INTRODUCTION 



This is the 67th in a series of annual reports on 

 the International Ice Patrol Service in the North 

 Atlantic. The U.S. Coast Guard conducted the 

 1981 International Ice Patrol service to observe 

 the southeastern, southern, and southwestern 

 limits of icebergs in the vicinity of the Grand Banks 

 of Newfoundland to inform international mariners 

 of the extent of the iceberg hazard. 



Commander, International Ice Patrol, who 

 reports to Commander, U.S. Coast Guard Atlantic 

 Area, directed the 1981 operations from the Inter- 

 national Ice Patrol Office located at Governor's 

 Island, N.Y. Ice Patrol personnel analyzed aerial 

 reconnaissance information and other ice and en- 

 vironmental data and prepared the daily ice 

 bulletins and facsimile charts for radio transmis- 

 sion to the maritime community. All Coast Guard 

 units deployed on Ice Patrol missions were under 

 the operational control of Commander, Interna- 

 tional Ice Patrol. 



Preseason flights in January, February, and 

 March 1981 determined the early season iceberg 

 distributions. Based on these flights, the 1981 

 reconnaissance season commenced on 13 March. 

 From that date until 24 July 1981, an Ice Recon- 

 naissance Detachment operated from St. John's, 

 Newfoundland, averaging a patrol every two days 

 over the Grand Banks. The reconnaissance season 

 was officially closed 27 July 1981. 



The historical current field used as the data base 

 to predict the drift of the icebergs in the Grand 

 Banks region was validated by tracking TIROS 

 Oceanographic Drifters (See Appendix A). 



During the 1981 season, only an estimated 63 

 icebergs drifted south of 48 degrees North. 

 Monthly estimates of icebergs which crossed that 

 latitude are shown in Table 1. 



TABLE 1 

 ESTIMATED ICEBERGS DRIFTING SOUTH OF 48 DEGREES NORTH 



1981 



AVERAGE 



1946-1981 



AVERAGE 



1900-1981 



SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG TOTAL 

 000000 48 10 5000 63 



