Initial conditions for this problem are a quiescent free surface and velocity field, and no stratification.
Stratification can be turned off by setting
beta to zero in
suntans.dat. This is because the equation
of state, as given in
suntans/main/state.c is linear and only requires
beta to convert from
salinity to density. Note that when
beta is zero, advection of salinity is also not computed, which can
save on computation time.