Administration, and U. S. Coast Guard 

 facility located in Suitland, Maryland, 

 provided less than 1% of the targets and 

 approximately 1°o of the reports in 1999. 

 NIC is Ice Patrol's partner and provides ice 

 information it obtains from various sources. 



Regardless of the numbers and 

 percentages reported above, the continued 

 success and viability of the Ice Patrol 

 service in the North Atlantic depends 

 heavily on all the contributors of ice 

 reports. 



1999 Icebergs South of 48'N by Month 

 of 22 Total Icebergs 



12 



10 



8 



fc 



o^-i=I 



1^ 



MAR 



APR 



MAY 



JUN 



JUL 



Figure 5. Icebergs South of 48 N for 1999, 

 excluding growlers, bergy bits and radar 



To compare with previous year's ice 

 seasons, 1999 was negligible in terms of 

 season length and number of merged 

 targets (Figure 4). In previous years, IIP 

 has used the number of icebergs south of 

 48°N as a metric for ice season severity 

 (Figures 5 and 6). This metric includes 

 both icebergs detected south of 48°N and 

 those that are predicted to have drifted 

 south of 48^N. The icebergs south of 48'N 

 measurement is generally preferred by IIP 

 because it places the emphasis on 

 icebergs that represent a significant hazard 

 to transatlantic shipping. In addition, IIP 

 may not necessarily merge all reported 

 targets into its database: sightings of 

 targets outside MP's area of responsibility 

 and coastal icebergs are usually not 



merged as they represent little threat to 

 transatlantic shipping. Thus, total merged 

 targets is not necessarily an objective and 

 unbiased measurement from year to year. 



Admittedly, season length is related 

 to icebergs south of 48'N, as Commanders 

 of the International Ice Patrol consider this 

 measurement in decisions on when to 

 open and close seasons. Various authors 

 have discussed the appropriate metric for 

 ice season severity (Alfultis, 1987; Trivers, 

 1994; Marko, et al., 1994). Comparing 

 1999 to the past five years and measuring 

 the statistics against historical standards in 

 various papers, 1999 was remarkable in its 

 tameness, both in terms of its lack of an ice 

 season and in terms of the paltry number 

 of icebergs south of 48°N. A moderate 

 season length is defined as between 105 

 and 180 days. Extreme for icebergs is 

 defined as greater than 600 icebergs south 

 of 48°N (Trivers, 1994; Marko, et al., 

 1994). 



During an average season, IIP 

 prepares and distributes ice bulletins at 

 OOOOZ and 1200Z daily to warn mariners of 

 the southwestern, southern, and 

 southeastern limits of ice. U. S. Coast 

 Guard Communications Area Master 



Icebergs South of 48°N Since 1994 



500 



1000 

 Days 



1500 



2000 



Figure 6. Icebergs South of 48 N since 

 1994. excluding growlers, bergy bits and 

 radar targets. 



