NOAA 98-69

                                        
CONTACT:  Patricia Viets, NOAA               FOR IMMEDIATE RELEASE
                                             10/15/98

NEW ICEBERG BREAKS OFF RONNE ICE SHELF IN ANTARCTICA

An iceberg larger than the state of Delaware has broken off the Ronne Ice Shelf in Antarctica, the National Ice Center reported today.

The iceberg, named A-38, is 92 x 29.9 miles and covers an area roughly 2750.8 square miles. It broke off the second largest ice shelf in Antarctica, located in the southern Weddell Sea.

Mary Keller, a scientist at the National Ice Center in Suitland, Md., sighted the iceberg using satellite data. The data are from an instrument on a satellite in the Defense Meteorological Satellite Program -- the Operational Linescan System, which has a spatial resolution of .55 km (.34 miles). These satellites are operated by the Commerce Department's National Oceanic and Atmospheric Administration.

The National Ice Center is a tri-agency operational center represented by the U.S. Navy (Department of Defense); the National Oceanic and Atmospheric Administration (Department of Commerce); and the U.S. Coast Guard (Department of Transportation). The National Ice Center's mission is to provide world-wide operational ice analyses for the armed forces of the United States and allied nations, U.S. government agencies, and the private sector.

Ice shelves are massive, floating sheets of snow and frozen water that encircle the Antarctic mainland. Scientists at University College London believe that the breaking off, or calving, of icebergs is an important mechanism in the disintegration of ice shelves, and a possible indicator of global warming. Scientists there report that the mechanics of ice shelf fracturing remain poorly understood. A research group at the college is planning to study ice core samples from the Ronne Ice Shelf to learn more about fracture and deformation properties.

The last known iceberg of this magnitude to calve off a Southern Hemisphere Ice Shelf was B-9 in the Ross Sea in October 1987.

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 to 90 degrees West longitude (Bellinghausen/Weddell Sea)
                    B = 90 West to 180  (Amundsen/Eastern Ross Sea)
                    C = 180 to 90 East (Western Ross Sea/Wildesland)
                    D = 90 East to 0 (Amery/Eastern Weddell Sea)
When an iceberg is first sighted, the National Ice Center documents its point of origin. The letter of the quadrant, along with a sequential number, is assigned to the iceberg. For example, A-38 is the 38th iceberg the ice center has found in the Antarctica in Quadrant A.

###

Note to Editors: An image of A-38 is on the World Wide Web at: http://www.natice.noaa.gov Click on Icebergs; then click onto Southern Hemisphere Icebergs The GIF image of A-38 is located above the weekly iceberg update table.