Thứ Bảy, 31 tháng 12, 2011

Ice Island Infrastructure

[Image: "From Seismic Arrays on Drifting Ice Floes: Experiences From Four Deployments in the Arctic Ocean" by C. Läderach and V. Schlindwein, from Seismological Research Letters].

In a paper published back in the July/August 2011 issue of Seismological Research Letters, authors C. Läderach and V. Schlindwein from the Alfred Wegener Institute for Polar and Marine Research discuss the benefits of tracking deepsea earthquakes using "seismic stations mounted on drifting ice floes." Indeed, they write, because of the lack of fixed ground points, "mounting conventional land seismometers on drifting sea ice is the only way to acquire seismic data in the Arctic Ocean."

In other words, they want to turn drifting fragments of Arctic sea ice into floating research stations, mapping earthquakes at sea.

[Images: "From Seismic Arrays on Drifting Ice Floes: Experiences From Four Deployments in the Arctic Ocean" by C. Läderach and V. Schlindwein, from Seismological Research Letters].

The authors have already seen considerable success with this method. In a short passage detailing how these systems are physically installed, we read that the seismic arrays "are deployed and recovered by helicopters operating from icebreaking vessels." However, "the time for station installation is very limited," due to weather and rough seas.
Station installation requires two people and a helping hand from the helicopter pilot, and takes about 30 minutes with the data loggers being programmed before the deployment flight. The limited time does not allow waiting for the sensor to equalize. Therefore, we only check the sensor response and locking of the GPS position before leaving the station.
While the authors compare this, briefly, to using buoys—indicating that their method is not all that different from other free-floating oceanographic instrumentation systems—the transformation of icebergs into scientifically useful platforms is a compelling example of how a natural phenomenon can become infrastructure with even the smallest addition of equipment. The iceberg has literally been instrumentalized: a temporary archipelago, too short-lived to appear on maps, turned into a scientific instrument.

In this context, it's worth revisiting the story of Drift Station Bravo, one of many inhabited icebergs in the Cold War era that had its own postal system, complete with historically unique stamp cancellations. [Image: Drift Station Bravo postage cancellation mark, via Polar Philately].

As explained on the website Polar Philately, Colonel Joseph O. Fletcher, commander of an Air Force weather squadron stationed in the Arctic, discovered "a large tabular iceberg... that had broken off the Arctic ice shelf... [and] gone adrift." This ice island was soon "codenamed T-1, taken from its original radar designation as a target." Future "ice islands" were codenamed T-2 and T-3.
On March 19, 1952, the U.S. Air Force led by Colonel Fletcher and some scientists landed on this ice island [T-3] in a C-47 aircraft, setting up a weather observation station. Fletcher established a research station that was manned at this big ice sheet for roughly the next 25 years, despite a grim quote given by the head of the Alaska Air Command at the time, a General Old, who was quoted in a Life magazine article of the time as saying "I don't see how any man can live on this thing."
It's worth repeating that Fletcher's team operated this weather station on a repurposed ice floe for 25 years.
Fletcher's Ice Island, and the research station that was located on it, rotated in circles in the Arctic Ocean, floating aimlessly along in the Arctic currents in a clockwise direction. The station was inhabited mainly by scientists along with a few military crewmen and was resupplied during its existence primarily by military planes operating from Barrow, Alaska.
The island—later renamed "Drift Station Bravo"—was inhabited long enough that it actually got its own postal network.

[Image: Letters postmarked from Drift Station Bravo, via Polar Philately].

From Polar Philately:
During the period of active habitation, T-3 covers [postage stamps] were serviced, each stamped with a variety of hand-stamped cachets and markings, dated, and often marked with a manuscript notation of the geographic position of the drifting station on that particular day of ops. The T-3/Bravo covers were often cancelled at Barrow or at a USAF base in Alaska, and then placed in the mailstream.
In other words, envelopes would be stamped with the latitude and longitude of the iceberg at the moment of a letter's departure.

[Images: Postal marking and a letter from Drift Station Bravo, via Polar Philately].

The story takes on clear geopolitical dimensions when we remember that Drift Station Bravo and its ilk—such as Drift Station Alpha, about which you can watch an entire documentary film—were created in direct response to the Soviet Union's own ice island program. The Soviets "already operated six drifting ice camps of this kind," we read in the documentary transcript, downloadable as a 27kb PDF, but, "owing to the particular strategic importance and sensitivity of the Arctic Basin, little information from these early Soviet stations had reached the West."

The transcript goes on to explain how the U.S managed to architecturally colonize these mobile platforms. Military civilization on the ice established itself as follows:
...a ski-equipped C-47 landed on the ice and deployed the first team of workers. It included an Air Force Major as camp commander and several soldiers with technical skills who had volunteered for 6 months duty on the ice, plus four of the typical tough and versatile Alaskan construction workers.

Modular buildings, called Jamesway huts, camp supplies, fuels, two small World War II Studebaker tractors, called Weasel, and a small bulldozer, were dropped by parachutes.
The story expands rapidly from here. In an article originally published in the September-October 1966 issue of Air University Review, we read that competitive Soviet drift stations apparently discovered a "second magnetic north pole... located near 80° N and 178° W, with magnetic medians extending across the Arctic Ocean," and that sulfuric gas fumes from a badly timed undersea volcanic eruption killed at least one unlucky crew member. A particularly eye-popping detail comes when we read that these researchers deliberately generated earthquakes in the iceberg they lived on: "we generated tiny earthquakes in the ice. The propagation of the compressional waves generated in this way are used to study the elastic properties of the ice."

This brings us back to C. Läderach and V. Schlindwein, whose paper in Seismological Research Letters examines the problem of "icequakes," or seismic activity internal to the ice floe on which their equipment rests, thus interfering with accurate measurements. They even mention at least one occurrence of a so-called "bearquake," when a curious polar bear came by to nudge the seismometer and see what was really going on. The authors refer to these events as "special signals."

In any case, will this floating seismic network adrift in the waters of the Arctic also receive its own stamps and postal cancellations? Presumably not, but it would nonetheless be interesting to examine the becoming-infrastructure of these ice floes in a larger geographic context.

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