Dispatch 11: Ice Station Three     Print

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Fred Marin

September 22, 2019

Location: 79° 00’ N 150° 08’ W

Sea Conditions: 3872m water depth; sunny, light breeze, extensive ice coverage, long leads.

Being adaptable doesn’t always mean we are trading down from an ideal situation, sometimes it allows us to get what we really want.  In this case, being adaptable granted us a third ice station for our final Ice-Tethered Profiler (ITP) deployment.  This deployment was originally planned to occur in open water and we now have the ideal situation where we will deploy the instrument in the ice, as it should be. 

We have now moved west and a little south from our last two ice stations, and the floes are not as thick as they were before.  So, locating an ice floe suitable for the establishment of an ice station was a noticeable process.  Locating such a floe sounds relatively simple, but in all reality, it requires a lot of skill, knowledge, and even more experience.  

How do we decide where to set up our ice stations? First, the scientists consult the ships ice observer, who shares data about the ice that is in the area and where the best floes would be for supporting an ice station.  Next, good old fashion binoculars are used to visually verify what is seen on the ships radar.  Once upon an ice floe of choice, the ice undergoes a closer visual inspection.  A smooth surface is ideal as it is indicative of a single, intact sheet of ice of the same history.  Ridges in the ice suggest that it has rifted and fractured making the floe to be less than ideal for establishing a station.  If all looks good, the ship then drives into the ice at a moderate speed.  If the ice doesn’t form long fractures across the sheet, and it also stops the ship; those are two indications that the ice is thick and strong enough for a station.  The final verification step is to send a team over the rail and onto the ice in the “man basket” (a cage for moving people with the crane) to drill holes assessing the quality of the ice.  Sometimes layers of ice sandwich water from melted ponds that form during the summer months.  Hard ice of about 1m in thickness is ideal for Ice Tethered Profiler (ITP) deployments.  Following this procedural dichotomy for parking a ship into a sheet of ice, we settled into a nice floe and set up shop for the day.

The day happened to be sunny, about -10° Celsius (14° F), with a light breeze.  It was a gloriously beautiful day on the ice! Getting our equipment and ourselves situated felt almost routine, and everyone was having a grand time completing their list of tasks.  We installed our last ITP without a hitch and packed up our gear.  Kazu Tateyama (Kitami Institute of Technology), and his team completed a third ice transect.  They measured ice thickness, and snow coverage, as well as collected samples for physical, chemical, and biological characterization of the ice floe.