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Glider design goals. Resolve scales O(1-10 km), O(hours-weeks) Describe domains O(100 km) square for months ~ ½ kt @ ~ ½ W ► ~ 4000 km, 7+ months Flexible deployment, large ships not required Near real time data & control globally Extended (many months), unattended operation Reusable
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Glider design goals • Resolve scales O(1-10 km), O(hours-weeks) • Describe domains O(100 km) square for months ~½ kt @ ~½ W ►~4000 km, 7+ months • Flexible deployment, large ships not required • Near real time data & control globally • Extended (many months), unattended operation • Reusable • Surveys and repeat sections (boundary currents, trans-basin segments, straits, synoptic boxes) • Virtual moorings • Feature chasers (roam / inspect / follow)
University of Washington Seaglider • Surface to 1000 m. • Horizontal speed 0.1 - 0.45 m/s (~22 km or 12 nm per day @0.25 m/s) • Vertical speed 0.06 m/s (minimum) • Buoyancy range ~840 g • 5 kg/m3 density range ►250 g • Endurance depends on ambient stratification, dive depth and desired speed • Longest range to date: 3900 km • Longest endurance to date: 31 weeks • Under Development • Aanderaa Optode • RAFOS navigation • Altimeter & Ice Draft • Inferred • Depth-Averaged Current • Surface Current • Vertical Current Profile (|w|>0.5 cm/s) • Sensors • SBE Conductivity/Temperature • SBE 43 Dissolved Oxygen • WETLABS BB2SF- Chlorophyll a Fluorescence, Optical Backscatter (red & blue)
Handling • Hull length: 1.8 m • Wing span: 1.0 m • Mass: 52 kg • Easy to deploy and recover- RIBs, fishing boats, research vessels, aircraft (?). • Hand-launch and recover from small boats • Crane launch from larger vessels • Pole-and-lasso or recovery from large vessels • Use small boats from larger vessels when possible
Seaglider Operations August 2003 to present Lofoten Basin, 18 June 05 • Over 5 Seaglider-years of operation • Fjord, continental shelf, open ocean • 19-57° latitude range • Boundary currents: W. Greenland, Labrador, California, Alaska, Kuroshio • Weather & seas: Many severe winter storms & Typhoon Tokage
Washington Coast Repeat Surveys • Nearly continuous presence August 2003 to present (approaching 2 years) • Mission durations typically 4 – 5 months • Deploy and recover at shelf edge from small, chartered fishing vessels • Seasonal/inter-annual variability and Seaglider testbed
Gulf of Alaska (Northeast Pacific GLOBEC) • Surveys of Alaska Stream and eddies • Mission lengths 4 – 5 months • Deploy and recover from chartered fishing vessel • Satellite altimetry guides glider repeatedly across translating eddy • Attempted surveys in Alaska Coastal Current- shallow water, surface velocities 1.0 – 1.5 m/s, depth average 0.5 m/s
Wintertime Labrador Sea October 2003 – February 2004 September 2004 – March 2005 Longest Seaglider mission: 31 weeks
Control and Display • Iridium modems call directly to modem banks on shore (base stations and modems can be relocated as needed) • Linux base stations receive and process data • Commands issued through simple text files downloaded during each exchange • Limited automated parsing or error checking of commands, waypoints or other directives • Web-based display for data presentation, diagnostics and alerts. Includes auxiliary data (satellite images, meteorological forecasts, etc.). Examples: • GINA: http://seaglider.washington.edu/gina • IOP Glider Operations: http://iop.apl.washington.edu/seaglider/ops.html
Ongoing Glider Developments • Seaglider “ER” (+33% range +50% samples) • Vehicles currently in production • Deepglider (6000 m depth capability) • Prototype tank testing this week (15 June 2005) • Extended under-ice operations using acoustic navigation (initial use in Davis Strait) • Navigation tests in North Pacific (NPAL) and Lofoten Basin (Norwegian Atlantic Current, June – October 2005) • Aanderaa Optode (dissolved oxygen) and evaluation of SBE and Aanderaa sensors • Testing at Hawaiian Ocean Timeseries (HOT) site • Now in a choice of 3 colors…