From: Seelye Martin, Chief Scientist, Operation Ice Bridge
The issue of forecasting weather conditions over Antarctica presents a serious challenge to the Operation Ice Bridge DC-8 flights that get underway in just two weeks.
In the Southern Hemisphere, the Antarctic Ocean is unique in that the Antarctic Peninsula (the focus of many of our flights) is the only north-south oriented land barrier. Within this region, five or six weather systems accompanied by clouds and strong winds, rotate rapidly around the continent from west to east. The clouds from these systems extend from the ocean to the ice sheet, and are associated with strong winds. These systems are partially blocked by the mountains on the Peninsula that rise to approximately 10,000 feet (3,000 meters). Between these weather systems, periods of clear sky occur.
(See for yourself. Here is a link to one Antarctic forecast tool I’ve been using: http://www.mmm.ucar.edu/rt/wrf/amps. After opening the first page, click on “animations” at the top left; in the next frame select “cloud base” under the first pull-down menu on the left. The image above is a sample of what you’ll see.)
The challenge in planning the flights is that we require clear weather over the target area to operate the lasers. For aircraft safety, we also need to avoid severe storms.
We will obtain our forecasts by working with the Chilean weather service, with polar scientists from the Centro de Estudios Cientificos (Center for Scientific Studies), by examination of satellite imagery downloaded at the airfield, and by use of web-based forecasts.
Another mission challenge is that as it proceeds, our ability to obtain a cloud-free flight decreases. This occurs because at the beginning of the flight series, we have a variety of geographically dispersed targets, such as the sea ice in the Weddell and Amundsen seas, the Peninsula glaciers, and the ice sheet in the vicinity of Pine Island and Thwaites glaciers. This gives us geographic flexibility and the ability to choose a cloud-free region from many different sites. As the flights proceed, the number of our target sites decrease, and finding cloud-free conditions over the target will become more difficult.