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Bouhier, Nicolas; Tournadre, Jean; Remy, Frederique; Gourves-cousin, Rozenn. |
The evolution of the thickness and area of two large southern ocean icebergs, having drifted in open water for more than a year, is estimated through the combined analysis of altimeter data and visible satellite images. Most of the iceberg modelling studies uses two main melting formulations that are compared with the observed thickness evolution of our two icebergs, to test their validity in case of large icebergs. The first formulation, based on a fluid dynamics approach, would tend to underestimate basal melt rates, so that using the second one (using a thermodynamic budget consideration) may be more relevant. Fragmentation is, before melting, the major decay process of large icebergs, yet it is a complex and still poorly documented mechanism. A... |
Tipo: Text |
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Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00410/52119/52827.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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Berthier, Etienne; Le Bris, Raymond; Mabileau, Laure; Testut, Laurent; Remy, Frederique. |
We observed the wastage of ice masses on the Kerguelen Islands ( Indian Ocean, 49 degrees S, 69 degrees E) using historical information and recent satellite data. Overall, the total ice-covered area on the islands declined from 703 to 552 km(2) between 1963 and 2001, a reduction of 21%. The area of Cook ice cap ( the main ice body) decreased asymmetrically from 501 to 403 km(2). West flowing glaciers lost 11% of their area, while east flowing glaciers lost 28%. After 1991, the retreat rate accelerated from 1.9 km(2)/a ( 1963-1991) to 3.8 km(2)/a ( 1991-2003). Between 1963 and 2000, the ice volume loss was 25-30 km(3), equivalent to an area-average ice-thinning rate of 1.4-1.7 m/a. The glacial retreat took place in the climatic context of a relatively low... |
Tipo: Text |
Palavras-chave: Ice caps; Climate change; Remote sensing; Kerguelen Islands; Southern Ocean; Mass balance. |
Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00219/33069/31557.pdf |
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