CLIMATE AND THE DISTKIBUTION OF MARINE ANIMALS 



301 



that the winters have been generally milder since 

 1932 and that a significant warming has occurred 

 since 1945. 



RELATION BETWEEN AIR AND SEA 

 TEMPERATURES 



Many sources of evidence indicate that tlie 

 warming of the air began perhaps as early as 1850 

 and that air temperatures have been at a generally 

 high level since 1900. Data on sea temperatures 

 cover, for tiie most part, periods since 1900. 

 Thus, we may be observing fluctuations in sea 

 temperatures at a higher level than occurred in 

 the earlier period. By e.xamining the correlation 

 between air and sea temperatures, the likelihood 

 of this possibility may be determined. 



The relation between Eastport air temperatures 

 and Boothbay Harbor water temperatures for the 

 month of January during the period 1906-49 is 

 illustrated in figure 10. The correlation coeffi- 

 cient is 0.658, which is highly significant. The 

 same relation using New Haven air temperatures 



is shown in figure 1 1 . The correlation coefficient is 

 0.610, also highly significant. The relationships 

 are not (juite good enough to predict with accuracy 

 the surface temperature from a given air tempera- 

 ture; however, the correlation is sufficiently high 

 to conclude that these air temperatures are a rough 

 index of the general level of surface water tem- 

 peratures. On this basis we can assume that win- 

 ter surface water temperatures prior to 1900 were 

 generally lower than after that date. 



Further confirmation of our conclusion that 

 changes in air temperatures for the period prior to 

 1900 are generally indicative of changes in sur- 

 face water temperatures is to be found in a series 

 of water temperature records for Eastport, Maine, 

 for the period 1878-87 (Moore 1898). These data 

 are compared with air temperatures for the same 

 period and with air and water temperatures at 

 Eastport for the period 1941-50 (table 2). The 

 general increase in air temperatures for each 

 month between the two periods is faithfully re- 

 flected in a corresponding increase in water tem- 

 peratures. 



o 



UJ 



D= 36 



< 



CC 34 



LU 



CL 



i^ 32 



DC 



LU 30 



I- 

 < 



^ 28 



5r^ 



°K- 



J I 1 I L 



J L 



J L 



J I I L 



J I L 



12 



14 



16 



8 



20 



22 



24 



26 



28 



30 



AIR TEMPERATURE F. 



FiciKE 10. — The relation between Eastport, .Maine, air temperatures and Boothbay Harbor. .Maine, water 



temperatures for the month of January, 1906-49. 



