In 1993 scientists from academic institutions were invited to participate in a U.S. Navy submarine cruise under the arctic sea ice aboard the USS Pargo to explore using a submarine as a platform for scientific observations. This mission was so successful that it was expanded into a five-year program called SCICEX, Scientific Ice Expeditions. As a part of this program, six arctic cruises have been completed.
Each cruise had several civilian scientists on board. Investigators for the science program were selected from proposals submitted to the Office of Naval Research and the National Science Foundation. The scientific objectives for each mission were developed by the selected investigators. The staff of the U.S. Navy's Arctic Submarine Laboratory was responsible for planning the mission and providing support to the scientific investigators.
The SCICEX cruises across the Arctic Ocean have provided valuable insights into the circulation of the Arctic basin, the recent state and dynamics of the sea ice cover, the movement of carbon within the ocean system, and the structure and origin of the Arctic bathymetric features. A complete list of the SCICEX projects, project summaries, the tracks of each submarine cruise, etc. can be found at the SCICEX home page maintained at the Lamont-Doherty Earth Observatory of Columbia University.
In 1993, The USS Pargo made the first civilian oceanographic submarine cruise in the Arctic Ocean. Polar Science Center scientists James Morison and Roger Colony (now with the International Arctic Research Center, University of Alaska) participated in the research cruises.
Other Related Links
The Arctic Submarine Laboratory's web site contains many news articles that highlight SCICEX cruises.The U.S. Navy Commander Submarine Force offers photographs from the SCICEX '99 cruise.
Ice Thickness Distribution Test
The "SCICEX Ice Thickness Distribution Test" project uses submarine observations to study the spatial and temporal variations of sea ice thicknesses in the Arctic, and to improve the numerical simulation of ice thicknesses distribution. The project is led by Drs. Drew Rothrock of the Polar Science Center, Applied Physics Laboratory, Gary Maykut of the Department of Atmospheric Sciences, University of Washington, and Alan Thorndike, University of Puget Sound.
The arctic ice pack is composed of many different thickness of ice, each having different physical properties and each interacting differently with the atmosphere and ocean. The way in which these thickness are distributed in time and space determines the overall characteristics and behavior of the ice pack. Information on the ice thickness distribution is critical for calculating ice properties such as surface temperature, albedo, strength and deformation, as well as for estimating regional fluxes of mass, heat and salt. These fluxes directly affect mixed layer structure and water mass formation in the Arctic Ocean.
A theory was formulated to predict changes in the ice thickness distribution (Thorndike, A.S., D.A. Rothrock, G.A. Maykut, and R. Colony, 1975, The thickness distribution of sea ice, J. Geophys. Res., 80, 4501-4513). This theory has become an integral part of many sea ice models, yet it involves assumptions about such physical processes as the formation of leads and ridges that are little more than guesses, and it ignores other important processes such as the effects of variable snow thickness, melting at floe edges and melt ponds. Since its initial development twenty years ago, the theory has not been directly tested, primarily because of the lack of suitable data. The convergence of SCICEX cruises with the Surface Heat Balance of the Arctic Ocean(SHEBA) field experiment in the Beaufort Sea offered a unique opportunity to obtain the needed data.
Support for this project is from the National Science Foundation through Grant No. OPP-9617343 and from a joint ONR-NASA grant NAGW-5177.
Ice Thickness Distribution Test Publications and News Articles
The initial results of the Ice Thickness Distribution Test project have been published inRothrock, D.A., Y. Yu, G.A. Maykut, 1999. Thinning of the arctic sea-ice cover, Geophys. Res. Lett., 26(23), 3469-72. Download a PDF version of the paper. Click here to see summary information and news articles about this research.
Babko, O, D. A. Rothrock, G.A. Maykut, 1999, The role of rafting in the mechanical redistribution of sea-ice thickness, submitted to J. Geophys. Res.
Ice Thickness Distribution Test Data
An ice thickness distribution (ITD) has been derived from the SCICEX '97 submarine survey of the initial SHEBA site at 75.17oN and 142.23oW in the Beaufort Sea on 2 October 1997. The entire survey, centered at about 75.7oN and 145.2 oW, consisted of 7 sample tracks and covered an area approximately 200 km in diameter. These observations were made during the period 28 September to 1 October 1997. To calculate the ice thickness distribution, the observed ice drafts were multiplied by a constant 1.12.
This ice thickness distribution (ITD) is derived from the submarine '97 SHEBA survey. The first column of the data file is the thickness at the lower boundary of a bin (in centimeter), and the second is the fraction. The time of observation is from 28 September to 1 October 1997. For complete ice draft profiles, their statistics, and the data document, please contact the National Snow and Ice Data Center.
Click here to download the data (Version 2 data set with ambiguous zeroes being eliminated from draft profiles) and please send an email to Yanling Yu to let her know. This data can be acknowledged as the following: "This data set was provided by the project 'SCICEX Ice Thickness Distribution Test', under Grant No. OPP-9617343 from the National Science Foundation." Any comments or questions regarding this ITD can be directed to Yanling Yu.
Creating a 47-Year Public Record of Sea-Ice Draft in the Arctic Ocean
In collaboration with W.B. Tucker at the Cold Regions Research and Engineering Laboratory, Drew Rothrock is leading a new project on Creating a 47-Year Public Record of Sea-Ice Draft in the Arctic Ocean. The objectives of the Sea-Ice Draft in the Arctic Ocean project are to: (1) process critical historical ice draft data acquired by U.S. Navy submarines in the Arctic Ocean from 1958 to the present; (2) place ice draft profiles and their statistical summaries in a public archive, the National Snow and Ice Data Center (NSIDC); (3) process and place in the same archive ice draft data from future U.S. Navy submarine missions; (4) collaborate with others holding ice draft data from British submarines and from moored upward-looking sonars to broaden the public database to include continental shelves, Fram Strait and the Greenland Sea.
In the SCICEX Ice Thickness Distribution Test project, it has been found that the ice cover in the 1990s is over a meter thinner than it was during the period 1958-1976. This result is based on a small portion of the data record and needs to be examined with a fuller data set. At present, the available temporal record of ice draft over the Arctic Ocean is spotty with only half of the submarine cruises from 1986 to the present being processed and placed at NSIDC. The potential for expanding the Arctic ice thickness database is thus enormous. The Sea-Ice Draft in the Arctic Ocean project will extend back to 1958, the beginning of the historical record of submarine-observed ice draft. By doing so, both data coverage and volume will be more than tripled and will allow exploration into climate variability as evidenced by the Arctic Ocean ice cover over nearly five decades.
This project is funded by the National Science Foundation under Grant OPP-9910331.
The SCICEX 2000 Workshop was held in October 1998 to discuss science accomplished during the first five cruises under the Scientific Ice Expeditions program, and to consider what might supersede SCICEX. Participants were from the civilian scientific community, funding agencies, the U.S. Navy, and several international colleagues.
For information about the workshop, and to obtain a copy of the report from the SCICEX 2000 Workshop, Arctic Ocean Science from Submarines (published April 1999), please click here.
Rothrock, D.A., Y. Yu, G.A. Maykut, 1999. Thinning of the arctic sea-ice cover, Geophys. Res. Lett., 26(23), 3469-72. A PDF version of the paper, summary information, and news articles about our research are available here.
Babko, O, D. A. Rothrock, G.A. Maykut, 1999, The role of rafting in the mechanical redistribution of sea-ice thickness, submitted to J. Geophys. Res.
Langseth, M., T. Delaca, G. Newton, B. Coakley, R. Colony, J. Gossett, C. May, P. McRoy, J. Morison, W. Smethie, M. Steele, and W. Tucker, SCICEX-93: Arctic cruise of the U.S. Navy nuclear powered submarine USS Pargo, J. Mar. Technol. Soc., 27, 4.
Morison, J.H., M. Steele, R. Andersen, 1998, Hydrography of the upper Arctic Ocean measured from the nuclear submarine USS Pargo, Deep-Sea Res., I 45, 15-38.
Steele, M. and T. Boyd, 1998, Retreat of the cold halocline layer in the Arctic Ocean, J. Geophys. Res., 103 (C5), 10,419-10,435.
Last Updated: Wednesday December 18, 2002
