Ice and Medicine at the end of the earth

Posts tagged “Climate Science

Hercules Dome, Antarctica

I am off to Antarctica again shortly to a site called Hercules Dome. Is it called Hercules Dome because of the effort to get there? Maybe. To get there from Seattle, I will fly to Christchurch New Zealand, before going to McMurdo Station and then South Pole. And then one last flight back north to Hercules Dome.

Hercules Dome is about 250 miles north of South Pole. It’s in the direction of the Antarctic Peninsula and South America and labeled HD in the map below (with a bunch of other ice core sites which might get mentioned over the course of these blog posts).

Is Hercules Dome named after airplanes used to move people and stuff all over the continent? The Air National Guards flies LC-130s, which specialized versions of the C-130 Hercules aircraft for polar field work. The Hercs can be fitted with skis and able to land both on groomed runways and on smooth portions of the open ice sheet. So maybe Hercules Dome is named because it’s a nice place for Hercs to land. To my knowledge, no Hercs have landed there, but it is flat and minimally affected by wind, so early pilots may have recognized it as a potential emergency landing strip.  

We are headed to Hercules Dome to determine where best to drill an ice core. In future posts, I’ll explain how we look through the ice to the rock underneath; how we look at the ice itself; how we will model how the ice flow; and lots about what goes into doing Antarctic field work.


The South Pole Ice Core

I’ve posted plenty about life at the South Pole, but what about the science? We recently completed our first drilling season, reaching a depth of 736 m.

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We are drilling an ice core at South Pole because of the unique climate here. South Pole is cold, even by Antarctic standards. It is the coldest spot for a deep drilling project by the USA. Other cores have been drilled at colder sites, but what makes the South Pole unique is that has received much more snow than those other sites.

More snow means higher resolution. Basically, if it snows twice as much, we collect twice as much ice for a given time period allowing us to make more detailed measurements. We also benefit from the atmosphere being trapped in the bubbles in the ice faster.

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The cold temperatures are necessary to preserve trace gases. When I say trace gases, I don’t mean carbon dioxide (CO2), which is measured in parts per million, or methane (CH4) which is measured in parts per billion. I mean gases like carbonyl sulfide (COS – that’s CO2 with an S instead of the second O) which is measured in parts per trillion. COS gets lost in warm ice, so the cold is needed to preserve it.

At 736 m, the ice is about 10,000 years old. After drilling to 1500 m next season, we will be at about 40,000 years. Each layer of ice gets thinned by ice flow which is why more time is packed into each meter of the deeper ice.

Once we have gotten the ice back to the US, we will begin the scientific analysis