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DOI

  • Etienne Vignon
  • Frédéric Hourdin
  • Christophe Genthon
  • Hubert Gallée
  • Eric Bazile
  • Marie Pierre Lefebvre
  • Jean Baptiste Madeleine
  • Bas J.H. Van de wiel

The parametrization of the atmospheric boundary layer (ABL) is critical over the Antarctic Plateau for climate modelling since it affects the climatological temperature inversion and the negatively buoyant near-surface flow over the ice-sheet. This study challenges state-of-the-art parametrizations used in general circulation models to represent the clear-sky summertime diurnal cycle of the ABL at Dome C, Antarctic Plateau. The Laboratoire de Météorologie Dynamique-Zoom model is run in a 1-D configuration on the fourth Global Energy and Water Cycle Exchanges Project Atmospheric Boundary Layers Study case. Simulations are analyzed and compared to observations, giving insights into the sensitivity of one model that participates to the intercomparison exercise. Snow albedo and thermal inertia are calibrated leading to better surface temperatures. Using the so-called "thermal plume model" improves the momentum mixing in the diurnal ABL. In stable conditions, four turbulence schemes are tested. Best simulations are those in which the turbulence cuts off above 35 m in the middle of the night, highlighting the contribution of the longwave radiation in the ABL heat budget. However, the nocturnal surface layer is not stable enough to distinguish between surface fluxes computed with different stability functions. The absence of subsidence in the forcings and an underestimation of downward longwave radiation are identified to be likely responsible for a cold bias in the nocturnal ABL. Apart from model-specific improvements, the paper clarifies on which are the critical aspects to improve in general circulation models to correctly represent the summertime ABL over the Antarctic Plateau.

Original languageEnglish
Pages (from-to)6818-6843
JournalJournal Of Geophysical Research-Atmospheres
Volume122
Issue number13
DOIs
Publication statusPublished - 2017

    Research areas

  • Antarctic Plateau, Atmospheric boundary layer, GABLS4, General circulation model, Physical parametrizations

ID: 22714321