degrees. U.S. scientific
satellites that study the sun are placed in orbits closer to the
equator, frequently at 28 degrees inclination. Most weather
satellites are placed in high-inclination orbits so they can oversee
weather conditions world-wide. See orbital
All of the means and mechanisms for data receipt, processing,
storage, retrieval, and analysis. Information systems can be designed
for storage and dissemination of a variety of data products -
including primary data sets and both intermediate and final analyses
- and for an interface providing connections to external computers,
external data banks, and system users. To be effective, the design
and operation of an information system must be carried out in close
association with the primary producers of the data sets, as well as
other groups producing integrated analyses or intermediate products.
Infrared radiation (IR)
Infrared is electromagnetic radiahon whose wavelength spans the
region from about 0.7 to 1000 micrometers (longer than visible
radiation, shorter than microwave radiation). Remote-sensing
instruments work by sensing radiation that is naturally emitted or
reflected by the Earth's surface or from the atmosphere, or by
sensing signals transmitted from a satellite and reflected back to
it. In the visible and near-infrared regions, surface chemical
composition, vegetation cover, and biological properties of surface
matter can be measured. In the mid-infrared region, geological
formations can be detected due to the absorption properties related
to the structure of silicates. In the far infrared, emissions from
the Earth's atmosphere and surface offer information about
atmospheric and surface temperatures and water vapor and other trace
constituents in the atmosphere.
Since IR data are based on temperatures rather than visible
radiation, the data may be obtained day or night.
Indian National Satellite.
Latin for "in original place." Refers to measurements made at the
actual location of the object or material measured. Compare with
Solar radiation incident upon a unit horizontal surface on or
above the Earth's surface.
Instantaneous Field of View (IFOV)
The field of view of a scanning detector system at a given
instant. The range of angles scanned by the system is then called the
field of view, or swath
Integrated Circuit (lC)
A solid state electronic circuit that consists of several
micro-components constructed to perform a special function.
International Date Line
An imaginary line of longitude 180 degrees east or west of the
An internationally agreed-upon naming convention for satellites.
The designator contains the last two digits of the launch year, the
launch number of the year, and the part of the launch, i.e., "A"
indicates payload, "B" the rocket booster, or second payload, etc.
International Geophysical Year (IGY)
(1957-58) The IGY was organized by the scientific community
through the International Council of Scientific Unions (ICSU) . It
was highlighted by international cooperation in the exploration of
world-wide geophysical phenomena and by the inauguration of the space
age through the launching of the first satellites (USSR's Sputnik I
and US Explorer I ) to study the upper atmosphere and Earth's nearby
International Space Year (ISY)
(1992) Designated the first international celebration of
humanity's future in the space age. Themes included the global
perspective of the space age, discovery, exploration, and scientific
inquiry. An important ISY scientific focus was Mission
to Planet Earth. A wide range of educational programs and public
events emphasized ISY's global perspective. 1992 also commemorated
the 500th anniversary of Columbus' voyage to the New World and the
35th anniversary of the International Geophysical
International System of Units (SI)
The International System of Units prescribes the symbols and
prefixes shown in the table to form decimal multiples and
submultiples of Sl units.
Factor Prefix Symbol
10 deka da
100 hecto h
1,000 kilo k
1,000,000 mega M
1,000,000,000 giga G
1,000,000,000,000 tera T
1,000,000,000,000,000 peta P
.1 deci d
.01 centi c
.001 milli m
.000,001 micro u
.000,000,001 nano n
.000,000,000,001 pico p
.000,000,000,000,001 femto f
.000,000,000,000,000,001 atto a
The following examples illustrate the use of these prefixes.
0.000,001 meters = 1 micrometer = l um
1000 meters = 1 kilometer = 1 km
1,000,000 cycles per second = 1 meqahertz = 1 MHz
Atom or molecule that has acquired an electric charge by the
loss/gain of one or more electrons.
Inches per second.
Lines drawn on a weather map joining places of equal barometric
Of or indicatinq equality of temperature.
Lines connecting points of equal temperature on a weather map.
Narrow strip of land located between two bodies of water,
connectinq two larqer land areas.
ITOS (Improved TIROS Operational Satellite)
Second generation, polar-orbiting, environmental satellites
utilized to augment NOAA's world-wide weather observation
capabilities. ITOS were launched from 1970-1976, but eventually
replaced by the third generation of polar-orbiting, environmental
satellites TIROS-N (first launched in 19781. See TIROS.
A B C
D E F
G H I
J K L
M N O
P R S
T U V
W Y Z