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Project Title: |
Mechanisms Responsible for Mesoscale Eddy Energy Dissipation |
Project Status: |
Submitted |
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Principal Investigator: |
Eleanor Frajka-Williams, UoS |
Project Institution: |
UoS |
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Project ID: |
105845 |
Version #: |
3 |
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Date Submitted: |
7/27/2017 9:24:00 AM |
Created By: |
Eleanor Frajka-Williams |
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Date Last Modified: |
12/18/2018 12:10:00 PM |
URI Serial #: |
None |
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Funding Agencies: |
OTHER - NE/N001745/1 - Funded |
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Summary of Field Work: |
Mesoscale eddies-swirling vortices of water 100-200 km across-are ubiquitous in the world oceans. They are highly energetic, and act to redistribute energy and properties. While eddies are present in all ocean basins, they disappear from satellite altimetry preferentially at western boundaries. Understanding how and why eddies lose energy is critical to our understanding of large-scale ocean dynamics and their representation in climate models. The mechanism(s) responsible for this disappearance---radiating energy away, contributing energy to the mean flow or dissipating locally---are not well known, and different mechanisms will have different effects on circulation. We propose to construct the first detailed map of eddy energy and dissipation at the western boundary, in order to better understand the mechanisms responsible for eddy disappearance.
Specifically, our objectives are to:?
1. Map turbulent dissipation in the presence of an anticyclone and a cyclone;?
2. Quantify the evolution and decay of mesoscale eddy energy at the western boundary for an anticyclone and a cyclone;
3. Determine the characteristics of the dynamical phenomena associated with eddy dissipation;?
4. Determine importance of local dissipation to the energy budget of mesoscale eddies.
Our proposed region of study is at 26N at the western boundary of the Atlantic ocean. Moored instrumentation is being deployed through the UK RAPID moorings program, and gliders will be deployed in the 2017/18 year.
For 2017, we propose to deploy expendable current profilers (XCPs), a tethered microstructure profiler (VMP), and Seagliders including one equipped with microstructure sensors from a regional-class vessel to make finescale profiles of currents and water properties (<1-m) and microscale profiles of temperature and shear variance (<10-cm). These observations will be used to create a three-dimensional (3D) snapshot of turbulent dissipation, with concurrent velocity and density profiles, both at the peak and tail end of one anticyclone and one cyclone. These high resolution observations will be key to linking the patterns of dissipation with the flow field/topographic conditions in which they occur. |
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Summary of Facility Requirements: |
Sufficient deck space for two winches for the VMP 2000. Block or a-frame to handle it over the back.
Deck space for Seagliders and block/a-frame to deploy over the back.
Power for the winches (see notes under "summary of other requirements or comments")
Vessel mounted 75kHz ADCP
Echo sounder
Space to mount a 4-element direction antenna (very light weight) for the XCP radio receiver
We require a vessel capable of deploying the tethered Rockland VMP 2000, steaming at 1/4 knot to keep the lightweight tether clear of the vessel and the instrument. We will also deploy XCPs which need to be lowered over the side, the ship steams away 1-2 ship lengths, then waits in the same heading for the data to be transmitted by radio. We are bringing our own antenna and radio receiver (the antenna to be fixed to the vessel) and deck unit to receive and process the data.
Vessel-mounted ADCP (particularly 75kHz) will be used to survey the area, including the mesoscale eddy field, in order to determine where the high current speeds are relative to topography. The ship echo sounder will be used to decide how deep to profile with the VMP, in order to avoid hitting the bottom. |
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Summary of other requirements and comments: |
The VMP winch takes 415V, 3 phase power.
It may be worth a second discussion regarding how to adapt the winches to the Walton Smith power (208V, 3 phase) since there were some minor difficulties with this last year. |
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Type of Request: |
Primary Ship Use |
Request Status: |
Submitted |
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Request ID: |
1009460 |
Created By: |
Eleanor Frajka-Williams |
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Date Last Modified: |
1/26/2018 11:56:00 AM |
Date Submitted: |
7/27/2017 9:24:00 AM |
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Year: |
2017
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Ship/Facility: |
F. G. Walton Smith
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Optimum Start Date:
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3/1/2017 |
Dates to Avoid: |
9 days |
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Earliest Start Date: |
2/19/2018 |
Multi-Ship Op: |
No |
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Latest Start Date: |
3/25/2018 |
Other Ship(s): |
n/a |
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Operating Days Needed: |
Science Days |
Mob Days |
De-Mob Days |
Estimated Transit Days |
Total Days |
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7 |
2 |
1 |
2 |
12 |
Repeating Cruise?
(within same year) |
No |
Interval: |
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# of Cruises: |
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Description of Repeating cruise requirements: |
n/a |
Justification/Explanation for ship choice, dates,
conflicts, number of days & multi-ship operations: |
n/a |
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Short Description of Op Area
for use in schedules: |
East of Abaco |
| Description of Op Area: |
East of Abaco, Bahamas between the continental shelf edge (about 400m water depth) and the deep water (4000m). |
| Op Area Size/Dia.: |
80 nautical miles x 60 nautical miles |
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Lat/Long |
Marsden Grid |
Navy Op Area |
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Beginning
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Ending
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Show Degrees Minutes |
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Foreign Clearance Required? |
Yes |
Coastal States:
Bahamas |
 Important Info on Foreign Research Clearances
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Are you or any member in your science party bringing in any science equipment items which are regulated for export by the International Traffic in Arms Regulations (ITAR) and/or the Export Administration Regulations (EAR)?
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No |
If yes, have you applied for the necessary permits through your export control office?
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No |
| Questions about ITAR/EAR regulations?
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Comments about foreign clearance requirements or
description of any other special permitting requirements
(e.g., MMPA, ESA, IHA, Marine Sanctuaries, etc.) |
Bahamas clearance needed, no samples to be taken. |
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Requested Start Port |
Intermediate Port(s) |
Requested End Port |
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Miami, FL, USA |
None |
Miami, FL, USA |
Explanation/justification for requested
ports and dates of intermediate stops
or to list additional port stops |
Walton Smith home port. |
Important Info on Working in Foreign Ports
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Chief Scientist: |
Dafydd G. Evans, UoS |
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# in Science Party |
8 |
# of different science teams |
1 |
# Marine Technicians to be
provided by ship operator:
(include in science party total)
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1 |
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Explanation of Science Party Requirements and Technician Requirements |
We will bring 3-4 technicians to support the Rockland VMP2000, and 4 science party to monitor the data, support the XCPs and microstructure glider deployments. |
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 Dynamic Positioning |  ADCP | Multibeam | Seismic |
| Dredging/Coring/Large Dia. Trawl Wire | Stern A-frame | Fiber Optic (.681) | 0.680 Coax Wire |
| SCUBA Diving | Radioisotope use - briefly describe | NO Radioisotope use/Natural level work | Other Operator Provided Inst. - Describe |
| 0 PI-Provided Vans - briefly describe | MOCNESS | | |
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Explain Instrumentation or Capability
requirements that could affect choice
of ship in scheduling. |
Rockland VMP-2000 tethered microstructure profiler and winch. This measures shear and temperature at 512 Hz, and has a winch with lightweight data cable/tether so that the profiler can freefall, and then be winched back in.
Lockheed Martin Sippican expendable current profiler (XCP). We are bringing the deck unit, antenna + VHF receiver, and all tools necessary to deploy.
In the case that the ship's 12 khz echosounder is operational, we may bring a pinger to help judge the height of the VMP above the bottom.
If available, we'd like to use the ship CTD for glider calibrations.
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Explain Major Ancillary Facilities
Requirements and list description
and provider for "other" systems. |
n/a |
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