17 September, 2003

Katabatic Winds

Well, our launch was scrubbed. We were all set, we went to the galley for dinner thinking everything was perfect for another launch...and then the winds picked up, tremendously! From almost nothing but a few gusts, to winds approaching 50 knots, these strong and sudden winds are known as Katabatic winds. They are common in Antarctica because they form from the heavy cold air that is high on the Antarctic plateau. Often conditions are right for this dense air to fall through the mountain passes and down toward the coast where we are. It is quite spectacular to see this happen. I attach some weather graphs showing the sudden increase in the winds along with the cold temperatures. The wind chill at 50 knots was close to -55C. But really it was ok to walk about, and I enjoyed getting blown about and feeling the cold on my face. When you are out there you can think about anything, like why is it that no ice cream flavor is named after Antarctica? I mean after all, the Arctic has Eskimo Pies...

Our launch is not possible in high winds for two reasons. The first is the balloon may tear. But the second is physics. We can't run fast enough to keep the payload directly under the moving balloon as it is rising. You would have to be able to run 100 meters in 10 seconds. Only a few people in the world can do that.

In the distance you can see the snow whipping up on the ice shelf.

The red arrow shows when the winds started to pick up. Right when we were supposed to launch!

The cold air flows off the high interior to the coast.

The temperature drops when the winds come in. This is the outside temperature, not the wind chill.