function f = coriolis( lat )
% CORIOLIS - Returns f for latitude (degrees)
% f = coriolis( lat )
%
% Input
%   lat - Latitude (degrees)
% Returns
%   f - Coriolis frequency (radians/s)
% BigOmega = (2*pi)/86164.09; % 2pi / seconds in sidereal day 
BigOmega = 7.292115e-5; % Earth rotation rate (rad/s) Kantha & Clayson p.842
f = 2*BigOmega .* sin( lat*pi/180 );