Started in 2006, the objective of the Hydro-sensor-FLOWS project (2006-2010, IPY#16) is to investigate the hydrology of the Loven-East Glacier basin (10 km2, Brøgger peninsula, Svalbard) by continuous monitoring of the dynamics of the runoff , the snow cover, the ablation/accumulation limit of the glacier and the glacier itself. The project is coordinated by M. Griselin (UMR Th ema, Besançon) and C. Marlin (UMR IDES, Orsay) in association with SET (Pau), FEMTO (Besançon) and AWI (Potsdam).
During the 2008 field work, we gathered hydroglacio- climatological data for a second complete hydrological year, that allows a comparison with the past year (2006-2007). Th e hydrological year 2007-2008 is different than last year: the winter 2007-2008 was much more snowy and the summer was colder, with less direct radiation. This provides a glaciological balance more favourable for the glacier than in 2006-2007. The volume variation of snow and ice of the glacier is known by the set-up of 30 ice stakes and the 30 snow drill holes. The data obtained by the recorders (multi-parameters probes) set up on the catchment (outlet and two tributaries), as well as those obtained by chemical and isotopic analysis on water samples, allowed us to address the cause-effect relationships between the various parameters involved (climate, geological, hydrological) on the runoff at a daily and hourly time-scale. The data show that the runoff is more dependent on thermal conditions on the glacier than on the amount of precipitation. The flood peaks are controlled both by the amount of heat accumulated on the glaciers of the period 24 hours or 48 hours before the flood and the amount of precipitation if any. The isotopic measurements (O-18 and H-2) have been used to study the origin of water at the outlet: the separation of flows between supra-glacial meltwater at various altitudes and subglacial water is possible.
Since 2007, the CLIMAFLU ANR project is dedicated to the study of the impact of the recent global warming on the erosional process of the largest arctic fluvial system, the Lena River in Yakutia, by means of hydro-climatic data and spatial analysis of fluvial forms mobility. Th is project is coordinated by F. Costard (IDES laboratory, Orsay) and E. Gautier and D. Brunstein (Laboratoire de Géographie Physique, Meudon) in cooperation with Prof. F. Fedorov and P. Konstantinov from the Permafrost Institute in Yakutsk, Russia. The flood plain at the latitude of Yakutsk is dominated by outburst floods within a continuous and deep permafrost zone. On the basis of the satellite image analysis, different sites have been selected, where precise topographic and bathymetric surveys have been conducted in May and August 2008. The use of a laser theodolite on dewatered areas, will allow the elaboration of annual Digital Elevation Models. The comparison of these DEM before and after the annual flood will give precise information about the efficiency of the discharge on the spatial distribution of erosion and sedimentation. The precise topographic and bathymetric surveys are completed by sediment trapping systems. By this way, we will evaluate the annual bank retreat of channels and islands and to quantify the annual deposition. Different data loggers have been used to evaluate the evolution of the permafrost thermal regime with time for the next few years.
Dr. Decaulne (CNRS UMR 6042 Geolab and GDR 3062 Mutations Polaires) develops the Holocene slope activity research in subpolar areas from stratigraphical profi les analysis in Northern Iceland. Results show an increasing activity of mass movements during the last 1000 years, without pronounced climatic signals, but with probable implication from human activity. Also, in a natural hazard and risk mitigation perspective, she pursues her work on geomorphic evidence of past- and present-day snow avalanches and debris fl ows, both in the direct surrounding of inhabited areas and in remote areas to recognise extreme events occurrence and magnitude. This research is carried out in partnership with Dr. Þ. Sæmundsson, director of the Natural Research Center of Northwestern Iceland, Sauðárkrókur, Iceland. Collaboration with S. Conway, Open University, UK, took a step further with the second field season carried in Northwest Iceland on the comparison of terrestrial and Martian debris flows. Dr. Decaulne is also the Geosciences Coordinator within the group of Association of Polar Early Career Scientists.
The periglacial group of the University of Caen (UMR CNRS 6143) carried out laboratory experiments to address the genesis of Martian gullies observed on sand dunes (collaborator F. Costard, UMR CNRS 8148). Preliminary results suggest that the typical morphology of gullies observed on Mars can best be reproduced by the formation of linear debris flows related to the melting of a near-surface ground ice within silty materials. This physical modelling highlights the role of the periglacial conditions, especially the active-layer thickness during debrisflow formation.
François Costard (firstname.lastname@example.org)