COMPARISON OF ICEBERG INCIDENTS AND SEA ICE 



EXTENT 



c 



■D 

 O 



c 



20 

 18 

 16 

 14 

 12 

 10 



8 



6 



4 



2 



J 



"7 per. Mov. Avg. (Sea Ice) 

 7 per. Mov. Avg. (Incidents) [i 40000O 



^./swXA- 



500000 



450000 E 

 :^ 



350000 r 

 300000 I 

 250000 "J 



0) 



200000 -^ 

 150000 (55 

 100000 



1810 



1860 



1960 



1910 



Year 



Figure 4: Comparison of iceberg incidents vvitti the deduced sea ice extent (Hill, 

 1998) using 7 year nioxing averages 



severity since about 1930, but there are trends to more severe conditions around 1950 and 

 again in the '70's and ■90's. The cyclical variation of ice extent is discussed in Hill & Jones. 

 1990. It is interesting to note thai in these cases there was no real corresponding increase in 

 collisions. Figure 5 shows the period 1900 tt) present in more detail and uses the annual 

 iceberg count as provided by the IIP. The steady decline in incidents from the early I910's 

 through the 1920's is evident. Thereafter, the annual number of incidents remain at a low 

 level often reflecting the occurrence of icebergs but not the magnitude. It is tempting to see 



COMPARISON OF ICEBERG INCIDENTS WITH NUMBER OF 



ICEBERGS 



-r 2500 



(A 



C 



o 



is 



o 

 o 



1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 



Year 

 Figure 5: Comparison of iceberg incidents with the IIP annual iceberg count south of 4S N 



61 



