Working with Greg

Joined: 23 Mar 2004 Posts: 72

Today I spent some time with Greg Huey, who works with Georgia Tech.

His part of the project is a little less labor intensive than the rest, but just as complicated. This means that he is still taking detailed measurements within the ambient (air) and the firn (snow). The difference is that his system is automated so that he does not have to do the sampling or analyzing by hand. He does occasionally have to do troubleshooting or replace gas tanks, but mostly he is monitoring data and analyzing what that data means.

Greg is measuring several gases. One of those is ozone. He has a machine that air is pumped into and exposed to light through one of two chambers. One of those chambers has a scrubber on it that removes the ozone. Each chamber has a detector on the end that measures the amount of light visible through the air. The chamber with air and ozone will give off less light. By comparing the two detectors, the machine can determine the amount of ozone present in that air sample.

He also measures nitric oxide (NO) by reacting it with ozone (O3). This reaction gives off light that can be measured. By looking at how much light is given off, he can determine how much nitric oxide (NO) is present. Remember, nitric oxide is formed by hydroxyls (OH) in the snow. You can see by looking at the chart, the more light (which means the more hydroxyls present), the more nitric oxide that is formed!!

The other thing that Greg looks at is how much sulfuric acid (H2SO4) is present in the snow. Sulfuric acid is formed from the combination of sulfur dioxide (SO2) and hydroxyls (OH). Sulfur dioxide is put in the air by burning fossil fuels. He uses a machine called a mass spectrometer to measure the sulfuric acid. He can identify how much sulfuric acid is present, because the machine knows how much mass an ion of sulfuric acid has, and shows how many ions of that particular mass are present.

While we were at lunch, Barry called up to the big house that there was a possible problem with the nitric oxide detector. As Greg and I were walking back to the sat camp, I noticed that I could smell a strong diesel fuel odor. It turns out that the NO detector was picking up NO being emitted from the generator building, because the winds were blowing in just the right direction. Just goes to show how pollution travels. The generator shop is only one small building- almost 1 mile away from the bonnet probe (where all the samples are taken from), and it’s pollution was picked up by the experiment! Imagine how far pollution from several million cars on the roads must put out!

I also spent part of the afternoon helping with the shading experiments. You’ll remember that this is the experiment where we block all light (visible and ultraviolet), then just ultraviolet light, and then leave it out unblocked, changing from one to the next each hour.

Things are starting to wind down here at Summit. Most of the researchers will be done collecting data on Sunday or Monday at the latest. They will need to spend several days packing up all of the equipment so that they are ready to move out on Thursday morning. Hard to believe that my adventure is coming so quickly to an end!!