Call minutes – Inner Shelf DRI ship ops (May/05/2017 and May/16/2017)

Soliton chasing module (8-12 h, nighttime):

• Data from the Pilot experiment: High-frequency IWs dissipate at ~15-30 m, signal is very messy and weak around the rocky outcrop, but could still make out some of it. Between 50 m and 30 m, signal of the packet was clear.

• If Biosonics echosounders are not available, may use ADCP backscatter for seeing high-freq IWs and their bores.

• Also use data from the moorings to help interpret the shipboard data after the IOP.

• Rule of thumb: Solitons take ~8-12 h to go from 100 m to 20 m isobath. Faster if N² is higher.

• Compare Oceano Beach (~straight) with Pt. Sal/Mussel Rock (crooked): Do we observe refraction of the IW packets?

Meso/submesoscale module (36-48 h):

• Jack: Use 2+ ships to beat down time aliasing. Test scenarios with model sampling to decide.

• Prior ro IOP: Work with Manu to get an idea of the large-scale picture we should expect (e.g., are there upwelling/downwelling fronts, but more generally, what might the cross-shelf density gradient look like).

• Prior to IOP: Look at SST images (MUR composites and AVHRR).

• Coordinate with Jim L. to have the Kalipi parallel to the Sproul on the ~10 m for some time.

• Overview for the Sproul: Blocks of 36 h occupations of the box are ideal, can work around that. The more blocks that can be completed the better.

• Prior the IOP: Choose from a set of pre-defined boxes, depending on the large-scale forecast. For example, if there’s a strong coastal upwelling or wind relaxation event happening, we can coordinate to capture the largest cross-shelf gradients.

Headland eddies module (24-36 h):

• Interesting questions: What is the vorticity production associated with the subtidal mean flow and the tidal flow? What form of instability (centrifugal, symmetric, shear) is associated with their decay? Teaming up with the drifter group will be very helpful for this.

• Can be done in one 24-36 hour module. Perhaps during two daytime drifter release periods.

• Small boat sampling in a repeat pattern over a tidal cycle in the nearshore of the point (or whatever portion of the tidal cycle a small boat is there for).

• Larger vessel repeat sections (box or butterfly) on larger scales, in deeper water.

• Drifter releases at or upstream of the headland, perhaps multiple times, while vessels sample around them.

• Aircraft images of wake snapshots?

• See Jen’s email and Palau cruise report for details.

TODO and comments:

• Jim M.: Ask Manu for total (barotropic + baroclinic) surface and bottom model pressure fields.

• Kalipi (small boat) will be based in Avila Beach. Transit speed ~20 kt with good weather (~2 h to Pt. Sal).

• John’s guess: 5 days should be enough for deploying all moorings.