Thursday, November 24, 2005

The Antarctic Climate and South Pole Weather

Antarctica is perhaps one of the harshest climates on all of Earth. There are a number of factors that influence its very extreme climate, but most important of all is its very unique location. As I mentioned in the previous post about time, the South Pole is a special place because it is one end of the Earth’s rotational axis; like the center of a merry-go-round. It’s also an important fact that the Earth’s axis is tilted in such a way that at different periods during the year, the poles (north or south) point towards or away from the sun. These two factors have a strong influence on the atmosphere, weather and temperature of the continent.

Before we get in any more detail, lets understand the difference between the north and south poles (besides that Santa lives on one not the other). The North Pole is located in the Arctic, in the middle of the Arctic Ocean and is surrounded by the continents of North America, Europe and Asia. Around the location of the North Pole, the Arctic Ocean remains frozen with about an average of 12-14 feet of ice. So, the North Pole is located on a floating patch of ice. There are a number of species of mammals that live in the Arctic climate, mammals like polar bears, foxes and deer (but no penguins).

The South Pole however is a completely different story. The South Pole is not located on water but instead on the continent of Antarctica and is surrounded by seas and oceans like the Pacific. That means below the ice at the South Pole is solid ground. The ground is quite a ways down though, instead of about 12 feet of ice, the South Pole sits on top of about 9000 feet of ice! That’s about 10 of the tallest skyscrapers stacked up on top of each other! The animals that can live on Antarctica have to be very well suited for the cold and able to travel large distances out into the ocean to find food; animals like penguins, seals and sea birds (no polar bears).

Now, the first thing you notice when you get to the South Pole is that it’s COLD! I mean, its really really cold. It’s so cold that my breath freezes to my eyelashes and clothes! It’s so cold that on a 20 minute walk to work the other day, my water bottle froze half way. During the last week or so I have been here, the temperature has been about -30 degrees Fahrenheit. Typically, it will start to snow back at home when the temperature reaches about +30 degrees. That’s 60 degrees more than the temperature here! That’s like the difference between a beach day and a snow day. Compared to the temperatures here, winter back home feels like summer! This isn’t even the coldest it can get though, in fact right now its pretty warm for the South Pole because it is summer in the Southern HEemisphere. In the winter, the average temperatures are about -60 degrees. The coldest temperature ever recorded at the South Pole was -117 degrees, and the coldest on Earth was at the Vostok Antarctic Station, -128 degrees!

So why is it so cold down here? Well the main reason both poles of the Earth are cold is because they get the least amount of sunlight of any place on Earth! First of all, both poles experience 6 months of the year with the sun completely below the horizon, in complete darkness for nearly 3 of those 6 months. For the other half of the year that the sun is above the horizon it never gets very high. You might know that at noontime, especially during the summer, the sun is almost directly over your head. This never happens at the poles, the highest the sun ever gets is about a quarter of the way up.

Why isn’t it so bad on the North Pole? The main reason the South Pole is so much more an extreme climate and is over so much more ice and snow has a lot to do with the fact that it is on an actual continent. The oceans are a really good distributor of temperature, so ocean currents can balance the cold temperatures of the North Pole. This keeps the ice from building up too thick. Aside from the coast, the Antarctic continent is isolated from ocean currents. Antarctica is about the size of the US and Mexico combined. The South Pole lies approximately the same distance from the coast as say Chicago.

Perhaps the most interesting thing about the weather in Antarctica and at the South Pole is the precipitation. You might think that since there is so much ice and snow at the South Pole, it must be snowing all the time. Absolutely … not! In fact, it snows very little at the South Pole, almost not at all! Most of the interior of Antarctica receives less than 2 inches of snow (water equivalent) per year. That’s less snow per year than a typical Chicago snowstorm. In fact, this is so little precipitation that it technically makes most of Antarctica a desert! The South Pole is one of the driest deserts in the world. Yet, being so cold and isolated, the snow never melts and after millions of years can accumulate.

Still, this doesn’t mean that snow won’t pile up at the South Pole during the course of just one year. There are strong winds that blow from the high altitude interior of the Antarctic continent outwards towards the coast. There winds have a special name; the Katabatic winds. Since most of the continent is a flat plateau, this wind blows snow right across. Wind blown snow slowly piles up and builds into thick glacial ice. At the South Pole, wind driven snow accumulates at a rate of about 12 inches per year. This has a very noticeable effect; the buildings here slowly disappear from year to year as the snowdrift buries them! One building housing a telescope project named ASTRO is being evacuated and demolished this year before it is completely buried. In fact, it is expected that the new South Pole Station will also be buried within 30 years.

These extreme climactic and weather features of the South Pole, and Antarctica as a whole, are major factors that make it such a unique, dangerous, and scientifically interesting place!


Blogger Wolfgang said...

This is the first time that I found a really interesting blog by clicking on the Next button.

Thu Nov 24, 01:37:00 PM CST  
Blogger plymouth rock said...

This is great stuff - and not so specialist that I can't understand it. Thank you!

Tue Mar 14, 03:59:00 PM CST  
Blogger Lazcantotegui said...

Very interesting! I found Antartic amazing and it is good to read from sciencinst like you about work and life in the pole!

Thu Aug 30, 06:05:00 AM CDT  
Blogger - viviihunn said...

This comment has been removed by the author.

Sun Oct 05, 07:06:00 PM CDT  
Blogger - viviihunn said...

great blog! i needed to do an assignment on antarctica =P and this really helped :) thanks

Sun Oct 05, 07:09:00 PM CDT  

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