Gliders science

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• Gliders- science current developments
• Arctic Navigation and Telemetry

Craig M. Lee Applied Physics Laboratory,
University of Washington craig_at_apl.washington.edu
http//iop.apl.washington.edu
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Autonomous, Telemetering Profiling Vehicle

• Surface to 1000 m.
• Glide slopes from 14 to 32.
• Horizontal speed 0.25 m/s (22 km/day)
• Vertical speed 0.07 m/s (minimum).
• Target 2,000 km (vertical) and 10,000 km
  (horizontal) per mission.
• Strain gauge pressure.
• Seabird temperature, conductivity and dissolved
  oxygen (free-flow).
• Depth-averaged flow (predicted-actual position).
• Vertical velocity (predicted-actual vertical
  speed).
• Vertical resolution 0.51.0 m.

• Hull length 1.8 m
• Wing span 1.0 m
• Mass 52 kg
• Easy to deploy and recover- RIBs, fishing boats,
  research vessels, aircraft (?).

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Eriksen Rhines
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Glider Developments

• Deployments exceeding 5 months off Washington
  Coast (Eriksen and Lee) and Gulf of Alaska (Lee
  and Eriksen).
• Two gliders over-wintered in Labrador Sea
  (Eriksen and Rhines). Missions 4 months, both
  vehicles lost (one found on Disko Island!).
• Currently Washington coast, Gulf of Alaska,
  Labrador Sea (2), East China Sea, North Pacific
  (2).
• Two groups working together to field 7 vehicles
  in 3 colors, 180 degrees of longitude, two
  oceans. All deployments executed within 2-month
  time frame.

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Glider Acoustic Navigation

• Two gliders in North Pacific equipped with 260 Hz
  RAFOS receivers. Ranging on sources located off
  California coast (2000 km range). Tests of 780 Hz
  sources and (moored) receivers in Davis Strait.
  Ranging at 100 km.
• Year-long 780 Hz acoustic propagation experiment
  underway in Davis Strait. Attenuation as a
  function of ice cover and stratification. Two
  sources, six receivers, two depths, ranges 0
  200 km.
• Two gliders off Norwegian coast (collaboration
  with E. Hansen, NPI). Navigation in JC Gascard
  RAFOS field. April June 2005.

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Arctic Navigation and Telemetry

• Long-range Navigation (basin scales)
  Low-frequency (20 Hz). Small numbers, large and
  costly.
• Medium-range Navigation (O(100 km)) 200-1000 Hz,
  encoded position. Moorings and ice tethered
  platforms, homing.
• High-bandwidth Communications 15-30 kHz, ranges
  of a few kilometers. Data transfer, carried by
  all platforms.

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• International Arctic-Subarctic Ocean Flux (ASOF)
  program
• SEARCH
• NSF Freshwater Inititiative

• Ocean Observing Components
• Arctic Ocean (Steele)
• Northern Straits (Falkner, Melling, Munchow,
  Prinsenberg and colleagues)
• Hudson Strait (Straneo, Pickart)
• Labrador Sea (Eriksen, Rhines)
• Davis Strait (Lee, Gobat, Moritz, Petrie)
• Hydrological cycle Atmospheric, Terrestrial,
  Riverine, Impacts

Prinsenberg (BIO)

• By monitoring CAA inflows/outflows and
  coordinating with other FWI efforts, can we
  reconcile ocean fluxes with terrestrial and
  atmospheric inputs?
• Relative importance of freshwater exchange
  processes with the North Atlantic? How does this
  vary at seasonal and interannual time scales?

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Challenges

• Magnetic North Pole nearby
• Ice bridges and ice bergs
• Measurements over shallow, ice-threatened
  shelves.
• Strong tidal currents ( 1 m/s)
• Small internal Rossby radii
• Ice and water contributions
• Quantify critical near-surface regime in the
  presence of seasonal ice cover
• Canadian Greenland native community concerns
• Year-round measurements
• Cost-effective long-term (decades) measurements.

June 3, 1998 AVHRR
Falkner, Melling, Lee
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Falkner, Melling, Lee
Falkner, Melling, Munchow