function [rho_n]=rho_not(S,T,c)
% B Barrett 1 Feb 2010
% Lab 2
%
% Computes the density for sea water at one standard 
% atmospheric pressure, i.e. the ocean surface, per
% Pond and Pickard's "Introductory Dynamical Oceanography", 2nd Ed.
%
% Variables:
%   
%   rho_n = 'rho not' = density of sea water at surface in kg/m^3
%
% Required inputs:
%       S= salinity in practical salinity units 
%       T = Temperature in degrees Celsius
%       c = array of coefficients for the density calculation
%
%calculate the density at the surface
%

rho_n = c(1) ...
+ c(2).*T.^2 + c(3).*T.^4 ...
+ c(4).*S + c(5).*S.*T.^2 ...
+ c(6).*S.*T.^4 + c(7).*T.*S.^(3/2) ...
+ c(8).*S.^2 + c(9).*T ...
+ c(10).*T.^3 + c(11).*T.^5 ...
+ c(12).*T.*S ...
+ c(13).*S.*T.^3 + c(14).*S.^(3/2) ...
+ c(15).*T.^2.*S.^(3/2);

%end function