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Dispatch 13: Deployments and Retrievals: ITPS & Moorings

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October 2 & 3 Photos
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Peter Lourie

October 2 & 3, 2016


Michiyo slept through Eggs Benedict on our first Sunday, so she didn’t let it happen again today.  Something she remembers fondly from a former trip on the Louis. 

The officers wear their whites on Sundays and move leisurely, dapperly, around the ship inspecting cabins and things. As someone put it on our first Sunday, “They make sure your cabin isn’t out of control.”  When I heard that I raced back to my cabin to tidy up and then walked down the corridor with an armful of laundry right past the neat-looking officers, including nurse Amelie.  Always smiling, Chief Mate Trevor called out, “You dropped a sock.”  And added, “Greatest fear of the crew is that they drop their underwear!!”   At least mine was only a sock.  But pretty embarrassing.

I’m thinking of my daughter, who today has just taken the one train a week from Rishikesh, India, to Kathmandu, Nepal, a twenty-hour ride, then another so many hours to Pokhara.  Not that I could do any rescue if she needed me even if I was in Vermont, but a father’s worries are here confined to the railings of a ship surrounded by ice.  I’d like to access the Web just to find to out how many universes distant is Kathmandu from our last CTD rosette cast or our next mooring recovery in the Beaufort.

ITP Buoy Into Water

Rick said that the ITP buoy we deployed yesterday into open water was only about the sixth such buoy Rick has done in water out of the 90 ITP’s he’s done altogether!  All the rest were on ice.  But the conditions this year are just not conducive to ice deployment, as we found out the other day, our one and only day on the ice for the entire trip.  As Rick says, it’s not ideal to put one of these into open water because when the ice starts to form around it, there’s more of a chance of ice ridges and ice layers knocking it about and possibly damaging some of the delicate equipment.  If, however, it’s put into already forming ice, there’s a better chance it’ll weather the winter.

Rick told me today more about why it was a disappointment that the profiler was missing from yesterday’s buoy.  It would have contained a lot of great information that was missing.  Apparently the buoy recovered yesterday was deployed two years ago from a South Korean ship (collaboration in oceanography between nations is important) in an area where other buoys hadn’t yet been deployed, so Rick and his team were excited about getting the data on the profiler. Normally the information collected on the profiler (that device that moves up and down the buoy line to take physical measurements at different depths) is sent to the top of the buoy and out by satellite to the scientists back home.  For some reason the information from this particular buoy had ceased broadcasting.  So Rick had hoped that the profiler itself, if found, would fill in the blanks.

When the buoy was recovered, the anchor was still fixed to the end of the line and there was great hope the profiler would be there, too, but it was disappointing when the anchor was pulled up without the profiler, which must have been dragged and got torn off at some point on the buoy’s circular journey through the Beaufort.

Mooring Recovery Success & Data Gold

Getting back the profiler off a Mooring (called McLane Moored Profiler (MMP)) seems to me like finding a kind of Data Gold.

Will Ostrom again goes fearlessly out and over the side in the basket on the winch worked by Kirby Vatcher and down to the waterline to latch onto the big yellow float that has been remotely released from the anchor.  Most of the day working in bitterly cold blowing snow, the buoy and mooring team and perhaps 8 crew work it out of the water.  Jeff and Cory and Rick finally walk away with profilers, upper and lower ones on the 3000 meter line.  They’re walking with data gold in their hands. Again, I’m amazed at the efficiency of these guys.  Down in the hold, Jeff O’Brien carefully takes out the 2 Gig Compact Flash card, plugs it into his computer and finds all the data for a full year stored there and waiting to be analyzed.   Eureka.  Beaufort Gold.

And today they will redeploy the Mooring while the snow keeps blowing harder.  The men will work steadily through the Arctic wind and bitter cold.  And Chief Mate Trevor and Bosun Bill will again be there to coordinate with the bridge. Tomorrow we head south.

From Methods

Moorings provide time series of temperature, salinity, currents, sea ice draft, and bottom pressure (sea surface heights). A McLane Moored Profiler (MMP, colored yellow in mooring diagram) is used to sample currents and hydrographic data from 50 to 2050 m with a 17 hour time interval. In addition, an upward-looking sonar (ULS) provides information about sea ice draft, and a bottom pressure recorder (BPR) measures sea level height variability and near bottom temperature and salinity. Each mooring consists of a surface flotation package at 50 m depth housing an ULS, a mooring cable containing the MMP, dual acoustic releases and tether to BPR attached to the anchor. 




McLane Moored Profiler (MMP)The MMP is an autonomous, instrumented platform on a conventional mooring tether, which repeatedly traverses that line based on a user defined operation program, acquiring in situ profiles of temperature, salinity and velocity. The maximum depth rating is 6000 m, and design endurance is over one million meters per deployment. The system software gives the operator great flexibility in defining the sampling schedule, allowing profiles to be interspersed with extended measurements at fixed levels. The CTD and current measurement instruments presently employed on the MMP are products of Falmouth Scientific, Inc. 

To learn more about Peter Lourie click here.



Last updated: September 13, 2017
 


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