March 2003 deployment of the Autonomous Ocean Flux Buoy at the North Pole EnviromentalObservation Station

The second NPS Autonomous Ocean Flux BUoy was deployed during late April 2003 as part of the North Pole Environmental Observatory. The following photographs and brief descriptions summarize the sequence of events leading to the deployment of the flux buoy at the very remote Arctic site near the North Pole.

[Hawker cargo plane and MI8 helicopter at the Borneo runway]

Getting there

All gear and personnel were flown North from a staging area at Resolute Bay, NT, Canada, through Alert to Ice Camp Borneo on a chartered Hawker Siddley 748 run by First Air. The 2003 deployment was made more complicated by the 6 km distance between Ice Camp Borneo and the runway. Equipment had to be ferried to the ice camp and remote deployment sites via Russion MI8 helicopter.

Moving around the ice flow

The buoy and deployment gear were moved from the runway to the deployment site with a Russion tractor and sled. The tractor was brought to Borneo to aid in runway creation and maintainene. The buoy site was chosen after a survey to find the oldest and thickest multi-year ice which had the best chance of surviving ice cracking and ridging (and destruction of the buoys). The ice flow will crack, form leads and ridge as it moves out of the central Arctic toward the Atlantic Ocean over the next year. The cluster of meterological, ice flux and ocean buoys was assembled over a four day period.

[Buoy deployment tripod, runway in background]

Mid-deployment of Flux buoy

The buoy was deployed aproximately 500 meters from the runway in 2.7 meter thick ice. Snow was scraped off the ice with the aid of the Russian tractor and a large power auger was used to drill an 11" hole through ice. The tripod was used to lower an instrumented frame through the ice, the top of which can just be seen in the ice hole. The next step is to attach the instrument frame to the bottom of the buoy housing.

Final Touches

With the buoy seated into the hole, the radome was attached and instrument cables coming up from the suspended instruments were connected to the internal electronics. The entire buoy deployment took aproximately 16 hours.

Testing the Buoy

With the buoy physically deployed, each component of the buoy system was checked with a laptop computer in the wind break tent. Weather was excellent, but the tent still provided important shelter to the buoy group out on the ice away from the main camp. In the background, a group of tourist skiiers can be seen.
The full data stream from the flux buoy is periodically sent back to the Naval Postgraduate School by an Iridium satelite modem, which also provides two way communication to diagnose problems and change setups in the instrument system. If the Iridium link fails, a shorter data message is sent back by the older Argos satellite system. A Global Positioning System located with these antennas provides accurate time and position measurements every 15 minutes. The antennas for these systems are enclosed by the orange and white radome at the top of the buoy.

The deployed flux buoy

The buoy assembly was completed with a radome cover over the antennas to reduce snow buildup and provide some protection from potentially destructive Arctic foxes which have an unusual interest in our instrument systems. Measurments of ocean fluxes are made from an instrument cluster 4.5m below the ice within the 30-50m deep ocean mixed layer which sits above the strongly stratified halocline. A very low power acoustic travel time current sensor, a stable conductivity cell and a very high resolution thermistor measure velocities, salinity and temperature in the same small volume. Correlating fluctuations of vertical velocity with horizontal velocity fluctuations, temperature fluctuations and salinity fluctuations provide estimates of the vertical transport of momentum, heat and salt through the ocean mixed layer (see for example, McPhee and Stanton, Turbulence in the statically unstable oceanic boundary layer under Arctic leads, Journal of geophysical Research, pp6409-6428, March 1996).