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Scatter Radar - Space Research from the Ground 1963 US Bureau of Standards
🕑 Added 2019-12-21 22:47:18 +0000 UTCmore at http://quickfound.net/
'Tells the story of Jicamarca Observatory, new National Bureau of Standards facility near Lima, Peru, and its fascinating new reserach projects. Jicamarca, largest institution of its kind in the world, uses a 22 acre antenna, probes the upper atmosphere to measure electron densities, makes observations of planets, and studies solar coronas and solar gases. Presents in a travelogue-like sequence, the search for a site for the Observatory near the magnetic equator, watches construction go forward in the arid Jicamarca Valley at the foot of the Andes, and, throughout, observes the cooperation of the Peruvian people and of the Instituto Geofisico del Peru, famous and historic ally-in-science of the National Bureau of Standards. The scatter radar technique is explained in simple animation sequences: high frequency radio waves penetrate the ionosphere; free electrons in the upper atmosphere respond by oscillating and scattering their energy incoherently; the ultra-powerful Jicamarca antenna picks up this faint incoherent scatter. Analysis of this new data, yielding information heretofore concealed, provides the basis for calling this new technique "space research from the ground."'
Originally a public domain film from the National Archives, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.
The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).
https://en.wikipedia.org/wiki/Ionosphere
Wikipedia license: http://creativecommons.org/licenses/by-sa/3.0/
The ionosphere (/aɪˈɒnəˌsfɪər/) is the ionized part of Earth's upper atmosphere, from about 60 km (37 mi) to 1,000 km (620 mi) altitude, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an important role in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on the Earth. The region below the ionosphere is called neutral atmosphere, or neutrosphere...
Incoherent scatter radars
Incoherent scatter radars operate above the critical frequencies. Therefore, the technique allows probing the ionosphere, unlike ionosondes, also above the electron density peaks. The thermal fluctuations of the electron density scattering the transmitted signals lack coherence, which gave the technique its name. Their power spectrum contains information not only on the density, but also on the ion and electron temperatures, ion masses and drift velocities...
https://en.wikipedia.org/wiki/Jicamarca_Radio_Observatory
The Jicamarca Radio Observatory (JRO) is the equatorial anchor of the Western Hemisphere chain of Incoherent Scatter Radar (ISR) observatories extending from Lima, Peru to Søndre Strømfjord, Greenland. JRO is the premier scientific facility in the world for studying the equatorial ionosphere. The Observatory is about half an hour drive inland (east) from Lima and 10 km from the Central Highway (11°57′05″S 76°52′27.5″W, 520 meters ASL). The magnetic dip angle is about 1°, and varies slightly with altitude and year. The radar can accurately determine the direction of the Earth's magnetic field (B) and can be pointed perpendicular to B at altitudes throughout the ionosphere. The study of the equatorial ionosphere is rapidly becoming a mature field due, in large part, to the contributions made by JRO in radio science.
JRO’s main antenna is the largest of all the incoherent scatter radars in the world. The main antenna is a cross-polarized square array composed of 18,432 half-wavelength dipoles occupying an area of approximately 300m x 300m. The main research areas of the observatories are: the stable equatorial ionosphere, ionospheric field aligned irregularities, the dynamics of the equatorial neutral atmosphere and meteor physics.
The Observatory is a facility of the Instituto Geofísico del Perú operated with support from the US National Science Foundation Cooperative Agreements through Cornell University...
