# Talk:Calchb.f

### From GHER

Alex: The buoyancy b is a non-linear equations of increments of T and S relative to a reference T (TREF) and S (SREF). Why are TREF and SREF are not fixed but computed in eau.f ?

Arthur : some test shows it as a problem ... This leads to underestimation of the stratification in my case (Black Sea, far from Mediterranean reference). 2 soultion : fix tref and sref to mediterranean value, or change the equation in calchb following the immplementation zone.. In fact, i think that even when i use Med references (coherent with the equation, but this equation is not linearized for Black sea watermass) i strongly underestimate the vertical gradient

for info

T_{REF,MED}= 12.8C,S_{REF,MED}= 38.4p.s.uT_{REF,BLACK}= 8.7C,S_{REF,BLACK}= 21.74p.s.u