Saturday, September 18, 2010

I have not figured out how an entire week goes by without finding time to write a blog entry... So, here it is Sunday in McMurdo again. And it is really windy again, so probably no hiking today, on our one day off.

There has been both good news and bad this week regarding the long-duration balloons. There have been four launches, which is all of the payloads intended for studying the "ozone hole". Unfortunately, though, the balloon control center lost contact with the first balloon payload early this week. The balloon itself and the control systems were working fine, but they could not talk to the scientific payload at all. They tried for three days to regain communication, but were unsuccessful.  In some ironic stroke of fortune, though, the balloon was heading back toward the McMurdo area, which allowed for the possibility of destroying the balloon and retrieving the payload. This procedure was done early in the morning one day this week and the payload landed about 60 mi from McMurdo. The hope is to retrieve the payload as soon as the helicopters start flying (around the 28th of Sept).

Meanwhile, three payloads are floating above the Antarctic continent and seem to be returning excellent data about ozone and nacreous cloud particles. Through the miracles of modern technology, we receive our data via the internet every hour! The control center in Toulouse sends a query to the payload via Iridium satellite and the payload management software responds by sending down packets of data, also via Iridium. So, within about an hour of a measurement being taken, we know what the ozone amount is! Below is a  Google Earth map of where the 3 balloons are as of this morning. We hope they will all stay afloat for several weeks, if not months, providing us with lots of data about the formation of the "ozone hole".

Trajectories of the 3 long-duration balloons from launch to current position.

It is finally getting to the time of year when the sun is up for a normal day's length; soon it will be up 24 hours a day! McMurdo and the surrouding areas look quite different when the sun is really out than in many of the pictures I've posted before. So, I thought I would share some of these, just for fun.

Little chunks of clear ice glowing in the sun.

Balloon launch on a sunny, clear day!

Even though the sun is up, it is still low on the horizon - look at that long shadow!

Finally, I wanted to share another fun thing we get to see here fairly often. It is a mirage called "Fata Morgana", which is named after a character in the legend of King Arthur (Morgan Le Fay). She is generally regarded as a sorceress or magician and the application of her name to this mirage seems appropriate. It is also fairly common at sea, I understand. The mirage occurs when there is a layer of very cold air near the surface and a layer of much warmer air above it. You can imagine that, with all the ice and glaciers around here, the surface air is often quite cold. The difference in temperature bends the light, making distant objects look much bigger than they are.  See for yourself below - this is the largest Fata Morgana that any of us can recall having seen here.

Fata Morgana at the base of Mt. Discovery. In truth there is no cliff there at all!

1 comment:

  1. Linnea,

    What did you use to destroy the balloon to retrieve the payload?