Thursday, December 20, 2007

Sea Ice

The sea ice in McMurdo Sound freezes each year. During the summer, it usually melts all the way up to base. McMurdo's site was originally chosen because it is the furthest point South that a ship can navigate when that sea ice melts. If the ice melted more they could go farther.

A Bassler plane on the sea ice runway.

We use the sea ice for roads and as a runway. Each year, those roads and runway are reestablished. We have another runway on the glacier for after the sea ice melts. We don't use it all the time because it is much farther away and therefore more costly to operate.

Mt. Erebus in the background. The sea ice runway road in the foreground.

Annual sea-ice thickness varies seasonally between 8 and 11 feet by the end of the growth period. Thinning by bottom melting starts about mid-December and continues until breakout in late January or early February. We usually move the sea ice runway out to Williams Field as soon as the melting starts.

A radar bubble on the sea ice runway.

While the sea ice is being used as a runway, the minimum thickness is 70 inches for a C-17 to land on it. The minimum length of the runway is 10,000 feet. There is a 69 page document that goes on and on about the smallest details of what needs to be done. It is more complicated than you'd ever guess. The maximum parking load is 600,000 lbs for 1 hour or 490,000 lbs for 3.2 hours. The most important thing we are monitoring is sea ice temperature because as the temperatures increase the weight of the aircraft is adjusted lower. They also have a surveyor measuring how much the sea ice bends every time a plane lands on it. If it bends too much, they'll decrease the weight on the next plane or close the entire runway.

More buildings that make up part of the sea ice runway facility

What other numbers do I have for you ... The average water temperature is -1.9 degrees Celsius or 28.58 degrees Fahrenheit.

The sea ice runway closed three weeks ago. However, until this week we were still using the sea ice as a road network out to field camps. This map shows our surrounding area and details about the sea ice thickness in early December when we were closing the runway.

Sea ice thickness map.

So I wanted to write about this to convey just how amazing and strong the sea ice is. I'm not sure if I did that, so just think about it again 600,000lbs of plane on eight feet of sea ice equates to 187.5 2008 Toyota Tacomas!!

Next blog should be about my trip out onto the closed sea ice!!

Monday, December 17, 2007

Under the sea

The seaweed is always greener
In somebody else's lake
You dream about going up there
But that is a big mistake
Just look at the world around you
Right here on the ocean floor
Such wonderful things surround you
What more is you lookin' for?
('Under the Sea' from the Little Mermaid)

First up, I want to thank Bruce Miller for posting all of his underwater photos. Every photo in today's blog is compliments of him. It's a treat to see photos of a place that so few of us ever get to go. I bet more people have been to the South Pole (about 7,000 I think) than have ever been diving under the sea ice in Antarctica. I tried to limit the number of photos, but there were so many great ones I kept more than I deleted.

These creatures live under the sea ice year round. They don't migrate for the winter. I have no idea how much light can penetrate eight feet of snow covered sea ice, but I can't imagine it is too much. Yet, so much still thrives. I've heard that once the ice starts to melt the plant life begins to bloom and visibility drops from 500 ft (?) down to 10 ft so winter is actually the best time to explore the sea floor.

I, unfortunately, don't know what most of these creatures are so I am mostly just posting pictures. Enjoy!!


Octopus. I'm not sure if the other two legs are underneath it or not.

Weddell seal coming down from a hole in the sea ice.

Lots of life here. There must be a source of nutrients under that pile.

Two starfish doing the Unstuck.

Underwater pill bug?

Big Brother seal is watching you.

Sea fairy?

The end of a riveting game of hide and go seek.

0xygen meter and underwater note taking

It was THIS big!

This is how you make fish lips.