The Sunday Science Lecture

16 Oct

Every Sunday night in the dining room there is a science lecture put on by the scientists or their support staff.  Feeling adventurous as I sometimes do, I decided to attend the first one of the Winfly season.  The topic was the Ozone Hole and if it was getting better or not.

The lecture didn’t begin until 8pm and having worked my first brunch (starting at 6am-and feeling REALLY tired), I was a bit leary about how I would stay awake for an ENTIRE hour.  Around 8pm is when my body has gotten in the habit of telling me I am tired (in a number of ways!).  I poured myself a cup of tea and sat up front.

Dr. Jennifer Mercer, a research scientist from the University of Wyoming, is here ‘three months each year to measure the ozone layer by launching balloons 100,000 feet into the stratosphere.’   She first began the lecture with discussing the different layers in the atmosphere.  Some I had heard of, most of which I had not.  She then moved onto talking about the ozone hole and the ozone layer.  I couldn’t follow all the details (I was REALLY tired and having a difficult time staying awake.  Not because it wasn’t interesting, but because I was SO tired!), but the details that I found most interesting are:

1.  The Ozone Hole is only over the Antarctic from August through September.  The depletion of it is caused by a chemical reaction with chlorine and bromine. 

2.  The LIDAR (Light Detection and Ranging) is a big laser that is sent straight up into the sky to help measure moisture and cloud content in the atmosphere.    This instrument is used in determing information regarding the ozone hole.

The LIDAR being used here.

The LIDAR being used here. It's the green laser in the center of the photo.

3.  Nacreous clouds can be seen extremely well in Antarctica.  Here are a few examples of the nacreous clouds seen here at the end of August.

A real photo (taken by F. Sheil, a coworker that was here during the Antarctic winter) of some nacreous clouds.  The photo looks fake, but it's not.

A real photo (taken by F. Sheil, a coworker that was here during the Antarctic winter) of some nacreous clouds. The photo looks fake, but it's real.

Here is more information about nacreous clouds:

The nacreous color of the cloud is a result of diffraction of light through ice crystals in the clouds. In themselves, nacreous clouds are not too uncommon, and can be seen in mid-high latitudes when the atmosphere is cold enough to freeze the droplets of water in the clouds. The nacreous clouds that we see at this time of year in Antarctica though, are a special variety of nacreous cloud – a type 2 polar stratospheric cloud (PSC).

PSCs are unique to the polar regions. As their name implies, they form in the stratosphere, between 10 and 25 km  (6.2 – 15.5 miles). They also only form when stratospheric temperatures get below about -110F. There are several types of PSCs, containing some combination of nitric acid, sulfuric acid and water. The clouds we observed on Monday were type 2 PSCs, which are pure ice – these form in the coldest conditions (-120 F), and are thus the most uncommon. Because they are so high up (Mondays were approximately 20-22 km (13 miles), as determined by the Crary LIDAR), the sunlight is able to hit them before it hits us here on the ground, giving us spectacular light shows. The wavy look of them is due to wave action in the stratosphere, which is often associated with type 2 PSC formation.

Another amazing shot (also by F. Sheil) of the nacreous clouds at McMurdo.

Another amazing shot (also by F. Sheil) of the nacreous clouds at McMurdo.

 

 

 

 

 

 

 

 It was all pretty cool stuff and even though I fell asleep for a short part of it, I found it interesting. 

For more information about this subject, check out http://antarcticsun.usap.gov/science/contenthandler.cfm?id=1530

or http://ozonewatch.gsfc.nasa.gov/.

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