Stochastic estimation of biogeochemical parameters of a 3D ocean coupled physical-biogeochemical model: Twin experiments

► 3 biological rates assumed stochastic in a 3D ocean physical-biogeochemical model. ► Model response nonlinear and non-Gaussian (ensemble of 200 members, 30 days). ► Parameter estimation in Kalman filter framework: linear and nonlinear (anamorphosis). ► Variance reduced using anamorphosis rather than linear analysis (37 on 39 parameters). ► Anamorphosis introduces an objective error norm for biogeochemical variables.