Journal

Cruise Day 57

Speed 0 knots (kts) (on station)

Course n/a

Location Chukchi Slope, ~108 nm north of Barrow, Alaska

Depth 1625 m

GO DEEPER DISCUSSION: (see previous journal for the questions.)

Aurora occur in the thermosphere, the upper layer of the Earth’s atmosphere. There are some amazing photos and videos taken of aurora from space looking down at the Earth’s atmosphere, demonstrating that this phenomenon isn’t happening in space.

TODAY’S JOURNAL:

We’re making steady progress southwest back towards the Chukchi Sea, with a few short stops for repeat hydrography along the way to our next station. The depth is rapidly shallowing as we leave the abyssal plain of the Canada Basin behind to climb the Chukchi Slope. The breeze is sneaking back up some, but has brought blue skies and a sparkling blue seascape with it. The weather is forecasted to get windy again tomorrow and into Tuesday, so there’s a little bit of extra urgency in the sampling operations coming up in case we lose more time later due to high winds and seas.

For the last few days the ocean was calm enough for new ice to form on the surface. In contrast to the older thick ice we spent a lot of time in farther north the different forms of growing ice are more dynamic, moving with the swell and changing quickly in response to winds or overnight temperature drops. Here are some shots I hope you’ll enjoy showing examples of new ice:

Frazil Ice Swirls
Frazil ice is made of ice crystals floating at the surface of the ocean. Here we see bands of frazil ice that have been swirled by light winds.

Grease Ice and Open Water
This photo shows the contrast between open water (on the left) and grease ice (on the right.) The grease ice is thin, watery, and very flexible, moving with the swell but suppressing the little surface ripples seen in the open water.

Pancake Ice
Given enough time, ice crystals begin to coagulate into thicker plates that often get rounded, raised edges due to bumping into each other. This is called pancake ice. (There’s a chunk of leftover old ice in the shot, too.)

New Ice on Arctic Ocean
Looking out over the new ice is pretty cool- there’s still the up and down of a swell but the surface lacks any ripples and has a totally different luster than open water shows.

Pancake Ice and Sampling Rosette
Lowering the GEOTRACES sampling rosette next to pancake ice.

Small Boat Deployment in Pancake Ice
The Coast Guard’s smallest icebreaker returns to its largest! This shows the still-soft nature of new ice, with even a small boat able to gently nudge its way through the pancakes.

Sunset & New Ice
Last night’s sunset reflected over the oily-looking surface of new ice surrounding the USCGC Healy. By this morning the ice was gone, re-melted into the surface as it was agitated by rising winds.

GO DEEPER!

Here’s another Sunday riddle:

Voiceless it cries, Wingless flutters, Toothless bites, Mouthless mutters.

Aloft Con web cam updated every hour
Healy Track

That's all for now. Best- Bill

Details
Author
Bill Schmoker
Date
Location
Chukchi Slope, ~108 nm north of Barrow, Alaska
Expedition
US Arctic GEOTRACES
Weather Summary
Clear and Sunny, Moderate Breeze.
Temperature
28° F
Wind Speed
13 MPH
Wind Chill
18°F

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