I think that there is a small error in the available_diagnostics.log output file. The line for the stratification reads: 278 |DRHODR | 20 |SM LR |kg/m^4 |Stratification: d.Sigma/dr (kg/m3/r_unit) where "SM" means Scalar on C-grid Mass point. However my calculations suggest that it is calculated on a C-grid W point. Jeff