APLIS POSTCARD #8
19 March 2007
Greetings from APLIS, adrift in the Arctic Ocean.†
As I said yesterday, the ice is nearly constantly in motion.† Overall, in this region of the Beaufort Sea, we expect to move west or northwest.† But that doesnít mean that motion is always in that direction.† During the first 2 weeks of camp buildup, the floe on which APLIS is located oscillated east-west along a line about 20 nm wide.† At any given time, motion is based on winds acting over hundreds of square miles of ice, currents, and residual motion from previous days.† The most important thing to keep in mind is that we have absolutely no control over where we go.
Today Iíll talk about some of the science work that weíre doing here.
We have two graduate students from the Naval Postgraduate School in Monterrey, CA here at APLIS doing thesis research.† LT John Bleidorn and LT Tim McGeehan are making use of our location on the ice to study under-ice oceanography.† Iíll let them explain the experiment for themselves.
We will be using sonar to image an underwater ice keel and then measure the turbulent wake behind it.† We hope this data will improve models which describe the complex interactions between the atmosphere, sea ice, and ocean.
To get their instruments in the water, they found a location that appeared to be adjacent to an ice keel.† When the ice deforms into ridges, there is a corresponding above-ice feature, or ridge.† Just outside camp was just such a ridge so they set up their study area on the flat ice adjacent to the ridge and started melting a hole.
NPS Tent and their Ice Ridge
We intentionally chose to locate our camp on a floe thatís several years old - older means thicker and more stable.† But it also means that, after a couple summers of surface melting and years of being exposed to the erosive effects of the wind, ridges can be worn down while the keels beeath them survive.
Thatís what happened here.† After two days of melting, they finally broke through to the ocean - through 40 feet of ice!† They didnít melt next to the keel, they melted through it.† Anyway, today they are starting to install their instrumentation.† Iíll provide some of the results as they come in.
But thatís not the only science that weíre doing.† Iíve mentioned before that weíre going to turn the camp over to the National Science Foundation after weíre done with our work.† The major thrust of that camp will be to study various aspects of ice mechanics.† They have asked if we could install some of their instruments during our camp in order to monitor the movement and evolution of ice in our area.† Their highest priority is for us to install a ring of instruments circling the camp at a radius of about 6 nm.† Weíve wanted to install these before now but the helicopter has been tied up with four straight days of surfacings.
Today we finally had our chance.† Randy Ray (our ubiquitous Field Operations Coordinator), assisted by Doug Anderson (from ASL) and LtCdr Stuart Capes (one of our RSOs) set out this afternoon and got all 6 buoys installed in just a couple hours.† Hereís what they look like.
Randy Ray and Stuart Capes Installing a GPS Buoy
In the first postcard, I said that Iíd talk about our furry neighbors but you may have noticed that I havenít mentioned them so far.† Thereís a reason for that - we havenít seen any.† At least, until yesterday.† On their way back to Prudhoe Bay yesterday afternoon, the VIPs spotted a mother and cub, about 100 miles to the south, headed this way.† Only a matter of time now.
Arctic Submarine Laboratory