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| Tournadre, Jean; Lambin, J; Steunou, N. |
| The main instrument of the French-Indian Altika/ SARAL mission scheduled for launch in 2010, is the Kaband Altika altimeter. The high attenuation due to atmospheric water (liquid or vapor) at this frequency band is the major drawback of the use of Ka-band. In part I of this paper, the impact of rain/clouds on Ka-band data and on the accuracy of the estimates of the geophysical parameters have been analyzed and quantified using an analytical model of waveform. Waveform distortion and errors on the geophysical parameters can be significant especially for small dense clouds and rain cells. It is thus necessary to flag the data potentially affected by rain and clouds. The use of a single channel for Altika prevents the use of the classical dual-frequency rain... |
| Tipo: Text |
Palavras-chave: Rain/cloud flag; Rain and cloud impact; Ka band altimeter. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4721.pdf |
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| Vincent, Patrick; Steunou, N; Caubet, E; Phalippou, L; Rey, L; Thouvenot, E; Verron, J. |
| This paper describes the Ka-band altimetry payload and system that has been studied for several years by CNES, ALCATEL SPACE and some science laboratories. Altimetry is one of the major elements of the ocean observing system to be made sustainable through the GEOSS ( Global Earth Observation System of Systems) and GMES ( Global Monitoring of the Environment and Security) programs. A short review of some mission objectives to be fulfilled in terms of mesoscale oceanography in the frame of the GEOSS and GMES programs is performed. To answer the corresponding requirements, the approach consisting in a constellation of nadir altimeter is discussed. A coupled Ka-band altimeter-radiometer payload is then described; technical items are detailed to explain how... |
| Tipo: Text |
Palavras-chave: Altimeter; Radiometer; Ocean mesoscale circulation; Ka-band. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/00284/39508/38003.pdf |
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| Tournadre, Jean; Lambin, J; Steunou, N. |
| The AltiKa project developed by the French Centre National d'Etudes Spatiales is based on a wide-band Ka-band altimeter (35.75 GHz). The technical characteristic of the instrument will offer higher performance both in terms of spatial and vertical resolution that will lead to improved observation of ice, coastal areas, inland waters and wave height. An Indian Space Research Organization satellite, Saral will embark the AltiKa altimeter. The launch is scheduled at the end of 2010. The major drawback of Ka band use is the attenuation of the radar signal by atmospheric liquid water. Clouds and rain effects will thus be a strong constraining factor, because the altimeter link budget imposes an attenuation of less than 3 dB. The impact of rain and clouds on... |
| Tipo: Text |
Palavras-chave: Geophysical parameters estimates; Rain and cloud impact; Ka band altimeter. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4720.pdf |
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