TY - JOUR

T1 - Systematic bias in baroclinic energy estimates in shelf seas

AU - Stephenson, Gordon

AU - Green, Mattias

AU - Inall, Mark E.

N1 - NERC through FASTNEt (grant NE/I030224/1)

PY - 2016/9

Y1 - 2016/9

N2 - A simple model of an internal wave advected by oscillating barotropic flowsuggests flaws in standard approaches to estimating properties of the internaltide. When the M2 barotropic tidal current amplitude is of similar size tothe phase speed of the M2 baroclinic tide, spectral and harmonic analysistechniques lead to erroneous estimates of the amplitude, phase, and energy inthe M2 internal tide. In general, harmonic fits and bandpass or low-pass filtersthat attempt to isolate the lowest M2 harmonic significantly underestimatethe strength of M2 baroclinic energy fluxes in shelf seas. Baroclinic energyflux estimates may show artificial spatial variability, giving the illusion ofsources and sinks of energy where none are present. Analysis of previouslypublished estimates of baroclinic energy fluxes in the Celtic Sea suggests thismechanism may lead some values to be 25 to 60% too low

AB - A simple model of an internal wave advected by oscillating barotropic flowsuggests flaws in standard approaches to estimating properties of the internaltide. When the M2 barotropic tidal current amplitude is of similar size tothe phase speed of the M2 baroclinic tide, spectral and harmonic analysistechniques lead to erroneous estimates of the amplitude, phase, and energy inthe M2 internal tide. In general, harmonic fits and bandpass or low-pass filtersthat attempt to isolate the lowest M2 harmonic significantly underestimatethe strength of M2 baroclinic energy fluxes in shelf seas. Baroclinic energyflux estimates may show artificial spatial variability, giving the illusion ofsources and sinks of energy where none are present. Analysis of previouslypublished estimates of baroclinic energy fluxes in the Celtic Sea suggests thismechanism may lead some values to be 25 to 60% too low

M3 - Article

VL - 46

JO - Journal of Physical Oceanography

JF - Journal of Physical Oceanography

SN - 0022-3670

IS - 9

ER -