Experiences from two-years' through-ice AUV deployments in the high Arctic

We present operational experiences from two deployments of a small Gavia AUV in the high Arctic. Deployments took place from the U.S.-led APLIS camp, in the Beaufort Sea during May 2007 and from a small independent ice camp, on the fast ice just north of Canada's Ellesmere Island, in May 2008. Both deployments took place through a 3 times 1 m access hole in first-year (FY) sea ice made with hot water drilling equipment. A heated tent was placed over the hole and repeated runs made to characterise the sea ice in the area. The second deployment demonstrated the minimum logistics required to run a small AUV in this manner, only requiring a working tent, one sleeping tent and two or three people. It was staged from shore using skidoos. Study areas included all typical types and ages of ice - level and ridged FY ice, rubble fields (FY and multi-year (MY)), and MY floes and ridges. Both deployments were coordinated with simultaneous overflights by aircraft- and helicopter-borne instruments, allowing co-registration of snow+ice freeboard (from a scanning laser profilometer) and ice+snow thickness, from an electromagnetic induction device (HEM), operated by the University of Alberta. In situ measurements of ice thickness (grids and transects of drilled holes) validated results from all instruments.