*Tap *tap *tap .... Is this thing on?

It has been a while since I have posted here, but I am happy to report I am once again preparing for another trip to Antarctica! In fact, I'm tentatively scheduled to depart three weeks from today. It seems so far away, yet so close! Much has happened since my last post, some of which I will cover in this post and some in later posts. I have (again) gone through the PQ (Physical Qualification) process and am just awaiting my travel documents. We tentatively expect to be on the ice for about five weeks  but the scope of the work this time will be primarily to do maintenance on each site and prepare them for another winter season. As with last year, I'll be updating my blog again with updates on each site as we progress during our time on the ice.

With regards to the sites themselves, all four sites that we installed last year appear to have survived the winter and are still transmitting data back to us here in Boulder. As part of the installations, we had installed webcams that were rated for the cold temperatures and also could see in the dark (or more appropriately, in the infrared spectrum). We haven't been able to grab all of the videos because of bandwidth restrictions, but we have grabbed a few from the Willie and Phoenix sites. Willie appears to have survived without any issues. Phoenix, though, sustained some damage to the gauge shielding (likely due to some screws loosening in the wind). Hopefully things will hold together until we can get down there in a month and commence repairs.

Snapshot of Phoenix site with some minor wind shield damage.

We also began some data analysis from the sites over the summer and are already seeing some exciting results. The figure below shows a snapshot of some of the preliminary data from the Tall Tower site. The labels are hard to read because the figure covers six months of data but the light blue line is the wind speed, the orange line is the temperature (notice the drops to -50 in the latter part of the plot .... brrrrrrrr) and the dark blue line is the measured accumulation. The interesting aspect of this data is we can see there were periods of snowfall in the early parts of the plot (the left half) but the accumulation values always gradually drop back to zero. This is because the precipitation is sublimating (changing directly from a solid to a gas) out of the gauge during these times. Near the beginning of March though, the sublimation mostly stops and the precipitation remains in the gauge for the rest of the plot. This is significant because March is when the sun set for the winter. This analysis implies that there is significant sublimation of precipitation during the summer months and relatively little sublimation in the winter months. We are continuing our analysis of this but if this is true, it means the actual amount of precipitation that is being added to the Antarctic Ice Sheets may be less than expected and may only occur during the winter months.

Data from the Tall Tower site, approximately 100 miles away from McMurdo on the Ross Ice Sheet.

That's all I have time to update for now. As we continue to get closer to our deployment date, I'll likely post one more update before heading down to the ice. I also wanted to post a quick thank you to all my blog subscribers and for all of the positive feedback I have received from all of you. I will continue to strive to keep this blog informative and hope you'll enjoy Chapter 2 as I return to the ice for another field season. As a thanks, I have posted a few more photos below from last season that I haven't posted before.

That one day when a 757 landed while we were installing the Willie Field Site.

A rupture in the pressure ridges on the ice sheet thrust this ice over 10 feet into the air. Mount Erebus can be seen in the background with a small puff of steam emitting from the top of the volcano.

A Weddell seal snoozes in the sun showing off the snow and ice frozen to its underside. Pressure ridges can be seen rising in the background.

I managed to snap this shot of one of the LC-130 aircraft flying overhead. Notice the landing gear are skids and not wheels!