Center Tracks Icebergs to Ensure Safety at Sea

By John Ohab
Special to American Forces Press Service

Feb. 13, 2009 - A multiagency center operated by the Navy, the National Oceanic and Atmospheric Administration and the Coast Guard provides continuous tracking and monitoring of ice movements to support national interests throughout the world. Navy Petty Officer 1st Class Gary Premo, a senior ice analyst at the National Ice Center, was interviewed on "Armed with Science: Research and Applications for the Modern Military" on BlogTalkRadio.com on Feb. 11 about the NIC's role in analyzing ice movements for safety of navigation and operations and in monitoring the changing Arctic climate.

"We record the ice change on a global scale. We also provide tactical support to the Navy and government agencies," Premo said.

Premo is an aerographer's mate, jokingly known as "weather guessers" in the Navy. They draw on extensive training in meteorology and oceanography to assess weather situations and provide commanders with tactical support. They can specialize in a variety of fields, including ice monitoring, aviation weather, hydrography, and anti-submarine and mine warfare.

Premo explained the breadth of factors that must be considered when monitoring ice, including variation in climate, currents and topography.

"To know a certain area, you have to know its climatological features dealing with weather, its wind regimes, and you have to know how to read the weather charts," Premo said.

Ice analysts rely on a wide array of satellite imaging and geospatial information technologies housed at the NOAA's Satellite Operations Facility. These tools include high-resolution synthetic aperture radar, infrared imagery, and passive microwave sensors for positional analysis of ice structures.

NIC also developed and maintains a system for naming Antarctic ice structures that have broken free from land. Icebergs that are at least 10 nautical miles at their longest axis are named and tracked through the open water until they melt below this threshold.

"We're actually the agency that does it globalwide. If you see a named iceberg in the news, that's actually us doing it," Premo said.

In addition to tracking ice movements, NIC provides tactical analyses and daily forecasts of ice conditions in the Arctic, Antarctica and the Great Lakes. The Fractures/Leads and Polynyas product is used by the U.S. Navy to identify ice fractures and aid in submarine surfacing. NIC makes daily sea ice edge measurements and ice consolidation data available to the public.

"The edge line is probably one of our most used products downloaded off our Web [site] and used by our customers," Premo said.

Premo described some of the climate changes observed in the Arctic over the past decade, including a decrease in "multiyear ice", the ice that historically survives the yearly summer melt.

"More and more of that multiyear ice has been diminishing," Premo said. "When you actually go into a melt season, that multiyear [ice] becomes smaller and smaller, which is making the Arctic more open water -- "sea ice free" as we call it -- and that's been happening over the last decade."

(John Ohab holds a doctorate in neuroscience and works for the New Media directorate of the Defense Media Activity.)