Wind, Snow and Ice: Summer in Antarctica
By Julian Spergel
The theme of the past week has been the weather. Weather is of course always happening, but in the lingo of McMurdo Station, ‘weather’ means ‘bad weather.’ Over the past week, I’ve seen the accumulation of around six inches of very fluffy snow.
In the center of McMurdo Station, visibility has not yet decreased too much, but on Williams Field there were several days of Condition 1, the most extreme, with visibility of less than one hundred feet. In terms of temperature, it has not gotten too cold, with the thermometer hovering between the mid-teens and low twenties Fahrenheit. Nevertheless, all flights have been grounded for nearly a week.
Windy and snow blowing! Conditions on Willy Field, Antarctica during the recent spat of bad weather. (J. Spergel)
When weather permits, the Rosetta team has been checking in on the instruments in our Williams Field tent and on the airplane, digging out the entrances to the tent, and remaining in a state of preparedness for our next flight opportunity. In between our check-ins the cargo staff went out to investigate and found the back doors of the tent blown open, letting in snow and cold. They relayed to us that the instruments are looking ok, and this was later confirmed by two of the members of the Rosetta team when they were able to make it down to the field.
It isn’t all bad news. The flights that were going to the South Pole were grounded as well, and the fresh fruits and vegetables that would have gone to them were served to McMurdo Station instead. We enjoyed fresh avocados at every meal for several days as snow blew outside! Their loss was our gain!
This austral summer seems to be unusual, with unseasonably active weather. People who have been here in recent years note that the weather during November is normally clear. According to NOAA’s weather statistics for the period 1961-1990, McMurdo Station receives on average a little less than half an inch of snow water equivalent in November. This year, the McMurdo weather office measured nine inches of snow in the 24 hours between 1 A.M. November 16th and 1 A.M. November 17th. This would equal approximately a full inch of snow/water equivalent in just 24 hours! It has been a snowy month.
Antarctica is a polar desert, but as mentioned before in this blog, it also experiences extreme weather. The weather patterns of the Ross Ice Shelf in particular have been a topic of research. The triangular Ross Ice Shelf is bordered by the Trans-Antarctic Mountains on one side, the high glaciers of Marie Byrd Land on the second and the Southern Ocean on the third. As a result, the ice shelf experiences a confluence of air masses. From the mountains and glaciers, cold, dense air sinks downslope and flows across the ice shelf in the form of katabatic wind. These winds join the clockwise-spinning air mass system coming from the Ross Sea. The high elevation of the mountains acts as a wind barrier and creates barrier winds parallel to the mountain ranges, which also add to the force of the wind vortex. As a result, the cyclonic Ross Ice Shelf Airstream is a permanent, year-round part of the climate. Ross Island, where McMurdo Station is located, sits in the path of this wind and, like a rock in a stream, creates eddies on its leeward, i.e northward, side. Precipitation events occur when relatively warm, moist air is brought to Ross Island, and that moisture is released as snow.
In other news, I was startled by this skua sitting in front of the dorm building, and now the rest of the Rosetta team has nicknamed me “Skua.”
For more information about Rosetta-Ice, check out our website and the archive of this blog. Have questions about Rosetta-Ice or about living and working in Antarctica? Feel free to email your question to firstname.lastname@example.org, and I will try to answer it in the next blog entry!
Julian Spergel is a graduate student at the Department of Earth and Environmental Science at Lamont-Doherty Earth Observatory and is blogging from Antarctica. He works with Professor Jonathan Kingslake on analyzing spatial and temporal trends of supraglacial lakes on the Antarctic Ice Sheet using satellite imagery.