Hi, Kurtis:
I have read through your thesis proposal and have a number of edits and comments that I will save for our conference call. I think this is a challenging and worthwhile undertaking and you are off to a very good start. I am delighted that you are making good use of the ONC records and I quite like the spectral plots on pages 12 and 13. I am looking forward to seeing what you find with respect to the properties and origins of: (1) baroclinic diurnal shelf waves; (2) near inertial motions (are these blue-shifted internal waves of inertial period?); (3) semidiurnal (M2) tides; and (4) fM2 internal waves. A comparison of the spatial and temporal variability of the various forms of internal motions over the shelf and in the canyon should be especially interesting. I am also interested to learn if there are internal solibores at the base of the canyon. As you can see by the attached reprint link below (the paper is online but too big to send via DFO webmail), these features can be highly dynamic.
I was hoping you could make use of all the 1-hour current meter data we (DFO) collected in Barkley Canyon in the late 1990s in a collaborative project with UBC, and used/discussed by Allen et al. (2001) in some detail. I have the data (current velocity, temperature and salinity) but suspect that the data would add too much to your processing load, although they would provide good information on the seasonal background flows for your MSc.
I suspect that your proposed schedule is optimistic but Jody would know better if it is reasonable, especially during a pandemic. I wish you the best of luck with your course work.
Kindest regards
Rick
Thomson, R. E., & Spear, D. J. (2020). Gravity currents facilitate formation of high‐frequency internal solitons and bores at the base of the Fraser Delta in the southern Strait of Georgia. Journal of Geophysical Research: Oceans, 125, e2020JC016589. https://doi.org/10.1029/2020JC016589; Received 7 JUL 2020; Accepted 29 SEP 2020; Accepted article online 4
Hi Kurtis,
I also read through it and will pass on edits (review) and comments in a word.doc.
And I also think this is a really good start! It is hard time to be a student.
Since Rick has given such a nice overview, I will pursue some details.
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You've listed it as optional but I think it may be a very valuable component to do an analysis of critical slope. I think we have all the data in hand at ONC to provide a physical slope map based on some sort of smoothed resolution and a range of incoming wave directions. You can then pick a seasonal buoyancy frequency and probably more importantly a direction of incoming wave - so yes this could get messy very quick. But I think knowing the possible source areas would add a lot of insight into the single deployment site.
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I think you should look at the rotary spectrograms with a little more frequency resolution. It will make it easier to confirm that the analysis is correct, and also provide more information on currents that are likely from internal waves. Also I think you are correct, the flattening of the spectra at high frequency is indicating noise, and then you are whitening the white, which makes it hard to see what is going on in the tidal and inertial frequencies.
I think, and this could be discussed at an upcoming meeting, that you may need to focus on certain aspects of your proposal. The best way to pick those aspects, is let the data lead you - follow what shows up the most interestingly and clearly in the data. Often a spectrogram can show you that. For example, is there inertial energy? Is it modulated seasonally? As Rick asks, how much of a blue shift is there, is there a variety of blue shifts and there is episodicity in these blue shifts, or is it just a barrage of near-inertial energy.
Looking forward to having a meeting and discussing further with your committee, and particularly with your supervisor on how best I can guide you to achieve your goals. You've done really well in getting a handle on some of these techniques.
Talks soon, Steve