FN Archimer Export Format
PT J
TI Surface Roughness Imaging of Currents Shows Divergence and Strain in the Wind Direction
BT 
AF RASCLE, Nicolas
   CHAPRON, Bertrand
   PONTE, Aurelien
   ARDHUIN, Fabrice
   KLEIN, Patrice
AS 1:1,2,4;2:1;3:3;4:1,5;5:3,5;
FF 1:;2:PDG-ODE-LOS;3:PDG-ODE-LPO;4:PDG-ODE-LOS;5:;
C1 Inst Francais Rech Exploitat Mer, Lab Oceanog Spatiale, Plouzane, France.
   Univ Cape Town, Dept Oceanog, Nansen Tutu Ctr, ZA-7700 Rondebosch, South Africa.
   Inst Francais Rech Exploitat Mer, Lab Phys Oceans, Plouzane, France.
C2 IFREMER, FRANCE
   UNIV CAPE TOWN, SOUTH AFRICA
   IFREMER, FRANCE
   UBO, FRANCE
   CNRS, FRANCE
SI BREST
SE PDG-ODE-LOS
   PDG-ODE-LPO
IN WOS Ifremer jusqu'en 2018
   copubli-france
   copubli-univ-france
   copubli-int-hors-europe
   copubli-sud
IF 2.856
TC 19
UR https://archimer.ifremer.fr/doc/00210/32170/30619.pdf
LA English
DT Article
DE ;Circulation/ Dynamics;Ageostrophic circulations;Atmosphere-ocean interaction;Mesoscale processes;Wind waves;Atm/Ocean Structure/ Phenomena;Boundary layer;Sea state
AB Images of sea surface roughness-for example, obtained by synthetic aperture radars (SAR) or by radiometers viewing areas in and around the sun glitter-at times provide clear observations of meso- and sub-mesoscale oceanic features. Interacting with the surface wind waves, particular deformation properties of surface currents are responsible for those manifestations. Ignoring other sources of surface roughness variations, the authors limit their discussion to the mean square slope (mss) variability. This study confirms that vortical currents and currents with shear in the wind direction shall not be expressed in surface roughness images. Only divergent currents or currents with no divergence but strained in the wind direction can exhibit surface roughness signatures. More specifically, nondivergent currents might be traced with a 45 degrees sensitivity to the wind direction. A simple method is proposed in order to interpret high-resolution roughness images, where roughness variations are proportional to partial derivative u/partial derivative x + alpha partial derivative v/partial derivative y, a linear combination of the along-wind and crosswind current gradients. The polarization parameter a depends upon the sensor look direction and the directional properties of the surface waves selected by the sensor. The use of multiple look directions or possible acquisitions with different wind directions shall thus help to retrieve surface currents from surface roughness observations.
PY 2014
PD AUG
SO Journal Of Physical Oceanography
SN 0022-3670
PU Amer Meteorological Soc
VL 44
IS 8
UT 000340349800011
BP 2153
EP 2163
DI 10.1175/JPO-D-13-0278.1
ID 32170
ER

EF