M2 summary

[kurtisanstey]

• Notable effects: Apparent blue-shift. Strongest shelf and canyon-axis intensification effects. Seasonality (summer lull).

Semidiurnal outline

Upper Slope - Near-shelf intensification

Describe (what do I see):

• Depth-averaged / multi-annual time-averaged PSD comparison to K1 and M2 (K1 < f < M2, shape of peak, etc.).
• Identify critical frequency for slope below the Upper Slope ADCP.
• Some apparent blue-shift in spectral peak.
• Fairly equally distributed between cross- and along-slope, with along-slope slightly stronger above -250 m.
• Nearly entirely CW, as expected for Coriolis affected motions in the northern hemisphere.
• Intensification of about 2x orders of magnitude in both cross- and along-slope, and CW components, below -250 m.
• Lesser CCW intensification below -250 m (as at K1, about an order of magnitude).
• Vertical scale of effect about 150 m AB.
• Seasonality is mostly evident in the late-spring, with lesser pulses in the winter (as at K1, compare to wind data), and a reduction in the summer months, mostly evident in the bottom-intensified layer below -250 m.
• There is spring-neap modulation, similar to K1 (depth-mean vs surface tides align).
• Be sure these are all quantified and related in clear figures.

Compare (what did others see):

• Drakoupolos & Marsden, 1993.
• Foreman & Thomson, 1997.
• Polzin et al., 1997.
• Jane & St. Laurent, 2001.
• Nash et al., 2004.
• Kelly et al., 2010.
• Klymak et al., 2012.
• Kunze et al., 2012.
• Klymak et al., 2013.
• Terker et al., 2014.
• Johnston & Rudnick, 2014.
• Gemmrich & Klymak, 2015.
• Quantify (compare) where possible.
• Find additional sources.

Explain (what may be causing this):

• Discuss strengths and weaknesses of each theory.

Axis - Canyon-axis intensification

Describe (what do I see):

• Depth-averaged / multi-annual time-averaged PSD comparison to f and M2 (f < K1 < M2, shape of peak, etc.).
• Identify critical frequency for canyon-axis slope (and perhaps the walls).
• Some apparent blue-shift in spectral peak.
• Mostly along-canyon, rectilinear, as expected for canyon-guided flow.
• Below -750 m intensification in along-canyon, CW and CCW signals, of about 2x orders of magnitude (as seen in K1, etc.).
• Vertical scale of effect approximately 250 m AB.
• Seasonality is mostly evident in the late-fall/winter, with an apparent reduction through the summer, mostly evident in the bottom-intensified layer below -750 m.
• There is spring-neap modulation, similar to K1 (depth-mean vs surface tides align).
• Be sure these are all quantified and related in clear figures.

Compare (what did others see):

• Hotchkiss & Wunsch, 1982.
• Petruncio et al., 1998.
• Kunze et al., 2002.
• Carter & Gregg, 2002.
• Xu & Noble, 2009.
• Wain et al., 2013.
• Alberty et al., 2017.
• Kampf, 2018.
• Hamann & Alford, 2020.
• Quantify (compare) where possible.
• Find additional sources.

Explain (what may be causing this):

• Discuss strengths and weaknesses of each theory.

[kurtisanstey]

Reorganised into new issues (this will be kept for specific reference).