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Ice Tethered Profiler (ITP) Moorings. WHOI Principle Investigators John Toole Rick Krishfield Andrey Proshutinsky. Ice-Based Observatories. Goal: Document/understand interannual change through sustained observations of the Arctic ice pack, the overlying atmosphere,
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Ice Tethered Profiler (ITP)Moorings WHOI Principle Investigators John Toole Rick Krishfield Andrey Proshutinsky
Ice-Based Observatories Goal: Document/understand interannual change through sustained observations of the Arctic ice pack, the overlying atmosphere, and the upper ocean water properties
System Specifications • Capable of returning in real time, high accuracy daily (or semi daily) temperature and salinity profiles to 750m depth for 2 years. • Deployable from light aircraft and/or helicopters through a conventional 10.5” (.26 m) ice-augured hole. • Modestly priced, allowing them to be deployed in large numbers and be considered expendable. • Capable of supporting plug-in modules for additional surface and/or subsurface instrumentation.
Ice-Tethered Profiler Schematic Profiling Interval: 10m - 800 m or less Profiling range: 1,500,000 m Duration: 2.5- 3 years at one profile / day Temperature specification: -35° C Data telemetry: up to 50 kbytes / day Sensors: Seabird 41-CP CTD (same as ARGO floats) Telemetry: Seabird inductive link from profiler to surface unit; Iridium link to shore Power: lithium “DD” battery packs Size: Profiler fits through an 10.5” hole in the ice Profile speed: .2 meters/sec. (2 hours RT)
ITP Sensor Payload Options • CTD • DO – Dissolved Oxygen • MAVS – Modular Acoustic Velocity Sensor • Biohead – PAR Sensor, Fluorometer
Clamp on Inductive Instruments • SAMI - PH • SAMI (CO2) – CTD and PAR • Microcat
Finding an Ice Floe • Multi year preferred 1.5 – 4.5 meters thick. • Medium height ice ridges surrounding the site for protection • Few cracks. • If a suitable ice floe can’t be located, ITP system can be deployed in open water.
ITP 36 Deployed 08/29/2009 at 79 12.7N, 125 42.3E on NABOS cruise. Found in Iceland 2/2012
Double-diffusive Staircase Stratification Expanded views of the potential temperature profiles and potential temperature - salinity diagrams. Above the Atlantic Layer, temperature and salinity both decrease with height: a stratification subject to the diffusive layering form of double diffusion that is manifested by the staircase profile resolved by the ITP (left). Over plotted potential temperature-salinity curves at the level of the Atlantic Layer (right) clearly document intrusions that erode this warm salty water mass.
The End Thank You