Abstract: In De Broyer C, Koubbi P, Griffiths HJ, Raymond B, d’Udekem d’Acoz C, Van de Putte AP, Danis B, David B, Grant S, Gutt J, Held C, Hosie G, Huettmann F, Post A, Ropert-Coudert Y (eds) Biogeographic Atlas of the Southern Ocean. Publisher: Scientific Committee on Antarctic Research, Cambridge

Abstract: Two electromagnetic models were used to simulate snow emission at L-band from in situ measurements of snow properties collected at Dome C in Antarctica. Two different approaches were used: one based on the radiative transfer theory and the other on the wave approach. The soil moisture ocean salinity (SMOS) satellite observations performed at 1.4 GHz (21 cm) were used to check the validity of these models. Model results based on the wave approach were in good agreement with SMOS observations, particularly for incidence angles lower than 55°. Comparisons suggest that the wave approach is more suitable to simulate brightness temperature at L-band than the transfer radiative theory, because interference between the layers of the snowpack is better taken into account. The model based on the wave approach was then used to investigate several L-band characteristics at Dome C. The emission e-folding depth, i.e., 67% of the signal, was estimated at 250 m, and 99% of the signal emanated from the top 900 m. L-band brightness temperature is only slightly affected by seasonal variations in surface temperature, confirming the high temporal stability of snow emission at low frequency. Sensitivity tests showed that good knowledge of density variability in the snowpack is essential for accurate simulations in L-band.

Abstract: The Southern Hemisphere`s westerly winds play a vital role in regulating Earth`s climate by shielding Antarctic ice from low latitude heat, driving global ocean circulation and storing vast amounts of CO2. Both strength and position of this globally significant atmospheric pattern are rapidly shifting in the face of ongoing warming. A string of recent studies links these developments to dramatic changes in temperature, precipitation, sea ice extent and cryosphere stability unfolding throughout the Southern Ocean region. Critically, a lack of baseline information restricts our ability to understand the causes and patterns of these shifts and represent them in the future projections that underpin climate policies. Especially in the Southern Ocean, there are few time series recording past climate due to few suitable land areas and the few Sub-Antarctic Islands is remote and has cumbersome logistics. Kerguelen Island is located within the Antarctic Circumpolar Current and the Southern Westerly wind belt and contains several glaciers and smaller ice caps. Terrestrial archives recording past history of the glaciers at Kerguelen thus have a unique potential to record past changes in oceanic and atmospheric circulation patterns from southern mid latitudes. Here we present results from the first distal glacier fed lake study at the Kerguelen Island. A 2.8 m long sediment core was obtained from Lac Guynemer (121masl.), a lake that receives glacial meltwater from Glacier Guynemer at the Pic Guynemer (1188masl.), located at the Peninsule Loranchet at the northern part of Kerguelen Island. The sediment core has been analyzed with highresolution core scanning X-ray fluorescence (XRF), CT scanning, magnetic parameters, loss on ignition and dry bulk density, to reconstruct past glacier variability of Glacier Guynemer. The sediment record covers an interval over c. 1000 – 3500 cal. yr BP and show dynamic glacier variability during the Neoglacial time period, in phase with other glaciers reconstructed from the Southern Hemisphere.