SECT. 2] 



LAKGE-SCALE INTERACTIONS 



281 



TREND OF AVERAGE ANNUAL SEA TEMPERATURE "C 

 FROM 1890-97 TO 1926-33 



STREAMLINES MARK STEM AND BRANCHES OF 

 THE GULF STREAM SYSTEM 







V 



V 



ao 



f^H 



^^N 



Fig. 88. Streamlines of the Gulf Stream system (heavy lines with arrow-heads) and iso- 

 pleths of temperature change (°C) of annual sea-surface temperature from 1890-97 

 to 1926-33. Positions of present weather ships marked with capital letters. (After 

 Bjerknes, 1959, Fig. 1. By courtesy of the author and the publishers.) 



Table XXV 



Pressure Gradients and Corresponding Geostrophic Winds along Selected 



Profiles in the North Atlantic for Two Periods 



(after Bjerknes) 



represents that in the zonal westerlies. The development of a pressure difference 

 between Bermuda and Hatteras suggests the addition of a prevailing southerly- 

 wind and stress component off the United States east coast between periods. 

 Although there is unfortunately little direct wind data to confirm or modify 

 these figures, the large changes in surface stress deduced here would be very 



