Alice and I have now been on the Louis S. St. Laurent for 2 weeks. During this time we have traversed much of the southern Beaufort Sea, and right now we are steaming due north hoping to achieve 150W 80N. We are at 77.5N now, and well on our way. The ice has been thin and the Louis is making steady progress at 12 to 13 knots. It is very impressive to watch how the ship cuts through the ice like butter at these speeds!
Martin, thank you very much for your question regarding our goals on this cruise. You may know that I attended the same cruise last summer. Last year our primary objective was to deploy 6 buoys in a cluster that will monitor ice deformation. These were deployed around a cluster of other buoys to make up an Ice Based Observatory, which automatically monitors thermodynamic and dynamic changes in the ice pack, ocean currents and the top 300m of ocean water masses. Our part of this collaborative effort is funded by the National Science Foundation, to investigate the effect of sub-diurnal ice motion on the sea ice mass balance. We believe that inertial motion of the ice-ocean surface layer and tides might have a significant impact on the thickness of sea ice by increasing lead and ridging activity. Bill Hibler and Andrew Roberts have developed a model of this phenomena, and the buoy data will be used to validate this model. This year I am deploying another cluster of buoys.
In support of the buoy experiment Alice and I are making hourly ice observations during the cruise. This provides a great deal of information that can not be obtained directly from satellite data during the summer. For example, we are recording the type of ice we travel through, how dense the ice pack is and what the mean thickness of the ice is. Last year this information proved very useful to identify why ice conditions were so unusual in the Beaufort Sea during late summer. I am repeating ice observations this year, as with two years of observations, buoy and satellite data, we can track the motion of particular ice regions. We are interested in how ice moves around the Beaufort Gyre, and how ice is entrained from the Chukchi Sea and high Arctic north of the Canadian Archipelago. The origin of ice influences the thickness and age characteristics of the ice in the Beaufort Sea. We hypothesis that recent low ice conditions can partially be explained by a younger ice pack in the Southern Beaufort that is more susceptible to summer melt than older ice prevalent in the region twenty years ago. Hence the variability in ice drift patterns might explain some of the variability in summer time minimum ice extent in the Beaufort. We are also interested in how the changes in storm patterns of the Beaufort affect the ice mass balance. Our buoys provide information about localized divergence of the ice pack, which results in ice growth, and convergence, resulting in ridging. With several years of data we hope to determine what the interannual variability of this phenomena is and whether it has a significant impact on the sea ice mass balance. In summary, we are investigating how changes in weather and storminess of the Beaufort are impacting the sea ice cover.