HR: 1340h
AN: OS13A-1004    [Abstracts]
TI: Work done by the Wind on the Geostrophic Ocean Circulation: The Effect of Small Scales in the QuikSCAT Wind Stress Data.
AU: * Hughes, C W
EM: cwh@pol.ac.uk
AF: Proudman Oceanographic Laboratory, 6 Brownlow Street, Liverpool, L3 5DA, United Kingdom
AU: Wilson, C
EM: cwi@pol.ac.uk
AF: Proudman Oceanographic Laboratory, 6 Brownlow Street, Liverpool, L3 5DA, United Kingdom
AB: It has recently been noted that the effect of ocean currents on wind stress is visible in data from the QuickSCAT scatterometer. Duhaut and Straub suggested that this effect could have a significant impact on the work done on geostrophic currents by winds, reducing it by of order 20% in comparison to estimates which do not account for the effect of currents on wind stress. We calculate the work done, using a combination of wind stress (including the current effect) from scatterometer data, and currents from altimetry, drifter, and satellite gravity data. We find a global total of 0.76 TW, smaller than previous estimates, together with an estimate that the effect of currents should produce a reduction of 0.19 TW. This means that, if the data we are using are sufficiently well-sampled to resolve the correlations responsible for the current effect, calculations which do not account for the current effect would produce an estimate of 0.95 TW, a number which lies within the range of previous estimates. We test whether the sampling is sufficient by calculating the power based on a spatially smoothed version of the wind stress, which removes the effect of small-scale currents. This power is larger to approximately the expected degree in midlatitude regions, but not in the tropics, where something more complicated appears to be happening. The contribution of time-dependent terms to the average power produces a similar effect in regions dominated by mesoscale eddies.
DE: 4504 Air/sea interactions (0312, 3339)
DE: 4512 Currents
DE: 4520 Eddies and mesoscale processes
DE: 4528 Fronts and jets
DE: 4556 Sea level: variations and mean (1222, 1225, 1641)
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting