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PATTYN Frank
Units
Person in charge of the Unit : Oui
The Laboratoire de Glaciologie of the Faculty of Sciences of the Université Libre de Bruxelles (ULB) is a research unit focused on the study of glaciers and ice sheets and their relation within the climate system.The GEMICE group (Geophysics and Modelling of Ice) is specialized in the development of numerical ice sheet models, applied to specific glaciological problems, such as grounding lines, ice streams, ice sheet/ice shelf transitions, subglacial lake interconnection, subglacial polythermal conditions etc. Validation of these models is currently done using overland and airborne geophysics, such as radio-echo sounding. Field work is concentrated on polythermal glaciers and Antarctic.The PROPICE (Properties of ice) group focuses on physico-chemical properties of ''interface ice'', such as ice-bedrock, ice-ocean or ice-atmosphere. This expertise is based on polar field expeditions (Arctic and Antarctic) and on the development of analytical techniques for the multi-parametric study of ice rich in solid or liquid impurities: texture and fabric, stable oxygen and hydrogen isotopes, total gas content and gas composition, bulk salinity, chemistry, etc.The main objective of the Laboratoire de Glaciologie is a better understanding of initial and boundary conditions of large ice masses (continental or marine), together with a comprehensive approach of the processes governing their interactions with the climate, more specifically in the framework of the potential impact of mankind on future climate at a global scale. It has been involved in EU Framework projects FP5, FP6 and FP7.The Laboratoire de Glaciology counts two academics who are responsible for teaching physical geography, glaciology and (palaeo-) climatology courses in the Bachelor of Geographical Sciences and the Master of Management and Science of the Environment of the ULB.
Projetcs
IDyRA - Ice Dynamics derived from englacial Radar reflection Architecture
IDyRA aims at improving our knowledge of the interaction between the ice sheet and the ice shelf (Antarctic grounding zones). It specifically aims at understanding the processes of subglacial melting and basal sliding by combining englacial information obtained from radio-echo sounding surveys withstate-of-the-art higher-order ice sheet models. This way, numerical ice-sheet models can be validated by reconstructing the internal layer architecture.Grounding lines are key areas in ice sheets and at present subject to much attention. IDyRA will improve the understanding of grounding line migration, ocean interaction, and the role of buttressing in east Dronning Maud Land, Antarctica, where the marine ice sheet is buttressed by numerous ice rises. Results of the project will contribute to a quantitative interpretation ofmelting under the ice shelf, its effect on ice sheet behavior and the effectof a thermohaline circulation under the ice shelf.
This project aims at studying ice flow, dynamics and rheology inside a 1 km3 ice cube, buried in the central part of the Antarctic ice sheet, in the vicinity of a subglacial lake. Ice Cube is initially an observatory for neutrinos in the vicinity of South Pole, the building of which has been completed in 2011. However, besides its mission of observation on cosmologic neutrinos detection, the site also has an interest for glaciologists: indeed the ice sheet deforms very slowly in these areas and only in its lower layers, the access of which has only been limited until now to scarce deep drilling projects (usually located at ice divides)
YROSIAE (Year Round survey of Ocean-Sea Ice-Air Exchanges in Antarctica)
As a result of field opportunities, BASICS-IPY has been mainly focused in the Antarctic on spring-summer pack ice studies. However, one of the targets of the International Polar Year was to extend polar research to less known areas and under-sampled time windows on the longer term. 'YROSIAE' will therefore aim at a year-round study of landfast sea ice in Scott Base,Antarctica. In the line of the previous investigations, the work will focus on the study of landfast sea ice physics and biogeochemistry in order to better understand and budget exchanges of energy and matter across the atmosphere-sea ice-ocean interfaces during ice growth and decay, and to quantify their potential impact on fluxes of climate gases (CO2, DMS, CH4, N2O) to the atmosphere and carbon export to the deep ocean. For the reasons developed above, the project will also specifically investigate the biogeochemical cycle of iron and other potentially important more specific/trace elements.
Dynamics of polythermal glaciers (Siberia, Alaska)
Determining basal conditions and ice thickness of polythermal glaciers by radio-echo sounding ; glacier modelling and response to climate change.
EPICA (European Project of Ice Coring in Antarctica)(ASPI)
Analysis of basal ice to be recovered by ice coring at Dome C, a place in East Antarctica where the ice thickness is more than 3500 m.
BELISSIMA (Belgian Ice Sheet-Ice Shelves Measurements in Antarctica)
The BELISSIMA (Belgian Ice Sheet ' Shelf Ice Measurements in Antarctica) project aims at improving our understanding and prediction of the cryospheric contribution to future sea level rise. The objectives are twofold: i) to investigate the deglaciation history and stability of ice rises (points where the ice shelf gets buttressed), and (ii) to investigate the role of ice-ocean interactions in the stability of the ice sheet ' ice shelf system. The project is within the framework of the newly established Princess Elisabeth Station (Antarctica) and the studied area is situated on the coastal stretch (Princess Ragnhild Coast, Dronning Maud Land), 180 km north from the research station, where a number of distinct ice rises have been identified. Field investigations are based on ground based ice-penetrating radar (Radio-echo sounding), differential GPS and ice core drilling. A multi-parametric analysis of the physical and chemical properties of the ice is carried out on the acquired samples. RES and D-GPS data are analysed using state-of-the-art techniques and modelling tools.
The aim of MISMIP (Marine Ice Sheet Model Intercomparison) is to evaluate how models simulate grounding line migration in ice sheets, i.e. interactions between ice sheets and the ocean. The main objective is to perform intercomparative modelling experiments in order to evaluate the iimportance of longitudinal stress coupling in the transition zone between ice sheet and ice shelves. This will improve our numerical models for prediction of ice mass loss from the continent to the oceans
VOSTOK (Deep Ice Core Drilling in Central Antarctica)(ASPI)
The drilling has been performed in a location where a subglacial lake some 250 X 50 Km in area, exists under 3800 meters of ice. The bottom 210 meters of ice is not of meteoric origin, but results from accretion of individual frazil ice crystals born in the water column, due to peculiar circulation patterns in the lake water. These are similar to those existing below ice shelves at the ice sheet margin.
In the context of global warming, the question of the stability of Antarctic ice shelves is critical for predicting any sea level rise. The behaviour of ice shelves is dependent on their boundary conditions. At the ice-ocean interface, these boundary conditions can be appraised by studying the properties of marine ice forming accretions at the base.
IceCon : constraining ice mass changes in coastal Dronning Maud Land, Antarctica.
The IceCon project aims at a better understanding of the past andpresent ice volumes and extension of the Antarctic ice sheet in Dronning MaudLand (DML) through a new series of measurements and observations inconjunction with ice sheet system modelling. Knowledge of past ice volumes areimportant, since the ice sheet is still reacting to what happened in the past,especially since the Last Glacial Maximum (LGM), roughly 18,000 years ago,when the Antarctic ice sheet was significantly bigger. IceCon's main hypothesis isthat the LGM ice sheet volume in Dronning Maud Land was not as big aspreviously predicted by large-scale ice sheet models, although it advanced as faronto the continental shelf.
NEEM (North Eemian greenland Ice Core)
NEEM is an international program of deep ice core drilling initiated during the International Polar Year. The principal challenge of NEEM is to obtain a high resolution trustable climatic record of the beginning of the Eemian and, if possible, of all or part of the preceding glacial period. An adequate location has been chosen in North West Greenland (77°30'N, 51°O) on echo-sounding grounds. The ULB contribution lies in the analysis of the NEEM basal ice layers and in the modelling of ice flow around the site
BIGSOUTH (BIoGeochemical cycles in the SOUTHern Ocean: Role within the Earth System)
This proposal linking sea ice to the global ocean system focuses on the following key questions: (1) What is the significance of sea-ice physical and biogeochemical processes on atmosphere - ocean fluxes of climate gases (CO2, DMS, CH4, N2O) and fluxes of matter (carbon, macro- and micro-nutrients) to the water column? (2) Can we reconstruct paleo-sea ice extension based on sedimentary records and sound knowledge of sea-ice biological and physico-chemical processes? (3) How are formation rate, composition, lability and sinking speed of marine biogenic particles related to planktonic community structure and trophic interactions and how do margin systems open ocean and sea-ice covered systems, which differ in Fe availability, compare? (4) What are the physical and ecosystem conditions and pathways that lead either to shallow remineralisation or to deep export of organic matter produced in sea-ice and surface waters? (5) What is the impact of these processes on water column nutrient ratios and nutrient distribution in the Global Ocean?
Continental ice melting (glaiers and ice sheets) is one of the causes of rising sea level. This melting accelerates faster than predictions. Indeed, the last GIEC report showed that the greatest incertitudes come from estimates of sea level rise from ice sheet melting. Moreover, the same report underlines that our understanding of the mechanisms underlying ice sheet melting need to be bettered in order to improve our predictions on future sea level rise. The Ice2Sea program gathers european and international partners in order to reduce those incertitudes. This is an EU FP7 program composed of 5 Workpackages. ULB is leading the ''glacial processes'' workpackage.
The clear facies basal ice from Alpine glaciers shows similarities with the dispersed facies of sub-polar glaciers. It results from modifications of glacier ice close to bedrock. Its spatial distribution and physico-chemical characteristics are however poorly known, as well as its role in glacier dynamics and interactions with the subglacial hydrochemistry. This project links field observations (Tsanfleuron Glacier, Switzerland; Engabreen, Norway) and a mathematical model for the formation of this facies.
