Improved global maps and 54‐year history of wind‐work on ocean inertial motions

[1] The global distribution and 54-year time dependence of the energy-flux from the wind to near-inertial motions is computed by driving a slab mixed-layer model with NCEP/NCAR Reanalysis winds, improving upon previous estimates [Alford, 2001; Watanabe and Hibiya, 2002]. The slab model is solved spectrally with frequency-dependent damping. The resulting solutions are more physically sensible than the previous, and more skillful at high latitudes, where the inertial frequency approaches the 4×-daily sampling of the Reanalysis winds. This enables Alford's calculation, whose domain was limited to ±50°, to be extended to the poles. The high-latitude reliability is demonstrated by direct comparison with a high-resolution regional model (REMO) in the NE Atlantic. The total power input, 0.47 TW, has increased by 25% since 1948, paralleling observed increases in extratropical cyclone frequency and intensity. If believable, the trend may have important consequences for modulation of the meridional overturning circulation.

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