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| Titel |
Investigation of the atmosphere and surface of Venus by use of reanalysis of the radio occultation data of Venera-9, 10, and 15, 16 satellites |
| VerfasserIn |
Alexander Pavelyev, Alexander Zaharov, Oleg Rzhiga |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250051893
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| Zusammenfassung |
| The insertion of the Venera-9,10 and -15,16 spacecraft into orbits around Venus affords the
opportunity to make the bistatic and monostatic radar experiments on Venus. The main
objective of these experiments is to study the topography and to measure the ground density
of the planet. However, besides this objective, new data were obtained during the bistatic
radar experiments on conditions of refraction of radio waves through the entire thickness
of the atmosphere of Venus. The possibility of measuring refraction effects arose
because the bistatic radar was done immediately before the spacecraft passed into
occultation by the planet. Therefore, the incident angle at reflection of the radio
waves from the surface was small, and the refraction effects were more strongly
evident. It should be noted also that the periodically repeated monostatic radar
observations of Venus from Earth give no information on refraction, since the main part
of the power reflected in the Earth direction is generated by a small region of the
surface of the planet for which the incident angle is close to 90°. The purpose of
the contribution is to describe the method and the results of the experiments to
measure the refraction of radio waves in the atmosphere of Venus by means of
bistatic radar. The authors present measured values of the refractive angle and the
coefficient of generalized spherical divergence of radio waves reflected from the
surface of Venus. The measurements were made at wavelength 32 cm in the bistatic
scheme using the Venera-9,10, and 15,16 spacecraft. Both the refraction angle and the
reflection coefficient were determined in the experiment from the measured frequency
difference between the direct and the reflected signals as a function of time, using the
trajectory data on spacecraft positions. The results of the measurements agree with the
theory of propagation of radio waves in the atmosphere of Venus. The work was
partly supported by grant of Russian Fund of Basic Research No. 10-02-01015-a. |
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