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Radiation of inertial kinetic energy as near‐inertial waves forced by tropical Pacific Easterly waves
Author(s) -
Soares S. M.,
Richards K. J.
Publication year - 2013
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/grl.50387
Subject(s) - inertial wave , kinetic energy , atmospheric sciences , energy flux , turbulence kinetic energy , climatology , thermocline , turbulence , environmental science , mixed layer , dissipation , geology , geophysics , physics , meteorology , wave propagation , mechanical wave , longitudinal wave , quantum mechanics , astronomy , thermodynamics
Easterly waves (EW) are low level tropical atmospheric disturbances able to resonantly force strong mixed layer inertial currents. Using data from two Tropical Atmosphere Ocean/Eastern Pacific Investigation of Climate Processes (TAO/EPIC) buoys located along 95°W and a multiparameterization one‐dimensional turbulence model, we examine how the EW‐forced surface inertial kinetic energy (IKE) loss is partitioned between turbulent dissipation and near‐inertial wave (NIW) radiation. Several EW‐forcing events are individually simulated with a version of the General Ocean Turbulence Model modified to include a linear damping coefficient to account for the NIW radiation energy sink. The kinetic energy budget of these simulations shows that NIW radiation accounted for typically 50–60% of the IKE loss and in some cases up to 80%. These empirically derived estimates of the contribution of the radiated NIWs to the loss of wind‐induced surface IKE are substantially higher than recently published numerical estimates. Furthermore, the results indicate that the vertical NIW energy flux increases linearly with the wind input of IKE, an easily obtained quantity. The NIW vertical energy flux estimated for a single near‐resonant event is comparable to extreme north Pacific wintertime‐averaged fluxes, indicating the existence of important episodic sources of near‐inertial energy available for mixing within and below the thermocline in the tropical region.