Chapter 5. SPATIALLY-COHERENT STRUCTURES
Figure 5-9. Comparison of the WKB-scaled (a, b) density displacement and (c, d) horizontal
velocity spectra from the R/V Le Noroit South-to-North and North-to-South meridional
sections (5
o S to 5
o N) with the internal wave towed spectral model. The experimental spectra
(bold lines) are averaged within the depth range from 60 to 110 m. The model spectra (thin
lines) represent the sum of the Feng et al. (1998b) tidal model and the Garrett-Munk
wavenumber spectrum. Confidence intervals are also shown. The ADCP and SEASOAR data
were collected by Eric Firing and Kelvin Richards.
Cabanes (1999) analyzed the modulation of the mixed layer
thermodynamics by a long ( IG
O ~1000 km), equatorial inertia-gravity wave
using a quasi-two-dimensional model of PWP type (Price et al., 1994). He
concluded that these waves could produce mixed layer temperature and
salinity anomalies with the same horizontal length scale and a cascade of
smaller scale anomalies due to the differential entrainment depending on the
internal wave shear and atmospheric forcing.
Tidal motions constitute a significant fraction of the background velocity
field in the COARE domain (note tidal peaks on the spectra from north-tosouth sections in Figure 5-9). Having low vertical mode structure away from
their generation region, the internal tidal waves have relatively small shear
(Pinkel, 2000). The M 2 baroclinic tidal wave in the western equatorial
299
Figure 5-9. Comparison of the WKB-scaled (a, b) density displacement and (c, d) horizontal
velocity spectra from the R/V Le Noroit South-to-North and North-to-South meridional
sections (5
o S to 5
o N) with the internal wave towed spectral model. The experimental spectra
(bold lines) are averaged within the depth range from 60 to 110 m. The model spectra (thin
lines) represent the sum of the Feng et al. (1998b) tidal model and the Garrett-Munk
wavenumber spectrum. Confidence intervals are also shown. The ADCP and SEASOAR data
were collected by Eric Firing and Kelvin Richards.
Cabanes (1999) analyzed the modulation of the mixed layer
thermodynamics by a long ( IG
O ~1000 km), equatorial inertia-gravity wave
using a quasi-two-dimensional model of PWP type (Price et al., 1994). He
concluded that these waves could produce mixed layer temperature and
salinity anomalies with the same horizontal length scale and a cascade of
smaller scale anomalies due to the differential entrainment depending on the
internal wave shear and atmospheric forcing.
Tidal motions constitute a significant fraction of the background velocity
field in the COARE domain (note tidal peaks on the spectra from north-tosouth sections in Figure 5-9). Having low vertical mode structure away from
their generation region, the internal tidal waves have relatively small shear
(Pinkel, 2000). The M 2 baroclinic tidal wave in the western equatorial
299