650 



To date, the predictioti of significant changes in the ice cover 

 has not been borne out by measurements. However, tliis 

 conclusion is primarily based on the analysis of passive 

 microwave data collected by satellite sensor systems, which are 

 limited in both spatial resoluuon and temporal extent. Clearly 

 the Navy's historical ice morphology data, which are both 

 detailed and predate satellite data b\- a decade, have much to 

 offer here This information is also of considerable use to 

 climatologists; to scientists studying the near-shore transfer of 

 pollutants; to individuals studying near-coastal sea ice dynamics, 

 as well as polynya (open water "leads" in the ice) and bottom 

 water formation. These data could also be important to modelers 

 carrying out studies of processes occurring over continental 

 shelves. 



It should also be noted that the historical ice morphology charts 

 are also of considerable importance both to groups interested in 

 developing coastal sea routes across the Arctic region between 

 the Atlantic and Pacific oceans, and to companies assessing the 

 operational difficulties of extracting the assumed large 

 petroleum reserves from the Arctic Shelves, hi both cases the 

 Navy data would allow an improved assessment of hazards and 

 trends. 



accumulated historical database be continued through the 

 National Snow and Ice Data Center (NSIDC). 



d. Findings 



The findings relative to historical ice moiphology are: 



• The reanalysis of the Ice Morphology data set, currently 

 underway at the NIC, should be completed wi th considetation 

 given to releasing a sanitized form of the final product as an 

 unclassified data set. 



• Classified holdings of accumulated historical sea ice inform- 

 ation in the Arctic region, if released, would contribute 

 significandy to the inventory of available data and facilitate 

 climate and ocean thermal studies in a significant way. 



• This information would be of considerable use because it is 

 an "undiscovered" historical record that will fill gaps in 

 studies of ice/water thermodynamic and hydrodynamic 

 processes and transport. 



• The pre-LANDSAT data should be digitized and a means 

 sought for its release in an unclassified derived product 



Finally, the Navy data should prove invaluable to individuals 

 investigating primary prodiiLtion m the food chain over the 

 .Arctic Shelves. Although the Arctic region has for many 

 years been assumed to be biologically barren, recent evidence 

 suggests that this is particularly not true over the continental 

 shelves. Indeed the ice edges in the Bering and Chuckchi seas 

 are proving to be areas of intense biological activity including 

 imponant fisheries. The improved data on the variability of 

 shelf ice conditions should definitely contnbuie to the analysis 

 of observed variations in biological stocks over the Arctic 

 Shelves. For instance, in the Bering Sea research suggests that 

 there are direct relations between ice conditions and 

 oceanographic factors that favor the survival of juvenile stocks 

 of important varieties of fish. 



With respect to these scientific questions, it is not the current 

 realtime products of the National Ice Center that are of prime 

 importance. Instead it is the accumulated historical database of 

 global sea icc information. It ib important that the release of this 



• A separate, classified ice morphology archive at 

 NAVMETOCCOM should be retained. This archive would 

 contain additional high- resolution analyses obtained &om 

 classified sources. 



:. ICE KEEL DEPTH ACOUSTIC DATA 



a. Data Description 



The only reliable methods of obtaining extended profiles of ice 

 kee! drafts (depths), and by implication, ice thickness, are 

 upward-looking, narrow-beam sonars (ULS) mounted on 

 submarines (Lagrangian data], or mounted at the top of subsur- 

 face floats moored to the seafloor (Eulerian data). Methods to 

 deduce ice thicbiess froni par.-uneters observable by satellite 

 are in an experimental stage and will, in any case, yield regional 

 or average thicknesses and "ice type" rather than data with the 

 high spatial resolution of the sonar method. 



Submarines have been acquiring scnar ice draft data since the 

 first Arctic crossing by Nautilus in 1957. In assessing the 



