Glossary: S

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  1. A nominal frequency range from 4 to 2 GHz (7 to 20 cm wavelength) within the microwave (radar) portion of the electromagnetic spectrum. S-band radars are used for medium-range meteorological applications, for example rainfall measurements, as well...
  2. The degree of salt in water. The rise in sea level due to global warming would result in increased salinity of rivers, bays and aquifers. This would affect drinking water, agriculture and wildlife. Source: NASA (http://earthobservatory.nasa.gov/...
  3. The process of obtaining a sequence of discrete digital values from a continuous sequence of analog data. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  4. A free-flying object that orbits the Earth, another planet, or the sun. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  5. In telecommunications, the use of artificial satellites to provide communication links between various points on Earth.(source: Encyclopedia Britannica) Satellite communications play a vital role in the global telecommunications system....
  6. The time from one perigee (the point of an elliptical orbit path where a satellite is closest to Earth) to the next. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  7. An imaging system consisting of lenses, moving mirrors, and solid-state image sensors used to obtain observations of the Earth and its atmosphere. Scanning radiometers, which are the sole imaging systems on all current operational weather satellites...
  8. The process by which electromagnetic radiation interacts with and is redirected by the molecules of the atmosphere, ocean, or land surface. The term is frequently applied to the interaction of the atmosphere on sunlight, which causes the sky to...
  9. A high-frequency radar instrument that transmits pulses of energy towards the ocean and measures the backscatter from the ocean surface. It detects wind speed and direction over the oceans by analyzing the backscatter from the small wind-induced...
  10. Object space illuminated by a sensor. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  11. The height of sea ice from the keel (the lowest point underwater) to the ridge (the highest point above water). http://earthobservatory.nasa.gov/Features/ClimateClues/Images/diagram.gi... Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  12. The datum against which land elevation and sea depth are measured. Mean sea level is the average of high and low tides. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  13. The temperature of the layer of seawater (approximately 0.5 m deep) nearest the atmosphere. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  14. The excess radiative energy that has passed from the Earth's surface to the atmosphere through advection, conduction, and convection processes. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  15. Device that produces an output (usually electrical) in response to stimulus such as incident radiation. Sensors aboard satellites obtain information about features and objects on Earth by detecting radiation reflected or emitted in different bands...
  16. The relationship between input and output for a given measurement. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  17. The radiation received from the sun and emitted in the spectral wavelengths less than 4 microns. It is also called 'solar radiation'. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  18. Energy received from the sun is solar radiation. The energy comes in many forms, such as visible light (that which we can see with our eyes). Other forms of radiation include radio waves, heat (infrared), ultraviolet waves, and x-rays. These forms...
  19. A special kind of radiometer that measures changes in atmospheric temperature with height, as well as the content of various chemical species in the atmosphere at various levels. The High Resolution Infrared Radiation Sounder (HIRS), found on NOAA...
  20. The set of agencies, organizations and institutions at local, national, regional and international levels that focus their activities on the design, launch, deployment and operation of satellites, space-stations and probes.
  21. Information that is derived from the data which is collected through sensors in satellites When we talk about space-based information, we refer to the information that can be derived using Earth Observation, GNSS and satellite communications.
  22. A characteristic that refers to a location (which may be a specific location on the Earth's surface, or relative to an arbitrary point). Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  23. A finite segment of wavelengths in the electromagnetic spectrum. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  24. This refers to the particular form or shape evinced by the power spectrum calculated from the data comprising the time series of a process. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  25. A device for measuring the relative amounts of radiant energy or radiant flux as a function of wavelength. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  26. 1. The series of colored bands diffracted and arranged in the order of their respective wave lengths by the passage of white light through a prism or other diffracting medium and shading continuously from red (produced by the longest visible wave)...
  27. Region of the atmosphere between the troposphere and mesosphere, having a lower boundary of approximately 8 km at the poles to 15 km at the equator and an upper boundary of approximately 50 km. Depending upon latitude and season, the temperature in...
  28. Point where a straight line drawn from a satellite to the center of the Earth intersects the Earth's surface. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  29. Describes the orbit of a satellite that provides consistent lighting of the Earth-scan view. The satellite passes the equator and each latitude at the same time each day. For example, a satellite's sun-synchronous orbit might cross the equator...
  30. The temperature of the air near the surface of the Earth, usually determined by a thermometer in an instrument shelter about 2 m above the ground. The true daily mean, obtained from a thermograph, is approximated by the mean of 24 hourly readings...
  31. The area observed by a satellite as it orbits the Earth. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  32. The ability to see large areas at the same time. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  33. A high-resolution ground-mapping technique that effectively synthesizes a large receiving antenna by processing the phase of the reflected radar return. The along-track resolution is obtained by timing the radar return (time-gating) as for ordinary...