TY - JOUR T1 - Observation of swell dissipation across oceans A1 - Ardhuin,Fabrice A1 - Chapron,Bertrand A1 - Collard,Fabrice AD - Serv Hydrog & Oceanog Marine, F-29609 Brest, France. AD - IFREMER, Ctr Brest, Lab Oceanog Spatiale, F-29280 Plouzane, France. AD - Collecte Localisat Satellites, Div Radar, F-29280 Plouzane, France. UR - https://archimer.ifremer.fr/doc/00000/6452/ DO - 10.1029/2008GL037030 N2 - Global observations of ocean swell, from satellite Synthetic Aperture Radar data, are used to estimate the dissipation of swell energy for a number of storms. Swells can be very persistent with energy e-folding scales exceeding 20,000 km. For increasing swell steepness this scale shrinks systematically, down to 2800 km for the steepest observed swells, revealing a significant loss of swell energy. This value corresponds to a normalized energy decay in time beta = 4.2 x 10(-6) s(-1). Many processes may be responsible for this dissipation. The increase of dissipation rate in dissipation with swell steepness is interpreted as a laminar to turbulent transition of the boundary layer, with a threshold Reynolds number of the order of 100,000. These observations of swell evolution open the way for more accurate wave forecasting models, and provide a constraint on swell-induced air-sea fluxes of momentum and energy. Citation: Ardhuin, F., B. Chapron, and F. Collard (2009), Observation of swell dissipation across oceans, Geophys. Res. Lett., 36, L06607, doi: 10.1029/2008GL037030. Y1 - 2009/03 PB - American Geophysical Union JF - Geophysical Research Letters ( GRL ) SN - 0094-8276 VL - 36 IS - L06607 SP - 1 EP - 5 ID - 6452 ER -