NO. 4 TEMPERATURE VARIATIONS IN THE NORTH ATLANTIC 297 



vice versa {c. g., in the regions of the NE trade winds outside north- 

 western Africa (cf. fig, no, III, IV). But in regions where an 

 increased activity of the barometric centers of action will produce 

 more warm winds the effect will be higher temperatures, and vice 

 versa (e. g., in Norway). 



Taking it generally, we may therefore expect that in regions where 

 the normal annual temperature is comparatively high for its lati- 

 tude (or at least higher than in neighboring regions) an increased 

 atmospheric circulation should, as a rule, have a warming effect, 

 while in regions where the normal annual temperature is lower 

 than that of the latitude it should have a cooling effect. 



In figure iii we have given the temperature curves, smoothed by 

 twelve-month means, for several stations from different regions of 

 the globe. The broken curves are inverted, while the others are 

 direct. The curves show departures from normals that for the 

 stations of curves VIII-X are computed for the thirty years 1877- 

 1906. 



At the top of the figure we have reproduced the curves of the 

 barometric departures, smoothed by twelve-months means, at Batavia 

 (curve I, inverted) at Ponta Delgada (curve II), and for the dif- 

 ference between the pressure maximum (Azores) and the pressure 

 minimum (Icelandic) of the North Atlantic (curve III). 



In Norway there are prevailing southwesterly winds during the 

 year, and the temperature is much higher than for any other region 

 of corresponding latitudes. This is due to the warm oceanic cur- 

 rent outside its coasts and to the prevailing winds. The fluctuations 

 in the temperature of Norway (curve IV) agree remarkably well 

 with the barometric variations at Ponta Delgada (curve II) as also 

 with the variations of the pressure gradient of the North Atlantic 

 (curve III, and with the inverse barometric variations at Styk- 

 kisholm (see figs. 91, 95, and 108), as also with the inverse variations 

 of the pressure gradient in the region of the NE. trade winds (see 

 fig. no, I and III). 



What a decisive influence the situation of a station, in relation to 

 the barometric center of action, has on the nature of its temperature 

 variations is demonstrated by the striking difference between the 

 temperature variations at stations lying no farther apart than the 

 Azores on the northern side of the Azores pressure maximum and 

 Madeira on its southeastern side, as well as the Cape Verde Islands 

 to the south of it. The temperature in the Azores (Angra and 

 Ponta Delgada) fluctuate as a rule inversely as the temperature in 

 20 



