Monthly Archives: May 2017

Ship ops teleconference notes – May/26/2017

Call minutes – Inner Shelf DRI ship ops (May/26/2017)

Attendees: Amy Waterhouse, Jen MacKinnon, André Palóczy, Jim Lerczak, Kate Adams, John Colosi.

Soliton chasing module comments:

  • The purpose of the longer line in the IW chasing document is to get a sense of deep to shallow transition.

  • Jim L.: We need to think about the spacing between ships chasing the IW fronts. What is the along-shelf coherence scale of the NLIWs and bores?

  • John: Are ship-based measurements of TKE dissipation more accurate than from moorings? Jen: Yes.

  • Jen, André: IW chasing cross-shelf lines will also produce useful data for the large-scale variability (e.g., vorticity, divergence, strain, dissipation).

General remarks:

  • John: Might have 2-3 days to spare at the end of mooring deployment period for surveying.

  • Jim L.: Kalipi will be available for ~10 h daily, return to Avila Beach early. Watch out for Santa Ana winds.

  • Jim L.: Will ship gear and Kalipi to a small facility on Avila Beach owned by Cal Poly.

  • Jim M.: Will help set up Hans Graber’s radar on the Oceanus.

  • Bottom is silty/sandy offshore of the ~30 m isobath, rocky around Pt. Sal and sandy elsewhere.

TODO:

  • André: Do ship sampling of model outputs (code is working, need higher-frequency model outputs to sample).

  • André: Write meso-/submesoscale module document.

  • John C.: Contact aircraft group (Ken, Luc, Chris C. and Gordon F.) asking about their plans (DONE, waiting for reply).

  • John C.: Contact radar group (Eric T. and Tony) asking about the X-band radar on the Ride (DONE, Eric will follow up by email next week).

  • Jim L.: Make simplified spreadsheet with schedules of the 4 vessels (overlapping periods, etc).

Ship ops teleconference notes – May/05/2017 and May/16/2017

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.

Teleconference notes, 3 May 2017

Inner Shefl DRI Monthly Meeting 2017-05-03

attendees: Chris Chickadel, Melissa Moulton, Joe Calantoni, Ed Braithwaite, Ata Suanda, Luc Lenain, Andy Moore, Amy Waterhouse, David Honegger, Manu Di Lorenzo, Tony de Paolo, Art Miller, Chris Edwards, Jack Barth, Jen MacKinnon, John Colosi, Will Crawford, Jim Moum, Johannes Becherer, André Palóczy, Nirnimesh Kumar, Will Crawford, Reggie Beach

Agenda
Ship IOP ops overview/discussion
Modeling update from GA Tech.
Asset position reporting (MTS)
Ship IOP ops
– 4 vessels (Sally Ride, Sproul, Oceanus) + small vessels
OSU small boat timing plans: 8-18 Sept, 9-16 Oct
– surveys in space for fluxes, onshore propagation of internal SW
only 4-5 days with all vessels (12-16 Sept)
maximize number of sampling vessels for the phenomenon in question (multiple synoptic gradients)
coordinating aircraft and drifter deployments
synoptic surveys near mooring arrays 10-70m depth
use model to analyze actual survey patterns
large scale survey in evenings (boundary conditions for modeling, microstructure)
Oct, only 2 vessels
– Ship Plan expected in about 1 month
– headland areas
– recognize south, landbased radar coverage
– drifter integration?

Modeling
– ongoing forward modeling, from 3km down to 22m North grid almost completed (all available except for 22m grid coupled to wave model on the scrips modeling blog, check there)
– Discussing experimental forecast for the fall field work, question to the group: how useful given computational expense?
Generally seen as very useful, 66m N, 200m grid would be adequate for ops planning
200 m L3 grid would be very useful for use on the UNOLS vessels, cross-shelf density gradient
How accurate? Will verify 2009 runs with data to assess, Ata has some collected data for validation
– Inverse modeling for flow field stability analysis
– Diagnosing adjoint sensitivity analysis

Ship ops teleconference notes – April/26/2017

Call minutes – Inner Shelf DRI ship ops (April/26/2017)

Ride:

  • 3-4 kt, fishing reel with microstructure profiler, bow chain with RBR Solos/Concertos and side-mounted ADCP.

  • Sep/17-19: Overlap with Sproul.

Sproul:

  • 4 kt, bow chain, SADCP (maybe a side-mounted ADCP), fishing reel/winch (possibly borrow one of J. Nash’s) with towed body (an RBR Concerto, or Drew Lucas’ RBR with chl-a fluorometer and O2 sensor, other options).

  • Being under the HF/X-band radars’ footprints would be ideal. Consider this when choosing the sampling box.

  • Sep/17-19: Overlap with Ride.

Oceanus:

  • Survey mostly on the inner shelf, 15 m – 30/50 m.

  • Will do deep CTD casts during deep buoy deployments to provide hydrographic background.

  • 4-5 kt, ADCPs + towed vehicles.

Kalipi/other small boats:

  • Can survey up to the ~10 m isobath.

  • ADCP. 1200 kHz (high res) or 600 kHz (full-depth coverage).

  • Backup RBR with 6 Hz CTD + OBS.

  • 12 h ops, ~10 h of science time.

  • Plan to depart very early to return before late afternoon.

Other remarks:

  • Wil have periods with 2 vessels and periods with 4 vessels. Coordinate the science goals accordingly.

  • Coordinate surveys in 36-48 h modules. Will average out some of the tidal variability, but still be fast enough to avoid important changes in the wind forcing.

  • Amy: Quad-copter with infra-red camera may be available.

  • Jack: Idea for multi-vessel period: Occupy 2 or 3 boxes simultaneously. One north of Pt. Sal (in the OB area), one south of Pt. Sal and one centered on Pt. Sal.

  • Jen: Idea for soliton chasing surveys: What is the along-shelf coherence scale of the packet? Follow the same wave front with 2, 3 or 4 ships simultaneously.

Next steps:

  • Sproul, Ride, Oceanus and small boat groups should provide preliminary sampling coordinates to sample the ROMS outputs and compare with the ROMS instantaneous fields. This will help assess the degree of time aliasing we should expect in the field.

  • Amy created a shared Google doc for the ship ops. Each group will update it as new details are defined.

  • Touch base at the Munk Symposium (May/15-18 at SIO).

scripps oceanography uc san diego