After a week of orientations, trainings, and adapting to life on station we finally made it out on to the sea ice yesterday. Our goal was both to get some practical experience and to scout out the potential locations for our field camp that will be put in come summer in October. We headed out in one of our PistenBullys and a truck fitted with tracks (Mattracks) to go look at cracks in the ice and learn how to profile them. This is critical process in order to avoid float testing any of our vehicles, which is generally frowned upon. It is however, a good way to get one of the annually recurring cracks named after your (now submersed) vehicle- Big John Crack, Backhoe Crack… etc.
Alasdair Turner, a mountaineer and sea ice guide here on station showed us how to profile a crack and determine if it is safe to cross. The various vehicles we employ have different requirements based on the track length and weight so it is important to know exactly what you are driving over and drilling to measure thickness is crucial.
There are three main types of ice in McMurdo Sound-
- Annual Sea Ice
- Salt water ice that forms and breaks up each year
- Multi Year Sea Ice
- Salt water ice that does not completely break out each summer and is generally thicker and stronger than annual ice
- Continental Ice Shelf
- This is essentially a massive glacier, hundreds of meters thick that floats over the sound. It formed from snow fall over the continent that compact and flow north over the ocean.
Our goal was to find a stable bit of multi year ice within a few hundred meters of the ice shelf, allowing us to drill through the relatively thin sea ice (~2-4 m thick) and deploy Artemis. We think we found a good spot, and hopefully it will allow us to have a good long season extending at least into December and give Artemis access to the nearby ice shelf to explore. A post about Sunfish is coming soon, we’re about to begin checking out her systems in the tank over the coming days.