Using buoy data from the International Arctic Buoy Program, we found that sea ice mean speed has substantially increased over last 29 years (+17% per decade for winter and +8.5% summer). A strong seasonal dependence of is also revealed, with a maximum in October minimum April. The strain rate significantly period (+51% +52% We check these increases both deformation are unlikely to be consequences stronger atmospheric forcing. Instead, they suggest kinematics play fundamental role albedo...

IPCC climate models underestimate the decrease of Arctic sea ice extent.The recent decline is also characterized by a rapid thinning and an increase kinematics (velocities deformation rates), with both processes being coupled through positive feedbacks.In this study we show that observed trend factor almost 4 on average fail to capture associated accelerated motion.The coupling between state (thickness concentration) velocity unexpectedly weak in most models.In particular, drifts faster...

Sea ice drift and deformation from models are evaluated on the basis of statistical scaling properties. These properties derived two observation data sets: RADARSAT Geophysical Processor System (RGPS) buoy trajectories International Arctic Buoy Program (IABP). Two simulations obtained with Louvain‐la‐Neuve Ice Model (LIM) coupled to a high‐resolution ocean model simulation Los Alamos (CICE) were analyzed. compares well observations in terms large‐scale velocity field distributions...

Using buoy trajectories of the IABP data set, we analyze Arctic sea ice velocity field as superposition a mean and fluctuations. We study how can be objectively defined, using appropriate spatial temporal averaging scales depending on season considered: 400 km 5 months for winter (i.e., approximately all polar duration), 200 2 summer duration). The shows strong intra‐annual (between following summer) well interannual variability. fluctuations, i.e., remaining part after subtracting field,...

Abstract In Fram Strait, we combined underway-sampling using the remote-controlled Automated Filtration System for Marine Microbes (AUTOFIM) with CTD-sampling eDNA analyses, and high-resolution optical measurements in an unprecedented approach to determine variability plankton composition response physical forcing a sub-mesoscale filament. We determined biomass near surface horizontal resolution of ~ 2 km, addressed vertical at five selected sites. Inside filament, was tightly linked...

Ice single crystals were deformed under torsion and dislocation arrangements analyzed by synchrotron topography at ESRF (European Synchrotron Radiation Facility). Profile analysis of the topographs revealed scale-invariant character arrangement with long-range correlations. Dislocation density gradients are shown to be slightly anti-correlated as intensity profile is similar an anti-persistent random walk-like signal. This reveals influence internal stresses on up sample scale. Similar...

Abstract For the first time, to our knowledge, a scientific study of formation and evolution waterfall ice, ephemeral ice structures that form from freezing liquid water seeping on steep rock, was performed. We surveyed analysed three near Glacier d’Argentière, Mont Blanc massif, France, between winter 2007 spring 2009. reconstruct global two vertical using automatic digital cameras, while internal microstructure coring sampling. Macro- microstructural observations are considered, along with...

The ice microstructure (grain boundaries) is a key feature used to study evolution and investigate past climatic changes. We studied deep core, in Dome Concordia, Antarctica, which records mechanical deformations. measured "texture tensor" characterizes the pattern geometry reveals local heterogeneities of deformation along core. These results question assumptions current models for dating.

Sedimentary ancient DNA (sedaDNA) extracted from sediment cores is more frequently used to reconstruct past ecosystems and their biodiversity. When reconstructing vegetation components, are most often taken within terrestrial lake systems. Research on marine environments looking at the input has so far been based biogeochemical analyses. While studies into eukaryotes, especially diatoms, have conducted, it unknown whether or not plant sedaDNA sediments can be prevailing conditions...

Marine sediments contain abundant organic matter which forms a major carbon sink. About one third of it originates from land plants. The main source taxa and region as well the large-scale translocation are hitherto poorly understood, mainly because we lack proxy that can identify with high taxonomic resolution. Here, investigate plant component sedimentary ancient DNA in six globally distributed marine sediment cores for terrestrial quantity preservation taxa. spatial temporal composition...

Abstract The Southern Ocean plays a crucial role in the global carbon budget. Modeling studies propose that atmospheric CO 2 plateau during Antarctic Cold Reversal (ACR; 14,700 to 12,700 calibrated years before present (cal yr BP)) is related increased marine productivity. However, proxy evidence relating environmental conditions as well primary community composition and productivity drawdown missing. Our ancient DNA shotgun metagenomic analysis of sediments revealed Phaeocystis antarctica...

Terrigenous organic matter in marine sediments is considered a significant long-term carbon sink, yet our knowledge regarding its source taxa severely limited. Here, we leverage land-plant ancient DNA from six globally distributed sediment cores covering the Last Glacial-Holocene transition as proxy for share, accumulation rate, preservation, and composition of terrigenous matter. We show that spatial temporal plant revealed by sedaDNA records reflects mainly vegetation dynamics nearby...

Abstract. An original method to quantify the amplitude of inertial motion oceanic and ice drifters, through introduction a non-dimensional parameter M defined from spectral analysis, is presented. A strong seasonal dependence magnitude sea oscillations revealed, in agreement with corresponding annual cycles extent, concentration, thickness, advection velocity, deformation rates. The spatial pattern over Arctic basin also thickness concentration patterns. This argues for link between on one...

Abstract In Fram Strait, we combined underway-sampling using the remote-controlled Auto mated Fi ltration System for M arine Microbes (AUTOFIM) with CTD-sampling eDNA analyses, and high-resolution optical measurements in an unprecedented approach to determine variability plankton composition response physical forcing a sub-mesoscale filament. We determined biomass near surface horizontal resolution of ~ 2 km, addressed vertical at five selected sites. Inside filament, was tightly linked...

Cet article traite de l'etat actuel des recherches internationales sur les problemes d'ingenierie polaire. La diminution reserves petrole a relance l'idee, dans pays industrialises, construire et d'exploiter plates-formes forage conditions arctiques ou sub-arctiques. Les rencontres en Ingenierie polaire (plates-formes, ponts, barrages, navigation) sont ceux l'interaction glace-structure au cours laquelle se produit un endommagement la glace qui modifie alors son comportement mecanique. Des...