184 



MAEIOX EXPEDITIOX TO DAVIS STRAIT AXD BAFFIX BAY 



of these weather-majD values with the values of icebergs, shows that 

 an excess of air over the northern Xorth Atlantic has been reflected 

 either in a very light, or at least a moderately light, iceberg season 

 off Xewfoundland during the following spring. The opposite type 

 of pressure distribution is unmistakeable in showing a greater num- 

 ber of bergs than normal, but it does not permit of subgrouping. 

 The plus type of pressure map. in other words, exhibits a higher 

 correlation Avith poor iceberg years than does the minus type with 

 correspondingly rich years. This indicates that there are other in- 

 fluences at work, such as variations in the air temperatures and in the 

 water temperatures in the far north ; variations in the precipitation, 

 or perhaps sporadic phenomenon, such as an ice jam in the Arctic 

 Archipelago. 



It Avas found that pressure differences between various points 

 furnished the most useful values for purposes of correlation, because 

 in this method there is no room for the per.sonal bias which may 

 enter when charts are classified according to the types. "We corre- 

 lated first the annual variations of icebergs past Newfoundland with 

 the pressure gradient for the previous summer over the ice fjords 

 of west Greenland, the actual values employed being the pressure 

 differences, Jacobshavn minus Upernivik. as obtained from the 

 previouslv constructed isobaric maps of the Davis Strait region, 

 1880-1920. 



The months were then examined separately as follow: 



Tlie negative value of the correlation is in the right direction, 

 namely, that with ]H'essure lower at Jacob.shavn than I']iernivik. the 

 winds are directed offshore, and therefore tend to drive an abnormal 

 number of icebergs into the current that eventually bear them past 

 Newfoundland. The magnitude of the correlations are. however, 

 insignificant and therefore we must conclude contrary to .Mccking 

 (1J)0()). that ahliougli the offshore summer gradient is real, it is 

 uevei'tlieless of little ini])ortance, so far as effecting the dispeisal of 

 bergs south of Ncwfouiidland. 



I 



