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Notes from the Field

East and West: The Geography of Antarctica

November 19th, 2014 by George Hale

At first, the geography of Antarctica might seem a little confusing. From space, much of Antarctica looks featureless and white, meaning there are few features to guide you. It’s one thing to know that Pine Island Glacier is in West Antarctica, but for some it might be unclear which part of the frozen continent is which.

In the most general terms, Antarctica can be divided into three major areas: West Antarctica, East Antarctica, and the Antarctic Peninsula.

LIMA_overview_map

An overview map of Antarctica produced by the British Antarctic Survey to accompany the Landsat Image Mosaic of Antarctica, or LIMA.

The Antarctic Peninsula is probably Antarctica’s most prominent geographical feature and home to scientific stations operated by the United States, the United Kingdom, France, Australia, and other nations. This curved extension of the continent extends nearly 250 miles north of the Antarctic Circle and points toward the southern tip of South America. The Antarctic Peninsula has a number of glaciers and floating ice shelves that are changing rapidly because this region is warming faster than the rest of the continent.

Running along the length of the peninsula, and extending across the continent is a mountain chain known as the Transantarctic Mountains. In addition to supplying spectacular views, the Transantarctics serve as a sort of dividing line separating East and West Antarctica.

A view of the Transantarctic Mountains during IceBridge's 2013 Antarctic campaign.

A view of the Transantarctic Mountains during IceBridge’s 2013 Antarctic campaign.

Although the Antarctic Ice Sheet is a continuous mass of ice, it is sometimes helpful to think of it as two separate masses. The West Antarctic and East Antarctic ice sheets are separated by the Transantarctics, with ice on the west side generally flowing toward the Western Hemisphere and ice on the east side flowing toward the eastern hemisphere. (In both cases, this is actually flowing north…away from the South Pole.)

East Antarctica is considerably larger than West Antarctica, and its ice sheet is thick – nearly three miles (five kilometers) in some regions . The ice surface of East Antarctica is high and home to some of the coldest and driest condition on Earth.

The East Antarctic Ice Sheet is considered to be more stable than the West Antarctic. One reason is the shape and elevation of bedrock beneath the ice. Heavy masses of ice push down on bedrock, depressing some areas below mean sea level. If those low-lying areas happen to be near the edge of the ice sheet — which is the case in much of West Antarctica — then ocean water can make its way under the ice, speeding up glacier flow.

This is one of the reasons that, while both portions of the ice sheet are losing mass, West Antarctica is moving much faster. Recent studies of West Antarctica found that many of its fast-moving glaciers are in an irreversible decline.

sea ice shadow

Shadow of the NASA DC-8 on sea ice in the Weddell Sea. Credit: NASA / Jim Yungel

Antarctica is surrounded on all sides by the Southern Ocean. During the winter, ocean water freezes, forming a layer of sea ice of roughly the same area as the Antarctic continent. In recent years, sea ice around the continent has been increasing.

The ocean around Antarctica is divided into several seas. Starting to the right of the Antarctic Peninsula on the map is the Weddell Sea, which extends to Cape Norvegia, a small point of land jutting off of East Antarctica. Moving clockwise we go around the East Antarctic coast all the way to the Ross Sea, south of New Zealand. Next comes the Amundsen Sea, where large West Antarctic glaciers like Pine Island and Thwaites drain. We complete our trip around Antarctica by coming to the Bellingshausen Sea, to the left of the Antarctic Peninsula.

For maps of Antarctica, including some that use imagery from the Landsat satellite, visit:
http://lima.usgs.gov/download.php

To use an interactive Antarctic atlas, visit:
http://lima.usgs.gov/antarctic_research_atlas

Shackleton Range

Mountains of Antarctica’s Shackleton Range. Credit: NASA

Antarctica is one of the most inaccessible places on Earth. Yet in spite of this, it is highly vulnerable to human impacts. This vulnerability along with the pristine nature of much of Antarctica is what has motivated a number of protective regulations, many of which IceBridge personnel have to keep in mind every day.

The use of Antarctica is governed by an international agreement known as the Antarctic Treaty, which was signed by 13 nations in 1961. The Antarctic Treaty sets the continent and surrounding ocean aside for peaceful purposes like scientific research. Over the years more nations signed the treaty and more protocols regarding things like environmental protection were added to it.

NSF Chalet at McMurdo

The National Science Foundation Chalet, an administrative building at McMurdo Station in Antarctica. To the right of the building are flags representing the 13 nations that originally signed the Antarctic Treaty. Credit: NASA / Jefferson Beck

All over the continent are regions known as Antarctic Protected Areas. These fall into three categories, Antarctic Specially Protected Areas (ASPA), Antarctic Specially Managed Areas (ASMA), and Historic Sites or Monuments (HSM). When IceBridge plans its Antarctic flights these environmental protections and restrictions around known wildlife habitats come into play. The areas surrounding McMurdo Station, where IceBridge was based last year, are full of protected areas and wildlife sites. On some occasions as soon as the NASA P-3 took off the team had to maneuver their way around restricted areas.

Clearing the Air

On the DC-8 the time between takeoff and encountering a protected area is longer simply because of the distance between Punta Arenas and Antarctica. But there were two flights that took the DC-8 over a large managed area at the South Pole.

south pole station from above

An overhead view of Amundsen-Scott Station at the South Pole captured by the Digital Mapping System cameras aboard the NASA DC-8. Credit: NASA / DMS Team

South Pole Station is the site of a large ASMA that covers just over 26,000 square kilometers and places limits on ground and air travel and the use of certain electronics. One particular portion is known as the Clean Air Sector, a wedge-shaped region that extends 150 kilometers out and 2000 meters above the surface. To comply with the ASMA rules at the South Pole, the DC-8 had to pass over at high altitude and had to shut down laser and radar instruments to avoid causing interference with scientific gear on the ground.

Wildlife Protection

While large ASMAs like that at the South Pole are a factor on a few flights, IceBridge has to keep a watchful eye out for wildlife locations on each flight in Antarctica. Penguins, seals and other animals in Antarctica could be disturbed by overflying aircraft, therefore planes have to stay a minimum distance away and above known wildlife locations, though IceBridge keeps an extra margin of safety by staying farther away.

After a campaign is complete, officials with the National Science Foundation go over each survey’s flight path, checking the mission’s flight plans to make sure no wildlife protection rules were violated.

Flight path and penguins

Map showing the NASA DC-8 flight path and wildlife locations on part of the Antarctic Peninsula. Credit: NASA

To ensure that the plane keeps a safe distance, IceBridge uses its sophisticated navigation equipment and a detailed map of places where animals live in and around Antarctica. Prior to each flight, mission planners discuss wildlife locations with pilots and navigators and remain in continual contact with the plane’s flight station about these sites.

Studying Antarctica whether on the surface or in the air means that you’re going to have some sort of impact. The data gathered by researchers in Antarctica is valuable to improving our understanding of the world, so the best option we have is to minimize that impact. And with proper training and a good dose of care from teams working in Antarctica, scientists can learn about it while still preserving it.

For more about Antarctic Protected Areas, visit: http://www.ats.aq/e/ep_protected.htm

For more about the South Pole Station ASMA, visit: http://www.southpole.aq/management/zones.html

By Air and Sea: An Antarctic Transportation Hub

November 2nd, 2014 by George Hale

At the southern tip of Chile, the city of Punta Arenas is in a prime location for accessing Antarctica. This is one of the reasons IceBridge calls Punta Arenas home for several weeks during Antarctic field campaigns. But IceBridge isn’t the only scientific game in town. The U.S. Antarctic Program (USAP), British Antarctic Survey (BAS) and number of other organizations also rely on the Punta Arenas airport and the town’s ocean access.

DC-8 and Twin Otter

The NASA DC-8 taking off from the Punta Arenas airport. To the right is a Twin Otter aircraft used by the U.S. Antarctic Program. Credit: NASA / Kyle Krabill

The USAP brings two of its ice-capable research vessels, the Palmer and the Gould, to Punta Arenas. From there they carry out research cruises and transport people and cargo to and from Palmer Station, the National Science Foundation’s research base on the Antarctic Peninsula. In addition, USAP will sometimes base aircraft at the Punta Arenas airport on their way to and from Antarctica.

rv palmer

The R/V Nathaniel B. Palmer in the Straits of Magellan just off the coast in Punta Arenas, Chile. Credit: NASA / Michael Studinger

The United States isn’t the only nation with a strong presence in Patagonia. BAS research teams use Punta Arenas as a jumping off point for their research bases such as Rothera Station on the Antarctic Peninsula. In the photo below we can see a BAS Dash-7 and Twin Otter aircraft on the ramp at the Punta Arenas airport.

Dash 7 and Twin Otter

Twin Otter and Dash 7 aircraft operated by the British Antarctic Survey sit at the Punta Arenas airport. Credit: NASA / George Hale

In addition to the various Antarctic research programs working here, a number of companies that transport people, equipment and supplies to Antarctica fly in and out of Punta Arenas during the research season. Below are an IL-76 cargo jet operated by Almaty Air and a ski-equipped DC-3T aircraft flown by Antarctic Logistics Centre International.

dc8-and-il76

An Almaty Air IL-76 cargo jet at the Punta Arenas airport. To the right is one of the NASA DC-8’s engines. Credit: NASA / Jim Yungel

alci-dc-3-

An Antarctic Logistics Centre International (ALCI) DC-3T aircraft taxiing on the ramp on a snowy day at the Punta Arenas airport. Credit: NASA / George Hale