model. This is only about half of the 7962 target 

 sightings during 1995. The 3902 targets entered 

 into HP's drift model do not represent all of the 

 targets reported to IIP. Sightings of targets out- 

 side HP's Area of Responsibility (AOR) were not 

 entered into the model. Most of these were far to 

 the north of HP's AOR, in areas not covered by 

 HP's model. Coastal iceberg sightings were also 

 screened, and only those with the potential to drift 

 into the trans-Atlantic shipping lanes were entered 

 into the IIP model. 



Table 3 includes icebergs detected south 

 of 48°N plus the number of icebergs which were 



Table 3 

 Number of Icebergs South of 48°N 



Number of Icebergs South of 

 48°N during 1996 



Month 



Number 



Total 



611 



\ 



predicted to drift across 48°N for each month of 

 1996. During the 1996 ice year, an estimated 

 611 icebergs drifted south of 48°N; whereas, dur- 

 ing 1995, 1432 icebergs had drifted south of 48°N. 



IIP classifies the severity of the ice sea- 

 sons based on the historic iceberg counts of its 

 entire 82 year history. Ice years with fewer than 

 300 icebergs crossing 48°N are defined as light 

 ice years; those with 300 to 600 crossing 48°N as 

 moderate; and those with more than 600 cross- 

 ing 48°N as extreme. 1 996 was at the lower end 

 of the "extreme" classification, and in reality was 

 a "moderate" year for iceberg conditions. 



The 1996 season was the fourth year that 

 IIP used its iceberg Data Management and Pre- 

 diction System (DMPS). This system, which is 

 nearly identical to the iceBerg Analysis and Pre- 

 diction System (BAPS) used at the Canadian Ice 

 Centre, Ottawa, combines an iceberg drift model 

 with a deterioration model. The model uses wind, 

 ocean current, and iceberg size data to predict 

 the movement and deterioration of all ice bergs 

 entered into DMPS. The drift prediction model 

 uses a new historical current data base (Murphy, 

 Viekman and Channel, 1996), which is modified 

 weekly using satellite-tracked ocean drifting buoy 

 data, thus taking into account local, short-term, 

 current fluctuations. Murphy andAnderson (1985) 

 described and evaluated the drift model. 

 The iceberg deterioration model uses daily sea 

 surface temperature and wave height information 

 from the U.S. Navy Fleet Numerical Meteorology 

 and Oceanography Center (FNMOC) to predict 

 the melt of icebergs. Anderson (1983) and 

 Hanson (1987) described the IIP deterioration 

 model in detail. 



Fourteen satellite-tracked ocean drifting 

 buoys were deployed to provide current data for 

 HP's iceberg drift model during the 1996 season. 

 The buoys are similar in design to the Worid 

 Ocean Circulation Experiment (WOCE) and were 

 equipped with surface temperature sensors and 

 a drogue centered at 50 meters. Drift data from 

 the buoys are discussed in the IIP 1996 Drifting 

 Buoy Atlas, which is available upon request. 



