INVESTIGATIONS INTO ICEBERG SIZE AND DISTRIBUTION 



The collection of data to assist in forecasting seasonal berg conditions 

 on the Grand Banks was continued. Bulletin No. 50 discussed the 

 interrelation of meteorological, climatological, and oceanographic 

 conditions, and land and bathymetric configuration on ice and berg 

 distribution. Additional data are presented on aerial berg surveys, 

 frost degree days of selected Baffin Island-Labrador-Newfoundland 

 coastal stations on the relative severity of the Grand Banks ice season, 

 the effect of mean sea level atmospheric pressure distribution on the 

 Grand Banks ice season, and correlation of these statistics to the 1965 

 and 1966 berg seasons. Refer to the U.S. Coast Guard Oceanographic 

 Report Series (CG-373) for oceanographic investigations into thei 

 drift of bergs as controlled by the currents of the Grand Banks andl 

 berg drift and deterioration studies as conducted by the U.S. Coasti 

 Guard Oceanographic Unit, Washington, D.C. 



NORTHERN AERIAL ICEBERG SURVEYS 



The aerial berg surveys conducted north of the Grand Banks am 

 including all of the western Baffin Bay-Labrador Sea area were con 

 tinned. As mentioned in Bulletin No. 50 of these series, the intent o: 

 these surveys is to accumulate statistical data on berg size and distri- 

 bution with respect to the months of the year and to correlate the berj 

 distribution with the other factors noted eai'lier in this publicatio: 

 Figures 2 through 20 show the distribution of bergs for the vario 

 areas observed. Figures 18 and 19 are the northern aerial berg surveyi 



In figures 18 and 19 the number of bergs distributed l)y latitud 

 noted in the lower righthand corner, comprise the number of ber 

 observed on the days noted plus an estimate, based on other inform 

 tion, of bergs south of the area covered by that particular flight. N 

 estimate is made of bergs that may not have been observed. Whei 

 during each flight visibility was reduced to less than 20 miles, rad: 

 was also used to detect targets. An inflight estimate was made of the 

 value of each radar target and depending on the circumstances the 

 target was marked as "radar target-possible berg" on the inflight 

 chart. Wlien field ice covered the sea surface and with reduced visi- 

 bility, the radar operator evaluated the radar blip as a berg or other 

 target. This was done by ^-iewing the shadow that fell behind the 

 target on the PPI scope. Leads in ice, hummocks, ridges, etc. in the 

 field ice do not present as distinguishable a characteristic blip as a 

 berg. However, use of radar to detect bergs located in field ice is 

 inexact. 



These surveys liave provided some insight into the distribution of 

 bergs as affected by the related factors. It is considered important 

 to continue this work until a sufficient amount of statistical data has 



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