earth to permit the resolution of icebergs by photography. The next 

 possibility might be an earth-orbiting satellite which would observe 

 the ice conditions each time it passes over the Grand Banks. In order 

 to permit resolution of small icebergs, the altitude must be so low that 

 only a portion of the area of responsibility could be swept. The 

 weather must be unusually excellent as cloud cover is presently an 

 insurmountable barrier to satellite iceberg observing. There is also 

 the cost to be considered for the performance obtained. It has been 

 estimated that a single satellite would cost more than it presently 

 costs to operate the entire Ice Patrol for an ice season. At best a satel- 

 lite could be a minor assistance to aircraft for ice surveillance and its 

 cost does not jusify its use for the near future. 



It has been explained why the ice limits cannot practicably be con- 

 tinuously observed and guarded. Thus during the interval between 

 successful observations of the ice limits by aerial reconnaissance it 

 becomes necessary to forecast the ice conditions. The forecasting is 

 required in order to inform shipping of the best estimate of the ice 

 conditions twice each day. Forecasting the movement of ice between 

 observations is also an essential ingredient in ice observing and guard- 

 ing ice limits whether by ship or aircraft. The more accurate the fore- 

 casting, the more effective are the services to shipping. Accurate fore- 

 casting requires frequent and accurate ice observing and an intimate 

 knowledge of icebergs, their environment, and the forces that affect 

 their drift and deterioration. There is a need for short-range fore- 

 casting of ice conditions from day to day and also for long-range 

 forecasting, weekly, monthly, and seasonal. Short-range forecasting 

 is more urgently required as the accuracy of ice condition information 

 disseminated daily to shipping is dependent upon same. Also effective 

 flight planning is dependent upon accurate forecasting of ice con- 

 ditions each day. 



There are four basic forecasting tools that are available to the Ice 

 Operations Officer. The chart of dynamic topography, based on a 

 recent oceanographic survey depicting geostrophic current in berg 

 areas on the slopes of the Grand Banks and vicinity, is used to forecast 

 movement of icebergs due to permanent type currents. A chart of 

 dynamic topography only partially covers the area of responsibility 

 and it loses its value with time. It is estimated to be of little or no 

 value within two weeks. Normal current charts are used to estimate 

 iceberg drift, in areas not covered by a recent survey. The average 

 wind in berg areas is obtained from Fleet Weather Facility, Argentia. 

 Newfoundland twice daily so that iceberg drift due to wind can be 

 estimated. The above tools are used to quantitively predict the move- 

 ment of ice, but deterioration must also be forecast. The deterioration 

 of ice is imperfectly understood and forecasts are limited to qualitative 

 guesses based on estimated sea conditions due to wind and estimated 



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