Table F-1. TIMES OF ICEBERG SIZING MEASURMENTS. Dates and times to the nearest hour when 

 icebergs were sized are listed. Iceberg numbers refer to the sequential numbering system that IIP uses to 

 track individual icebergs during the course of the ice season. 



photograph taken, and the scalar 

 dimensions recorded. (Scalar 

 dimensions were converted to 

 length and height after all the field 

 work was completed.) At the end 

 of the second pass, the ice 

 observers collectively estimated 

 the iceberg's maximum height and 

 length. No visual cue, like a ship's 

 boat or another vessel, was 

 available to help size the iceberg; 

 only the horizon, when weather 

 permitted. Neither stadimeters nor 

 sextants were used. 



Iceberg size measurements were 

 conducted within 1900 m of each 

 iceberg; distances for each 

 observation are listed in Table F-2. 

 These distances were dependent 

 upon weather and the ability to 

 view/measure the entire face of 

 the iceberg through the reticulated 

 binoculars. 



130 



STUDY FINDINGS 



Thirty-one visual estimations of 

 both height and length were 

 compared to measured dimen- 

 sions. The results indicated that 

 the trained observer tended to 

 underestimate both length and 

 height. 



All but one of the visually-esti- 

 mated lengths were less than the 

 measured length; see Figure F-1 a. 

 For this set, a linear regression 

 indicated the estimated length was 

 about 56 per cent of the measured 

 length. The data set's linear 

 correlation was 0.72. 



The observers better estimated 

 height. All but seven of the 

 visually-estimated heights were 

 less than the measured height; 

 see Figure F-1 b. For this set, the 



regression indicated the estimated 

 height was about 66 per cent of 

 the measured height. The correla- 

 tion was 0.81. 



CONCLUSIONS 



Visual observations made close to 

 medium-sized, non-tabular 

 icebergs without the aid of meas- 

 urement devices (i.e. stadimeters, 

 sextants, or reference objects) 

 may underestimate their size. 

 Therefore, if an iceberg appears 

 on the txjrder between two size 

 categories, the IIP recommends 

 assigning the iceberg to the larger 

 of the two size categories. Given 

 the difficulty in properly estimating 

 size, IIP encourages the use of all 

 measurement devices at one's 

 disposal. 



