prevailing winds in the southwest Atlantic are generally southerly as compared to 

 the winter westerlies. 



Since the May and November mean pressure maps are approximately 

 intermediate between Figures 1 and 2, it seemed unnecessary to include these 

 charts. 



As seen on the daily weather maps, the change from the summer to the 

 winter type of circulation does not take place gradually through the intermediate 

 season, but the circulation pattern varies erratically from one type to the other for 

 short periods. As the winter season approaches, the winter circulation pattern is 

 more frequently present, the summer pattern less frequently. 



3. Ocean Currents in Winter. 



The principal winter ocean currents are illustrated in Figure 3 — extracted 

 from Schott.^ The strength of the currents is indicated by the closeness of the lines 

 on the chart. It will be observed that the general distribution of the ocean currents 

 conforms closely with the prevailing winds which are given in Figure 1. This close 

 agreement results from the fac^ that the ocean currents are maintained by the 

 stresses which the winds exert' on the sea surface. The principal ocean currents 

 may be summarized as follows: 



(1) North Equatorial Current. This current flows from east to west in the 

 trade- wind region. 



(2) Gulf Stream System. This system includes the Florida Current, the 

 Gulf Stream and the North Atlantic Current. This circulation of warm water 

 extends as far north as northern Norway, where it is known as the Norwegian 

 Current. 



{3) East Greenland Current. This is a cold current which branches into the 

 East Iceland Arctic Current and the northward flowing West Greenland Current. 



(J/.) Labrador Current. The W^est Greenland Current reverses its direction 

 in the vicinity of Davis Strait and joins the cold water drainage from Baffin and 

 Hudson Bays. This cold southward flowing current along the coast of Newfound- 

 land and the northeast coastline of the United States is known as the Labrador 

 Current. It is evident from Figure 3 that this cold current results in the presence 

 of icebergs and drift ice to 40° N in the western Atlantic in late spring. 



The change from winter to summer in the general features of the ocean 

 currents is relatively unimportant; consequently no diagram of summer ocean 

 currents has been included. 



4. Sea Surface Temperature. 



Isotherms for the sea surface are shown in Figures 4-7. On these charts 

 two sets of isotherms have been drawn, corresponding to two difi^erent sources of 

 data, viz., the Climatic Charts of the Oceans^ and the "Meteor" Expedition data.^ 

 The full lines, which were obtained from a great number of observations, are prob- 

 ably more reliable. The "Meteor" data cover the brief period from 1925 to 1927, 

 but it gives a good indication of the temperature north of 60° N. 



It will be seen from the maps that, in all seasons of the year, there is warm 

 water on the western side of the ocean in low latitudes and on the eastern side in 

 high latitudes. This general distribution of sea surface temperatures is a result of 

 the Gulf Stream System and of the Canaries Current oft' the coast of North x\frica. 

 It is further evident that east and south of Newfoundland, where the Labrador and 

 Gulf Stream Currents are in close proximity, there is a pronounced temperature 



