Closed kurtisanstey closed 2 years ago
All:
All (zoomed):
Time averaged:
Time averaged (zoomed):
Question for @jklymak: How do I best approach discussing the offset Axis data for 2013 and 2014, in relation to the plot below (made from blue and yellow periods - red omitted):
@kurtisanstey I guess this is probably a factor of 3 beam solutions having more variance than 4-beam solutions if the velocity field loses correlation on the scale of the beam separation. So, its not as big a problem at lower frequencies, because the lateral scale of those motions is large. However, at near-N, the lateral scale approaches the vertical scale and each beam can see quite different velocities. A 4-beam solution will average that out over the horizontal pattern. A 3-Beam solution will not average as much. Further the 3-beam solution will have some preference in what it is looking at, given the direction of the three beams.
Todo: - check the orientation of the beams compared to the canyon and see if that story is consistent.
Overall I'm not sure what we can do about this - I think the shoulder is still significant and useful to look at. We should just be careful about explaining the limitations.
Axis site:
Magnetic compass heading:
Offset heading:
Magnetic compass + offset heading:
Shoulder-dissipation fits:
@jklymak
See previous comment for updates.
Sorry, which alignment corresponds to your red, yellow, and blue periods, as circled in the integrated variance plot above?
@jklymak on each page, the top alignment is for the first half of the blue period, the centre alignment is for the second half of the blue period to the end of the red period, and the bottom alignment is for the yellow period.
The first page is based on the compass heading, the second page is offset heading, and the third page is them combined (I am assuming this is the correct one).
I don't understand the addition in the third sheet. Why are there two such large numbers? The compass should give you the heading of beam 3. The only thing you need to know after that is if that heading has the magnetic declination of 20 degrees or so included in the heading or not. (i.e. the north pole and the magnetic pole are 20 degrees apart at our position on the earth).
But anyways, I think the point is that for the two deployments with higher variance they were only 20 degrees off from each other, so it would need to be a pretty asymmetric wave field to give such a large difference. I think we can mention this possibility, and discuss it as possible future work, but outside our scope here. To make sense of it you would have to go back to the raw data and process 2-beam solutions, and that is more work than seems necessary.
Thanks @jklymak! Very helpful. I'm also confused about the two large numbers; I was surprised to find the offset heading listed somewhere obscure after already looking at the compass heading.
Archived for reference.
There are no velocity events upward of 1 m/s (or even close to that) that would indicate solitons, at either site.