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The radar altimeter is a short pulse, nadir viewing radar designed to
mesure precisely the distance from the satelite to the Earth surface.
The instrument can also measure the shape of the returned pulse and
the backscattering cross section. The latter two measurements permit
inference of significant wave height and wind speed. The significant
wave height can be inferred from the slope of the leading edge of the
returned pulse and the wind speed can be inferred from the rqdar cross
section. Higher waves tend to decrease the slope of the leading edge
of the pulse and also the backscattering, thus leading to the
inference of the presence of higher winds. The major component of
information derived from a nadir altimeter pertains to the geoid and
small-scale anomalies. These anomalies may be caused by sea mounts,
trenches, ocean currents, and fronts.
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Entry taken from:
Rao, P.K., S.J. Holmes, R.K. Anderson, J.S. Winston, P.E. Lehr,
Weather Satellites: Systems, Data, and Environmental
Applications, American Meteorological Society, Boston, 1990.
ISBN 0-933876-66-1
Reference online documentation:
"http://earth.esa.int/services/esa_doc/doc_gen.html"
"http://esapub.esrin.esa.it"
For any query, please refer to:
ESA/ESRIN Earth Observation Help Desk
"http://earth.esa.int"
E-mail: eohelp@esa.int
Phone: +39 06 94180777
Fax: +39 06 94180292
Address:
ESA/ESRIN
Via G.Galilei
00044 Frascati
Italy
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| Abstract from DBPedia | A radar altimeter (RA), also called a radio altimeter (RALT), electronic altimeter, reflection altimeter, or low-range radio altimeter (LRRA), measures altitude above the terrain presently beneath an aircraft or spacecraft by timing how long it takes a beam of radio waves to travel to ground, reflect, and return to the craft. This type of altimeter provides the distance between the antenna and the ground directly below it, in contrast to a barometric altimeter which provides the distance above a defined vertical datum, usually mean sea level.電波高度計（でんぱこうどけい radar altimeter）は電波を用いた高度計。航空機もしくは宇宙船より地上へ電波を発し、自機の対地高度を測定する。レーダーの一種。 (Source: http://dbpedia.org/resource/Radar_altimeter) |
