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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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| Battaglia, Alessandro; Mroz, Kamil; Watters, Daniel; Ardhuin, Fabrice. |
| Attenuation from clouds and precipitation hinders the use of Ka-band in SARs, radar altimeters and in satellite link communications. The NASA-JAXA Global Precipitation Measurement (GPM) mission, with its core satellite payload including a dual-frequency (13.6 and 35.5 GHz) radar and a multifrequency passive microwave radiometer, offers an unprecedented opportunity for better quantifying such attenuation effects. Based on four years of GPM products, this article presents a global climatology of Ka-band attenuation caused by clouds and precipitation and analyses the impact of the precipitation diurnal cycle. As expected, regions of high attenuation mirror precipitation patterns. Clouds and precipitation cause two-way attenuation at 35.5 GHz in excess of 3 dB... |
| Tipo: Text |
Palavras-chave: Attenuation; Cloud and precipitation; Ka-band; Radar. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00600/71196/69562.pdf |
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| Verron, Jacques; Bonnefond, Pascal; Aouf, Lofti; Birol, Florence; Bhowmick, Suchandra A.; Calmant, Stephane; Conchy, Taina; Cretaux, Jean-francois; Dibarboure, Gerald; Dubey, A. K.; Faugere, Yannice; Guerreiro, Kevin; Gupta, P. K.; Hamon, Mathieu; Jebri, Fatma; Kumar, Raj; Morrow, Rosemary; Pascual, Ananda; Pujol, Marie-isabelle; Remy, Elisabeth; Remy, Frederique; Smith, Walter H. F.; Tournadre, Jean; Vergara, Oscar. |
| The India-France SARAL/AltiKa mission is the first Ka-band altimetric mission dedicated primarily to oceanography. The mission objectives were firstly the observation of the oceanic mesoscales but also global and regional sea level monitoring, including the coastal zone, data assimilation, and operational oceanography. SARAL/AltiKa proved also to be a great opportunity for inland waters applications, for observing ice sheet or icebergs, as well as for geodetic investigations. The mission ended its nominal phase after three years in orbit and began a new phase (drifting orbit) in July 2016. The objective of this paper is to highlight some of the most remarkable achievements of the SARAL/AltiKa mission in terms of scientific applications. Compared to the... |
| Tipo: Text |
Palavras-chave: Altimetry; Ka-band; Oceanography; Hydrology; Ice; Geodesy. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00600/71248/69623.pdf |
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| Verron, Jacques; Bonnefond, Pascal; Andersen, Ole; Ardhuin, Fabrice; Bergé-nguyen, Muriel; Bhowmick, Suchandra; Blumstein, Denis; Boy, François; Brodeau, Laurent; Crétaux, Jean-françois; Dabat, Mei Ling; Dibarboure, Gérald; Fleury, Sara; Garnier, Florent; Gourdeau, Lionel; Marks, Karen; Queruel, Nadège; Sandwell, David; Smith, Walter H.f.; Zaron, Ed. |
| The CNES/ISRO altimetric satellite SARAL/AltiKa was launched in February 2013 and since then has provided useful data for various scientific and operational applications in oceanography, hydrology, cryospheric sciences and geodesy. However, a Reaction Wheel problem forced relaxation of the repeatability constraint on the satellite’s orbit, which has been drifting slowly since July 2016. Beyond the expected contributions of this mission and its very good integration into the objectives of the constellation of altimetric satellites, it has become more and more apparent that specific contributions and innovations related to the main specification of SARAL/AltiKa, that is to say the use of the Ka-band, have clearly emerged. The advantages of the Ka-band are in... |
| Tipo: Text |
Palavras-chave: Satellite; Altimetry; Ka-band. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00607/71878/70573.pdf |
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