FN Archimer Export Format
PT J
TI An analytical study of the atmospheric boundary layer flow and divergence over a SST front
BT 
AF Ayet, Alex
   Redelsperger, Jean-Luc
AS 1:1,2;2:3;
FF 1:PDG-ODE-LOPS-SIAM;2:;
C1 Ifremer, CNRS, IRD, UBO/ Laboratoire d'Océanographie Physique et Spatiale (LOPS), IUEM Brest France
   LMD/IPSL, CNRS, École Normale SupérieurePSL Research University Paris France
   CNRS, Ifremer, IRD, UBO / Laboratoire d'Océanographie Physique et Spatiale (LOPS), IUEM Brest France
C2 IFREMER, FRANCE
   IPSL, FRANCE
   CNRS, FRANCE
SI BREST
SE PDG-ODE-LOPS-SIAM
UM LOPS
IN WOS Ifremer UMR
   WOS Cotutelle UMR
   copubli-france
IF 3.471
TC 5
UR https://archimer.ifremer.fr/doc/00501/61230/64808.pdf
LA English
DT Article
DE ;air-sea interaction;analytical model;boundary-layer flow;SST front
AB We present an analytical model reproducing literature‐based numerical simulations of the Marine Atmospheric Boundary Layer (MABL) over a SST front, with wind blowing from the cold to the warm side. Turbulence is parameterised through a varying diffusion coefficient with two critical features: it is parabolic on the vertical and its mean value is decoupled from the MABL height (unlike an Ekman layer model). These two novel features are found essential to recover the internal structure of the MABL from numerical simulations. Different dynamical regimes are obtained and interpreted in terms of non‐dimensional numbers characterising the relative importance of terms driving the momentum equation. A closed‐form expression of the vertically integrated wind divergence in the MABL is then obtained. The resulting divergence is linearly linked to the SST Laplacian and to the downwind SST gradient. This shows that the response of the MABL wind divergence to a SST front is highly dependent on its spatial scale. The coupling coefficients vary with the ratio of MABL height to turbulence strength, i.e. the inverse Ekman number. We further show different regimes in the rate of variation of the coupling coefficients, depending on the Ekman number value. This can result in qualitatively different vertical winds, having potential implications for the coupling of the MABL with the free troposphere. 
PY 2019
PD JUN
SO Quarterly Journal Of The Royal Meteorological Society
SN 0035-9009
PU Wiley
VL 145
IS 723
UT 000476244400001
BP 2549
EP 2567
DI 10.1002/qj.3578
ID 61230
ER

EF