March 21, 2003, Washington D.C.-- The National Ice Center (NIC) confirms Iceberg C-21 has calved from the Shackleton Ice Shelf. Confirmation of the calving was delayed until cloud free imagery was obtained. The Shackleton Ice Shelf is a large sheet of glacial ice and snow extending from the Antarctic mainland into the western Wilkesland Sea. Iceberg C-21 is currently located near 65.0S 95.7E and measures 24 nautical miles long by 12 nautical miles wide. A NIC Physical Scientist and Ice Analyst/Forecaster confirmed the calving of C-21 using the satellite image from the National Oceanographic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) Infrared sensor (Figure 1).

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 an iceberg is first sighted, NIC documents its point of origin. The letter of the quadrant, along with a sequential number is assigned to the iceberg. For example, C-21 is sequentially the 21st iceberg tracked by the NIC in Antarctica between 180-90E (Quadrant C).

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 Transportation). The National Ice Center mission is to provide worldwide operational ice analyses for the armed forces of the United States and allied nations, U.S. government agencies, and the private sector.

For more information, please contact:
National Ice Center
Naval Ice Center
Liaison
voice: 301-394-3026
e-mail: liaison@natice.noaa.gov