Don's Log

   9 August - 11 August: Across the Marginal Ice Zone

Tuesday 9 August
Aboard Healy Northbound in the Chukchi Sea
74 16.4541 N, 160 32.4003 W         
First ice at 0650! We’re at the edge of the ice pack and only a few miles away from the first coring station. The ride from Dutch Harbor to 73 N was very smooth even when the seas were rough. The Healy rides extremely well.

The 7 person ice observing team met on the bridge at 0800 to do our first ice watch. We are using Hajo’s web based system. It is pretty straight forward, you basically just fill in a form. Of course there is the usual confusion over “Percentage of what? Is it the ice area or the total area?” In this case it is always percentage of total area, which avoids a lot of confusion. Ice observations will be made every 2 hours. Two people only have to do one set a day, unfortunately they have the 2 AM and 4 AM readings. I have 6 and 8 PM. We will probably change as time goes on. After lunch I recalibrated the ASD and took a set of incident spectral irradiances.

All in all, not too much ice today, with concentrations between 20 to 30%. Spent the evening getting ready for my talk tomorrow – the kickoff of the weekly science presentations. The title is “The Arctic and Climate Change: One Sick Canary.” Weather permitting we may get an opportunity for a helo photography flight tomorrow.

First ice at 0650.

Wednesday 10 August
Aboard Healy Northbound in the Chukchi Sea
75 10.05 N, 158 49.47 W
Yesterday’s high cloud ceiling and partial sunshine are gone. It’s low clouds, scattered fog, and drizzle. The Healy reached site 2 early this morning and we were done shortly after breakfast. Unfortunately, the ice is so thin and the floes so small that getting out onto the ice is not an option. We are, however, scheduled for a helo photo flight at 1300, weather permitting. Bruce and I got the camera gear together so we will be ready for the flight. I also finished up my talk.          

Sandwiches for lunch – great. Fog after lunch – not great. Our photo flight is cancelled due to weather. I made a couple of incident spectral irradiance measurements this afternoon. Bruce dug out the web cam so we can make sure it is working properly.

I was the evening’s entertainment giving the weekly science lecture. There was a very good turnout, with a lot of interesting questions. Tomorrow we are hoping for better weather, with flight ops meetings at 0800 and 1300.

The Eppley radiometers. These instruments measure the amount of incoming shortwave and longwave radiation. The data are automatically recorded in a datalogger stored in the white box.

Thursday 11 August
Aboard Healy Northbound in the Chukchi Sea
76 32.172 N, 157 6.352 W         
Another gray, drizzly, foggy day. It’s unlikely that we will get to fly. Spent part of the morning watching the ice go by. It is still pretty sorry looking – primarily first year ice with substantial numbers of melt ponds, most of which have melted through to the ocean. However, its composition is different from yesterday. The floes are much bigger, some hundreds of meters in diameter. The floes are barely hanging together. The melt ponds form a network of flaws that riddle the floes.

It’s reminiscent of SHEBA conditions at the end of July, just before the breakup. One good windstorm would break the ice apart. Much of the first year ice is very gray looking and is probably thinner than 0.5 m. There are a few multiyear floes that are distinctive with their white surface and beautiful blue melt ponds.

After lunch, Bruce and I got out the web cams and installed them in the bow, one portside and the other starboard. We let them run from the ship until it’s time to install them on the ice. While the fog persisted the rain stopped so I was able to do an incident spectral irradiance measurement from the flying bridge.

We continue to make excellent progress through the relatively thin ice towards Site 3. Tomorrow we are again waitlisted for an afternoon photography flight; weather permitting. Also, we have an opportunity to take a small boat to the ice during the station 3 stop. It could be an exciting day.

Melt ponds come in different sizes, shapes and colors. Some are dark and some are beautiful shades of blue. Why are they different? Stayed tuned for the answer.

Figure 1. Dark melt pond.

Figure 2. Blue melt pond.

Back to Transit to the Ice Edge

To A westward excursion