000206727 001__ 206727
000206727 005__ 20180913063039.0
000206727 037__ $$aPOST_TALK
000206727 245__ $$aSpatially-resolved mean flow and turbulence help explain observed erosion and deposition patterns of snow over Antarctic sea ice
000206727 269__ $$a2014
000206727 260__ $$c2014
000206727 336__ $$aTalks
000206727 520__ $$aSea ice-atmosphere interactions are major drivers of patterns of sea ice flows and deformations in Polar regions, and affect snow erosion and deposition at the surface. Here, we combine analyses of sea ice surface topography at very high-resolutions (~1-10 cm), and Large Eddy Simulations (LES) to study surface drag and snow erosion and deposition patterns from process scales to floe scales (~ 1 cm – 100 m). The snow/ice elevations were obtained using a Terrestrial Laser Scanner during the SIPEX II (Sea Ice Physics and Ecosystem eXperiment II) research voyage to East Antarctica (September-November 2012). LES are performed on a regular domain adopting a mixed pseudo-spectral/finite difference spatial discretization. A scale-dependent dynamic subgrid-scale model based on Lagrangian time averaging is adopted to determine the eddy-viscosity in the bulk of the flow. Effects of larger-scale features of the surface on wind flows (those features that can be resolved in the LES) are accounted for through an immersed boundary method. Conversely, drag forces caused by subgrid-scale features of the surface should be accounted for through a parameterization. However, the effective aerodynamic roughness parameter z0 for snow/ice is not known. Hence, a novel dynamic approach is utilized, in which z0 is determined using the constraint that the total momentum flux (drag) must be independent on grid-filter scale. We focus on three ice floe surfaces. The first of these surfaces (October 6, 2012) is used to test the performance of the model, validate the algorithm, and study the spatial distributed fields of resolved and modeled stress components. The following two surfaces, scanned at the same location before and after a snow storm event (October 20 and 23, 2012), are used to propose an application to study how spatially resolved mean flow and turbulence relates to observed patterns of snow erosion and deposition. We show how erosion and deposition patterns are correlated with the computed stresses, with modeled stresses having higher explanatory power. Deposition is mainly occurring in wake regions of specific ridges that strongly affect wind flow patterns. These larger ridges lock in place elongated streaks of relatively high speeds with axes along the stream-wise direction, and which are largely responsible for the observed erosion.
000206727 700__ $$0246076$$g220577$$aTrujillo Gomez, Ernesto
000206727 700__ $$0246172$$g218957$$aGiometto, Marco Giovanni
000206727 700__ $$0246013$$g221032$$aLeonard, Katherine Colby
000206727 700__ $$aMaksym, Ted L.
000206727 700__ $$aMeneveau, Charles V.
000206727 700__ $$0242902$$g155043$$aParlange, Marc
000206727 700__ $$g167659$$aLehning, Michael$$0245914
000206727 7112_ $$dDecember 15-19, 2014$$cSan Francisco, CA, USA$$aAGU Fall Meeting, Abstract C22A-04
000206727 909C0 $$xU12533$$0252326$$pCRYOS
000206727 909C0 $$xU11028$$0252105$$pEFLUM
000206727 909CO $$ppresentation$$pENAC$$ooai:infoscience.tind.io:206727
000206727 917Z8 $$x220577
000206727 937__ $$aEPFL-TALK-206727
000206727 973__ $$aEPFL
000206727 980__ $$aTALK