And so continues the helo bonanza. On Thursday 16 January we were planning to helo out to Ferrell AWS to switch the data transmission from Argos to freewave. Of course, all of these flights depend on good weather, and Tuesday and Wednesday were beautiful days for flying. On Thursday, however, there were some low clouds apparent on the satellite imagery to the east of White Island, which is where Ferrell AWS is located. This didn’t bode well for a helo landing, as the surface becomes nearly impossible to define when there are low clouds over ice. Lee and I arrived at the helo pad, talked with the helo techs and decided that we would take the trip out there and determine whether it was safe to land upon arrival.
There were only high clouds in the McMurdo area, but a few minutes after we departed we started seeing the low clouds. They became thicker and more widespread as we approached Ferrell.
Low clouds, as seen from the helo. The surface became completely obstructed from view the closer we got to Ferrell. The clouds did have a cool, hill-like appearance though.
A few miles from Ferrell, we decided that it was unsafe to land so we turned around and headed for McMurdo. Over the intercom, Lee said to me that now we could go to Pegasus AWS and finish up work there, as we would have time to take a shuttle from McMurdo. The pilot and helo tech heard this and said, “Why don’t we just drop you off at Pegasus?” We said, “Why not!!”
Lee and I arrived to Pegasus in style. Most often, to get to Pegasus from McMurdo you would take a shuttle, and the drive can take an hour or more. It’s funny to think that Lee and I took a helo from McMurdo, to Ferrell, then to Pegasus in about the same amount of time as a shuttle ride to Pegasus.
It was very generous of the helo guys to drop us off. It saved us a lot of time and gave us a chance to eat our flight lunches in the Pegasus galley. Once well fed and rested, we headed out to our AWS to finalize the freewave transmissions there.
Pegasus AWS, with White Island (where we are directing our transmissions) in the background
As we were waiting to verify the transmissions were successful, I noticed a very cool cloud feature on the horizon near White Island. It’s called Kelvin-Helmholtz instability, and it occurs when there is a velocity and density difference across two layers. This can result in a wave-like cloud structure as it did for us that day.
Kelvin-Helmholtz wave clouds
Once we were done admiring that spectacle, we verified that the freewave transmissions worked at Pegasus. After several trips to the station, we finally diagnosed the problem and fixed it successfully. We then headed back to the airfield to catch a shuttle to McMurdo. On our short drive to the airfield, we were treated to the always-welcome sight of four penguins, seemingly on a journey somewhere.
Four Adelie penguins at the airfield
On Friday 17 January, we (continuing the helo bonanza) flew out to Ferrell AWS. This time, the weather cooperated. The skies were clear between McMurdo and Ferrell and beyond. The only very minor issue was the wind; it wasn’t too windy but it was constant as we worked. At Ferrell, we wanted to switch the data transmission to freewave. We also noticed that the lower temperature sensor was buried, so while Lee was fixing up the freewave antenna, I dug out the sensor to be raised.
Ferrell’s lower temperature sensor
Unfortunately, after trying to adjust the direction of the antenna and attempting to connect via the laptop, we could not establish a connection between Ferrell and White Island AWS. We will have to visit the station again; fortunately, the helo schedule is pretty open, so we are actually on the schedule to do this visit sometime next week. For now, Ferrell is still transmitting via Argos.
Ferrell AWS after we did our work
Today, Saturday 18 January, we were hoping to yet again continue the helo bonanza to Linda AWS, but we got canceled due to weather. It is far too windy (~60 mph winds at Black Island, which is on the way to Linda). Hopefully we can get there next week.
More updates as they come.
Cheers
Dave
