3. COMPONENTS OF SURFACE CURRENTS 



Surface currents are caused and influenced simultaneously by a 



number of forces which vary independently from each other in space 



and time. If one neglects the special effects due to variation in 



depth, coastal configuration, runoff, etc. , the current vector at a 



given location, time and depth below the surface {^y-.^^ J can be 



given as the resultant of the following components: 



W = w + w + W, + W. (1) 



xyzt c w 1 t 



where W is the permanent flow (thermo-haline gradient current or 

 c 



"characteristic current" as used by Palmen (1930) and Hela (1952)), 

 \V is the current due to transport by wind and waves, Wj is the 

 periodic part of the inertia current and \v is the periodic part of 

 the tidal current. 



The computations which will be described here cover a period of 

 24 hours, and it will be assumed that semidiurnal and diurnal tidal 

 components will equal out and can be neglected. In addition, inertial 

 eddies will not be considered because the available quantitative infor- 

 mation about their behavior does not warrant their inclusion in this 

 simple technique. The two components which this study will attempt 

 to evaluate are thus the "characteristic " or permanent transport and 

 the transport due to wind and waves . 



