TY - JOUR
T1 - Antarctic boundary layer parametrization in a general circulation model
T2 - 1-D simulations facing summer observations at Dome C
AU - Vignon, Etienne
AU - Hourdin, Frédéric
AU - Genthon, Christophe
AU - Gallée, Hubert
AU - Bazile, Eric
AU - Lefebvre, Marie Pierre
AU - Madeleine, Jean Baptiste
AU - Van de wiel, Bas J.H.
PY - 2017
Y1 - 2017
N2 - 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.
AB - 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.
KW - Antarctic Plateau
KW - Atmospheric boundary layer
KW - GABLS4
KW - General circulation model
KW - Physical parametrizations
UR - http://www.scopus.com/inward/record.url?scp=85022185566&partnerID=8YFLogxK
UR - http://resolver.tudelft.nl/uuid:43665025-00c0-4efb-885b-65f999e1ac52
U2 - 10.1002/2017JD026802
DO - 10.1002/2017JD026802
M3 - Article
AN - SCOPUS:85022185566
SN - 2169-897X
VL - 122
SP - 6818
EP - 6843
JO - Journal Of Geophysical Research-Atmospheres
JF - Journal Of Geophysical Research-Atmospheres
IS - 13
ER -