function [UserVar,rho,rhow,g]=DefineDensities(UserVar,CtrlVar,MUA,time,s,b,h,S,B)
Define ice and ocean densities, as well as the gravitational acceleration.
[UserVar,rho,rhow,g]=DefineDensities(UserVar,CtrlVar,MUA,time,s,b,h,S,B)
rhow : ocean density (scalar variable) rho : ice density (nodal variable) g : gravitational acceleration
rho=918+zeros(MUA.Nnodes,1) ;
rhow=1028;
g=9.81/1000;
end