INTRODUCTION 



An analytical model was developed to determine the coastal "sea current" 

 as given in the National Search and Rescue (SAR) Manual (CG-308) . In the SAR 

 Manual, "sea current" is characterized as the "permanent" large scale flow that 

 one might determine from available current atlases. The model specifically 

 describes the steady state non-tidal coastal current in the New York Bight 

 where SAR cases are numerous and atlas data inadequate. 



The momentum balance considered is steady, non-accelerated, and hydrostatic. 

 Longshore pressure gradients are neglected. The Coriolis parameter, f, and 

 vertical momentum exchange coefficient. A, are assumed constant. The governing 

 equations resemble the formulation of Welander (1957) , with his limitation of 

 constant density removed by including a constant cross-shelf density gradient. 



An analytical solution to the governing equation (essentially a second 

 order differential equation) is found \,y applying the appropriate boundary 

 conditions. These conditions include assuming that the surface wind stress is 

 proportional to the surface velocity shear, and that the velocity at the bottom 

 boundary vanishes. The solution is a relationship between wind stress, cross- 

 shelf density gradient, sea surface slope, and velocity. A form of the contin- 

 uity equation is then used to obtain the sea surface slope in terms of the wind 

 stress and cross-shelf density gradient. The solution is now a single relation- 

 ship between wind stress, cross-stream mean density gradient, and velocity. 



