NO. 4 TEMPERATURE VARIATIONS IN THE NORTH ATLANTIC IO5 



not cut the isobars at a constant angle (see fig. 7). But in all our 

 fields in the open ocean south of 50° north latitude between 20° and 

 40° west longitude and furthermore in the fields between 10° and 

 20° west longitude in the route Channel to New York, the angle 

 made by the average isobar directions for February with the iso- 

 therms for February varies only between 29° and 47° and is in the 

 mean 39°. 



According to theoretical computations, in consequence of the rota- 

 tion of the earth the direction of the currents which the wind 

 causes should be inclined at the angle of 45° to the wind direc- 

 tion. The agreement between our angle and this angle seems extra- 

 ordinarily good, since they differ by only 6°. The isotherms to 

 be sure do not follow exactly the same direction as the surface 

 current, for the latter has a more northerly direction. On the other 

 hand, the wind does no't move exactly in the isobar directions, but 

 somewhat to the left of this as is shown in chart, figure 8. 



We must keep in mind that it is not alone the wind relations of 

 February which have influence upon the temperature distribution 

 at the surface of the ocean in February, but probably also the wmd 

 relations in the previous time. It seems therefore more justifiable, 

 theoretically at least, to take the mean value, for example, of the 

 isobar directions in January and February to compare with the 

 February isotherms, and we have done this in the chart, figure 7, 

 and in plate i. With this modification we find that the angle between 

 the isobar directions and the isotherms is on the whole very nearly 

 the same as found above. In most of the stretch of free ocean sur- 

 face it comes to about 40°. It varies between 21° and 53°. The 

 mean is 37° instead of 39° as given above. 



In the most easterly part of the Atlantic Ocean near the Spanish 

 Peninsula, obviously the ocean currents set up by the wind are 

 influenced by the coast and the coastal topography. The average 

 isobar directions make another angle with the isotherms. Also in 

 the neighborhood of the American coast the isotherms are strongly 

 influenced by the Gulf Stream and the ocean bottom conditions, so 

 that one should not expect here so good an agreement between the 

 directions of the isobars and those of the surface isotherms, for 

 here the wind has less influence on the current. We find here, 

 accordingly, quite another angle between the isobar and the isotherm 

 directions. This is also partially the case in the fields south of the 

 Newfoundland Bank. However, it should not be overlooked that, 

 as figure 8 shows, the wind in this region blows much to the left 



