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Séminaires de C Mayer et A Lambrecht, Mardi 29 Septembre 2020 à 10h00 en salle Lliboutry, Bât. Glaciologie
Special meeting "High Mountain Asia" on September 28 and 29, 2020, Lliboutry room
Nous recevrons ces 2 jours de fin septembre des collègues suisses et allemands avec qui nous collaborons. Ce sera l’occasion de plusieurs séminaires, auxquels vous êtes tous et toutes convié(e)s. Venez nombreux(ses) !
- Lundi 28 septembre, à 14h30 : Martin Hoetzle (Department of Geosciences, Fribourg) nous parlera des glaciers d’Asie centrale, et Evan Miles (Swiss Federal Research Institute, Zurich), spécialiste des glaciers couverts de débris, nous présentera sa dernière étude sur les gradients de bilans de masse de tous les glaciers des hautes montagnes d’Asie.
- Mardi 29 septembre, à 10h : Astrid Lambrecht et Christoph Mayer (Bavarian Academy of Sciences, Munich) nous présenteront les résultats de leur campagne de terrain, effectuée avec Fanny en été 2019, sur le plus grand glacier de montagne du monde, le glacier Fedchenko au Tajiskistan (http://mountainhydrology.org/our-news/accumulation-measurements-in-the-pamir-mountains/).
We will welcome these 2 days at the end of September some Swiss and German colleagues with whom we collaborate. It will be the occasion of several seminars, to which you are all invited. Come and join us !
- On Monday, September 28, at 2:30 pm : Martin Hoetzle (Department of Geosciences, Fribourg) will talk about Central Asian glaciers, and Evan Miles (Swiss Federal Research Institute, Zurich), a specialist in debris-covered glaciers, will present his latest study on the mass balance gradients of all the glaciers in the high mountains of Asia.
- On Tuesday, September 29, at 10 am : Astrid Lambrecht and Christoph Mayer (Bavarian Academy of Sciences, Munich) will present the results of their field campaign, carried out with Fanny in August 2019, on the world’s largest mountain glacier, the Fedchenko glacier in Tajikistan (http://mountainhydrology.org/our-news/accumulation-measurements-in-the-pamir-mountains/).
Séminaire du Mardi 29 septembre, de 10h00 :
Fedchenko Glacier in the Pamir Mountains, long term observations and recent evolution
C. Mayer, A. Lambrecht
Bavarian Academy of Sciences and Humanities, Geodesy and Glaciology, Munich
Fedchenko glacier is by far the largest glacier in the Pamir Mountains of Tajikistan. Owing to early accurate mapping of the glacier it is possible to evaluate glacier changes over eight decades, which is an exceptionally long time period for this remote mountain region. During this time a total volume loss of 5 km³ was observed on the main trunk of the glacier, while the total area changed by only 1.4%. Thinning rates derived from ground observations and remote sensing information increased between 2000 and 2016 by a factor of 1.8 compared with 1928–2000, resulting in peak values of 1.5 m a-1. Even the highest accumulation basins above 5000 m elevation have been affected by glacier thinning with indications of recent intensification.
Accumulation rates vary considerably in the main accumulation basin of Fedchenko Glacier, with accumulation rates up to 2400 mm w.e. a−1 in the West, decreasing to < 1000 mm w.e. a−1 in the center, although the elevation difference is < 200 m. The combination of snow/firn samples and ground-penetrating radar profiles suggests that this accumulation pattern is persistent during the recent past, even though strong interannual variations exist. Modelling of trajectories, based on accumulation distribution and glacier geometry, results in an estimate of the depth/age relation close to the main divide. This region provides one of the most suitable locations for retrieving climate information with temporal high resolution for the last millennium, with a potential to cover most of the Holocene in less detail.