One of the great things about being here is the people you meet. Just about everyone who is down here really wants to be here and usually has a pretty interesting story. People froma huge variety of backgrounds come down to support the scientists. Of course, there are also scientists who come down each year. Every Wednesday and Sunday night there is a science lecture. We have gone to two of them and they were both excellent. The notes below are from the lecture this Sunday about icebergs...
I am going to give you a quick summary and it will probably sound choppy...so hang on. From an earlier conference I attended in July, the speaker told us that Arctic ice is shrinking about 3% each year. However, the Antarctic sea ice is growing. Some people use this stat from Antarctica as "proof" that global warming isn't really happening. The speaker explained that the reason the ice is growing in Antarctica is because giant icebergs are calving off the Ross Ice shelf and also the Larson Ice shelf...the presence of these icebergs blocks the oceans currents from moving in and out as much, this causes less temperature change...this causes less sea ice breaking up...this causes more ice...
See if you can find pictures of the Larson Ice shelf in 2003 and what happenend to it in a very short period of time. A before picture shows an iceshelf with some cracks and crevaces, a picture from a week later shows a big chunk of the shelf destroyed. It is an area that is about 100 miles long, 40 miles wide. It started to show signs of melting from sattelite photos. The melting ponds seeped into the ice shelf and a condition called "hydraulic jacking" occured. Basically, the melted water seeped in, froze, expanded, and caused a wedging motion to break the ice off the shelf. Within a few days...the entire shelf didn't just break off as one iceberg...it completely exploded into hundreds of icebergs. The satellite photos of this are amazing and scary. These icebergs migrate north and melt...potentially raising sea levels. This example is what they are afraid the entire Antarctic continent will start experiencing. It is theorized that if the entire Ross Ice shelf were to do this (not likely)...sea levels would rise 6 feet immediately. That is without the ice even melting yet! This is scary stuff!
So to hopefully tie this choppy summary together...even though the ice is growing, it is growing because ice bergs are breaking off the ice shelf...causing a back up of water not moving...this water stays frozen and even freezes more. However, with global warming occuring....the tops start to melt...wedging holes...and then blammo! It all shatters and will eventually migrate to the equator and melt.
For a close to home example...the station I am living at is called McMurdo station. There was a giant iceberg that broke off the Ross Ice Shelf five years ago and they called it B15. B15 is as large as the state of Connecticut. That is large enough to supply every human with 10 lbs of ice every day for the rest of their life. In other words, this iceberg contains enough water to equal the same amount of water used in the US for two years. This thing is big! The presence of B15 stopped the sea ice from melting and breaking up and leaving McMurdo sound the last 5 years. That has affected penguin rookeries and seals getting into our sound. The iceberg has finally left the sound and they think that this year the sea ice will melt and leave like usual and that the animals will be back. We shall see, eh?
It should be noted that the formation of icebergs is a normal process and that about every 50 years or so a huge iceberg forms from the iceshelves. What happens is that the iceshelf is essentially a glacier which moves away from the continent towards the ocean. At some point, part of the shelf breaks off into huge icebergs. These icebergs follow counterclockwise currents around Antarctica and then get stuck in fairly predictable places.
7 comments:
Ocean Currents and Climate
As global warming increases, there will definitely be effects on climate and ocean currents. I unfortunately don't really know what those effects will be. It is certain that currents moderate and control much of the global climate, as they change so will global weather patterns and climate. Global warming will impact those - there are models which predict what will happen. I just don't know what exactly they predict. In order to limit the amount of change, the basic requirement is to burn fewer fossil fuels and decrease the emmision of greenhouse gases.
Weather
The station that we are staying at is on the coast of Antarctica - we are actually on Ross Island. Antarctica is the driest and coldest continent on the planet. We may only get about a foot of snow on the coast in a year and at the south pole they may not even get a centimeter of new snow fall. Blowing snow is what we will see most often when the storms come.
Ross Ice Shelf
In order for the ice shelf to collapse, the temperature of the ocean underneath and the air above the shelf would have to rise pretty dramatically. The only reason that the ocean would rise by 6 feet if the shelf collapsed is that it is not already in the water, as most glaciers are. So the entire shelf would fall and displace a huge amount of the water.
Icebergs
Apparently about every 50 years a huge iceberg will break off of an ice shelf somewhere. Due to the currents around Antarctica, they travel in a counterclockwise path around the continent and eventually head north where they melt in warmer waters.
Dear Michael,
The coldest we have experienced is -44 F with the wind chill and the actual temp was -10 F. The warmest weather we've had so far was today at a whopping +12 F. This warm weather coincided with the worst storm conditions because of high winds and they shut the station down for many hours.
Dear Michael,
The coldest we have experienced is -44 F with the wind chill and the actual temp was -10 F. The warmest weather we've had so far was today at a whopping +12 F. This warm weather coincided with the worst storm conditions because of high winds and they shut the station down for many hours.
Dear Michael,
The coldest we have experienced is -44 F with the wind chill and the actual temp was -10 F. The warmest weather we've had so far was today at a whopping +12 F. This warm weather coincided with the worst storm conditions because of high winds and they shut the station down for many hours.
Shanna,
We have satellite capabilities here, but if differs at different locations. The South Pole only gets satellite connections a few hours a day and we get periods of interuption with no transmission. We use the satellite for internet and phone use.
As for fuel issues, I think the solar power would be useless here because over half the year is in darkness. Not for sure if they could use solar power during the 5 months of sun. We use diesel fuel here to power generators that run everything.
Fruit and vegetables are flown in from New Zealand. Some weeks you don't get much, but last week they flew in 5,000lbs of veggies and fruit. Here they call it "freshies". Some freshies are grown here in a hydroponic greenhouse that is about the size of two yellow buses fused together. I haven't visited it yet so I don't know much about it.
Shanna,
I saw the score online. Nice job. Good luck against Creek.
All the trash is boxed up and sent back to the States via ship. On the supply ship's return. About 60% of the stuff gets recycled - we sort our trash into different bins. Human waste is treated at a water treatment plant here at McMurdo. Field camps bring human waste back to the station and then they deal with it. I don't know what happens to the waste water once it is 'clenaed'.
Good luck with the design project it sounds like fun.
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