The Impact of Submarine Depth, Speed Sonar Systems on Arctic Sea-ice Draft Measurements

Measurements of Arctic sea-ice thickness are critical to understanding the global climate system. One of the best sources of thickness data are upward looking sonar measurements of ice draft made by U.S. Navy submarines (draft is the submerged portion of floating sea ice, about 93% of the thickness). Currently, there is a public archive of 30 years of submarine draft data spanning from 1975 to 2005, with broad coverage of the central Arctic Ocean. The submarine data have proved instrumental in documenting regional and temporal variability, long term trends, testing and improving numerical climate models, validating satellite-based ice products, and fostering research and discussion on a wide range of academic and national policy issues.

The proposed work has two components. First, we will extend the record of ice thickness measurements back in time by another 15 years to 1960. Data from 7 cruises covering the span from 1960 to 1970 will be processed by the University of Washington and archived at the National Snow and Ice Data Center (NSIDC). Second, we will lay the groundwork for extending the record into the future as the submarine fleet transitions to new equipment and methods of data acquisition. This component will result in the development of techniques to ensure the consistency of future data with the existing archive, ensure that new data be of the highest possible quality, and provide an assessment of the quality of future data.