Estimation of positive sum-to-one constrained zooplankton grazing preferences with the DEnKF: a twin experiment 1Nansen Environmental and Remote Sensing Center, Norway
08 Aug 2012
2Bjerknes Center for Climate Research, Norway
3Institut des sciences de la mer, Université du Québec à Rimouski, Canada
Received: 28 February 2012 – Published in Ocean Sci. Discuss.: 19 March 2012 Abstract. We consider the estimation of the grazing preferences parameters of
zooplankton in ocean ecosystem models with ensemble-based Kalman filters.
These parameters are introduced to model the relative diet composition of
zooplankton that consists of phytoplankton, small size-classes of zooplankton
and detritus. They are positive values and their sum is equal to one.
However, the sum-to-one constraint cannot be guaranteed by ensemble-based
Kalman filters when parameters are bounded. Therefore, a reformulation of the
parameterization is proposed. We investigate two types of variable
transformations for the estimation of positive sum-to-one constrained
parameters that lead to the estimation of a new set of parameters with normal
or bounded distributions. These transformations are illustrated and discussed
with twin experiments performed with the 1-D coupled model GOTM-NORWECOM with
Gaussian anamorphosis extensions of the deterministic ensemble Kalman filter
Revised: 18 June 2012 – Accepted: 28 June 2012 – Published: 08 August 2012
Citation: Simon, E., Samuelsen, A., Bertino, L., and Dumont, D.: Estimation of positive sum-to-one constrained zooplankton grazing preferences with the DEnKF: a twin experiment, Ocean Sci., 8, 587-602, doi:10.5194/os-8-587-2012, 2012.