Modelling: Sea Ice Sensitivity

Modelling is an equally critical component of Sea Ice Camp and needs to be documented as well!

While the afternoons have been dedicated to on-ice activities, in the mornings we have sat in on short lectures and exercises on modelling in the classroom.

Two days ago, Cecilia Bitz gave a short lecture on sea ice sensitivity in climate models. Here we are discussing the worksheet that she distributed to all the groups. We tested the sensitivity of sea ice by varying the initial ice thickness, snowfall rate, downward longwave radiative flux, snow and ice albedo.

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Modelling in the Yellow Group

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Modelling in the Blue Group

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Day 2: Ice Morphology

On-ice fieldwork today was on ice morphology with Andy Mahoney and Chris Polashenski. The goal of the session was to see some of the different ice types off the shore of Barrow. For Camp participants, this station also known as “snowmachining.” After a brief orientation (e.g., where to find the throttle and brakes), we set off.

We travelled north towards Hajo’s ice mass balance station, which was set up in flat, shore-fast, first-year ice. The station tracks thermodynamic changes in ice mass balance.

To get an idea of the ice thickness, we drilled a few holes away from the station. The first hole we drilled yielded a depth of 85 cm. Only a few feet away, however, the ice was 57 cm. The enormous variability within such a short distance was surprising.

Heading north, we happened across a lone instrument standing sentinel on the ice surface. Upon closer inspection, we realized it was one of Ignatius’ buoys! The discovery warranted a short photo op. Jinlun left the instrument intact.

We continued to follow the whaling trail that the locals would take to the ice edge earlier in the whaling season. A few seals could be spotted in the distance, basking in the diffuse sunlight. We were on the lookout for multi-year ice. For those of us who hadn’t yet seen multi-year ice, we weren’t sure what to look for. After some time, Andy halted when we arrived at some brilliant blue melt ponds. We had arrived! At least, this is what we were told. We learned that the colour of the ponds and their positioning next to some egg carton-like hummocks were signs of a multi-year ice floe.

We pressed onwards along the old whaling trail until we came to a steep-ish ridge of broken ice. We parked the snow machines so that we could climb up on top we caught views of jumbled sea ice and, far off, the ice edge. The darkened cloud edge indicated open water. A few polar bear footprints halted us in our tracks.

Standing there, we admired the views and contemplated the ice rubble. Stretching out to the ice edge and running alongside the ridge, we saw broken ice, patches of blue, white, and gritty gray. How could this be studied? How could it be represented in sea ice models?

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Orientation

Day 1: Orientation

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Why a picture of Winston Churchill, you might ask? Or more specifically, why Churchill smoking a victory cigar?

You’ll have you ask Don for the full details about ‘victory cigars,’ but he informed us that while on SHEBA, it became one of his customs to enjoy a Tootsie roll (instead of a cigar) after getting a job well done. With this in mind, we each received a special fieldwork package, which consisted of a Tootsie roll lollipop and “Rite in the Rain” notebook. Last but not least, Don and Marika announced which teams we would be in for the afternoon fieldwork. In total there were 4 teams with 5 members. I was assigned to the Yellow Group and given a fancy yellow-ish camo neck warmer/bandana/hair thing that could be worn several different ways, according to the package.

Rules of Arctic Fieldwork:

  1. “Eat as much as you can, whenever you can.”
  2. Remember to keep records of your data
  3. Make a plan (but also don’t get too attached to it)

Day 1: Physical Properties Station

Day 1: 

After a morning spent at BARC listening to the safety orientation and brief overviews on modelling, remote sensing, and in situ observations, we headed outside for our first session of on-ice activities.

Today’s session was with Hajo Eicken on the physical properties of sea ice. In other words, core-drilling time!

The weather was fine and I wondered if I had overdressed with my parka and snow pants. I even took off my hat and gloves. It was a short walk off shore to the site where we set up to drill ice cores–far enough to get a good measurement but not so far that it was difficult to walk to. Walking along the ice, Hajo and Bonnie consulted about whether the surface layer was deteriorating ice or re-textured snow. Carefully, we treaded through the partially melted ice, probing to find the bottom of the (shallow) ponds.

After a quick survey of the area, we set up to drill a few cores to get the temperature and salinity profiles of the sea ice. We even tried to make an ice slab but unfortunately, due to difficulties cutting it out, we left it for another group to attempt tomorrow.

Congratulations, JZ!

Jinlun has crossed the Arctic Circle!

Upon arriving in Barrow, Melinda presented Jinlun with a Blue Nose medal. These are given out by the US Navy to individuals as they cross the Arctic Circle to commemorate the occasion.

It was a delight to be here for this moment 🙂