011-james.html (2610B)
1 <p>Considerable areas of the polar oceans are covered by sea ice, 2 formed by frozen sea water. The extent and thickness of the ice 3 pack influences local and regional ecology and climate. The ice 4 thickness is particularly important for the ice-cover survival 5 during warm summers. Wind and ocean currents compress and shear the 6 sea ice, and can break and stack ice into ridges. Current sea ice 7 models assume that the ice becomes increasingly rigid as ridges of 8 ice rubble grow. Modeling sea ice as bonded particles, we show that 9 ice becomes significantly weaker right after the onset of ridge 10 building. We introduce a mathematical framework that allows these 11 physical processes to be included in large-scale models.</p> 12 13 <p>Today a new paper of mine is published in the AGU-group journal 14 <a href="https://agupubs.onlinelibrary.wiley.com/journal/19422466">Journal 15 of Advances in Modeling Earth Systems</a>, and it is written with 16 co-authors <a href="https://scholar.princeton.edu/aos_sergienko/home">Olga 17 Sergienko</a> and <a 18 href="https://www.gfdl.noaa.gov/alistair-adcroft-homepage/">Alistair 19 Adcroft</a> at Princeton University (New Jersey, USA). I use my 20 program <a href="https://src.adamsgaard.dk/Granular.jl">Granular.jl</a> 21 for the simulations.</p> 22 23 <h2>Abstract</h2> 24 <blockquote> 25 <b>The Effects of Ice Floe-Floe Interactions on Pressure Ridging in Sea Ice 26 </b> 27 <br><br> 28 The mechanical interactions between ice floes in the polar sea-ice 29 packs play an important role in the state and predictability of the 30 sea-ice cover. We use a Lagrangian-based numerical model to investigate 31 such floe-floe interactions. Our simulations show that elastic and 32 reversible deformation offers significant resistance to compression 33 before ice floes yield with brittle failure. Compressional strength 34 dramatically decreases once pressure ridges start to form, which 35 implies that thicker sea ice is not necessarily stronger than thinner 36 ice. The mechanical transition is not accounted for in most current 37 sea-ice models that describe ice strength by thickness alone. We 38 propose a parameterization that describes failure mechanics from 39 fracture toughness and Coulomb sliding, improving the representation 40 of ridge building dynamics in particle-based and continuum sea-ice 41 models. 42 </blockquote> 43 44 <h2>Links and references:</h2> 45 <ul> 46 <li><a href="https://doi.org/10.1029/2020MS002336">Publication on journal webpage</a> (open access)</li> 47 <li><a href="https://src.adamsgaard.dk/seaice-experiments">Source code for producing figures</a></li> 48 <li><a href="https://src.adamsgaard.dk/Granular.jl">Simulation software</a></li> 49 </ul>