Glossary: R

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  1. R&D
    Research and Development. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  2. The study of interference patterns caused by radar signals; a technique that enables scientists to generate three dimensional images of the Earth's surface. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  3. 1. In optics, the point or object from which light proceeds. 2. In geometry, a straight line proceeding from a given point, or fixed pole, about which it is conceived to revolve. 3. In astronomy, the point in the heavens from which a shower of...
  4. Energy transfer in the form of electromagnetic waves or particles that release energy when absorbed by an object. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  5. A change in the balance between incoming solar radiation and outgoing infra-red radiation. Without any radiative forcing, solar radiation coming to the Earth would continue to be approximately equal to the infra-red radiation emitted from the Earth...
  6. Theory dealing with the propagation of electromagnetic radiation through a medium. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  7. The complete range of frequencies or wave lengths of electromagnetic waves, specifically those used in radio and television. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  8. An electrical impulse sent through the atmosphere at radio frequency. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  9. Giving off or capable of giving off radiant energy in the form of particles or rays, as in alpha, beta, and gamma rays. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  10. An instrument that quantitatively measures electromagnetic radiation. Weather satellites carry radiometers to measure radiation from snow, ice, clouds, bodies of water, the Earth's surface, and the sun. Source: NASA (http://earthobservatory.nasa.gov...
  11. A balloon-borne instrument that measures meteorological parameters from the Earth's surface up to 20 miles in the atmosphere. The radiosonde measures temperature, pressure, and humidity, and transmits or 'radios' these data back to Earth. Upper air...
  12. An evergreen woodland of the tropics distinguished by a continuous leaf canopy and an average rainfall of about 100 inches per year. Rain forests play an important role in the global environment. The Earth sustains life because of critical balances...
  13. Calibrated container that measures the amount of rainfall during a specific period of time. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  14. As it happens. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  15. Actions taken to reestablish a community after a period of rehabilitation subsequent to a disaster. Actions would include construction of permanent housing, full restoration of all services, and complete resumption of the pre-disaster state.
  16. The restoration, and improvement where appropriate, of facilities, livelihoods and living conditions of disaster-affected communities, including efforts to reduce disaster risk factors. The recovery phase begins soon after the response and...
  17. The return of light or sound waves from a surface. If a reflecting surface is plane, the angle of reflection of a light ray is the same as the angle of incidence. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  18. The operations and decisions taken after a disaster with a view to restoring a stricken community to its former living conditions, in particular with a view to restoring life lines and key services.
  19. The ratio of the amount of water vapor in the air compared to the amount required for saturation (at a particular temperature and pressure). Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  20. he technology of acquiring data and information about an object or phenomena by a device that is not in physical contact with it. In other words, remote sensing refers to gathering information about the Earth and its environment from a distance, a...
  21. The ability of a system, community or society exposed to hazards to resist, absorb, accommodate to and recover from the effects of a hazard in a timely and efficient manner, including through the preservation and restoration of its essential basic...
  22. A measure of the ability to separate observable quantities. In the case of imagery, it describes the area represented by each pixel of an image. The smaller the area represented by a pixel, the more accurate and detailed the image. Source: NASA (...
  23. The provision of emergency services and public assistance during or immediately after a disaster in order to save lives, to reduce health impacts, to ensure public safety and to meet the basic subsistence needs of the people affected.
  24. An east-to-west orbit of Earth (Earth spins west to east). See prograde orbit. Source: NASA (http://earthobservatory.nasa.gov/Glossary)
  25. Process of the Earth circling the sun in its orbit. Revolution determines the seasons, and the length of the year. In addition, differences in seasons occur because of Earth's inclination (tilt on its axis) of about 23.5 degrees as it revolves...
  26. Process of the Earth turning on its axis. Rotation determines day and night, and the length of the day. Compare with revolution. Source: NASA (http://earthobservatory.nasa.gov/Glossary)