Iceberg A-68 Calves off Larsen-C Ice Shelf on the Antarctic Peninsula

By Evelyn V. Bowens
U.S. National Ice Center
July 13, 2017

Suitland, MD — The U.S. National Ice Center (USNIC) discovered a new iceberg has calved from the Larsen-C ice shelf on the east side of the Antarctic Peninsula. This iceberg, name A-68, is located at 67°55’ South, 60°35’ West, in the Weddell Sea. The iceberg measures 84 nautical miles on its longest axis and 25 nautical miles on its widest axis, and is slightly smaller than the state of Delaware.

A-68 was confirmed by USNIC Ice Analysts using the Sentinel-1 image (shown below) and longwave infrared imagery from the Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the NOAA/NASA Suomi National Polar-orbiting Partnership (NPP) satellite.

A-68 is expected to drift east-northeast along the Antarctic Peninsula in the Weddell Gyre over the next several months. It will likely fracture into smaller bergs before drifting far enough north to enter the Antarctic Circumpolar Current.

Iceberg names are derived from the Antarctic quadrant in which they were originally sighted. The quadrants are divided counter-clockwise in the following manner:

A = 0-90W (Bellingshausen/Weddell Sea)
B = 90W-180 (Amundsen/Eastern Ross Sea)
C = 180-90E (Western Ross Sea/Wilkesland)
D = 90E-0 (Amery/Eastern Weddell Sea)

When first sighted, an iceberg’s point of origin is documented by the USNIC. The letter of the quadrant, along with a sequential number, is assigned to the iceberg. For example, C-19 is sequentially the 19th iceberg tracked by the USNIC in Antarctica between 180-90E (Quadrant C). Icebergs with letter suffixes have calved from already named icebergs, where the letters are added in sequential order. For example, C-19D, is the 4th iceberg to calve off the original C-19 iceberg.

The National Ice Center is a tri-agency operational center represented by the United States Navy (Department of Defense), the National Oceanic and Atmospheric Administration (Department of Commerce), and the United States Coast Guard (Department of Homeland Security). The National Ice Center mission is to provide the highest quality strategic and tactical ice services tailored to meet the operational requirements of U.S. national interests and to provide specialized meteorological and oceanographic services to United States government agencies.

Satellite image of Iceberg A-68
Figure 1: Sentinel-1 image of A-68 dated July 12th, 2017

For more information, please contact:
National Ice Center
Command Duty Officer
Voice: (301) 943-6977
Twitter: @usnatice
Facebook: @usnatice

The U.S. National Ice Center is a tri-agency center operated by the Navy, NOAA, and Coast Guard and provides global to tactical scale ice and snow products, ice forecasting, and related environmental intelligence services for the United States government.

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