Ocean Sci., 8, 587-602, 2012
www.ocean-sci.net/8/587/2012/
doi:10.5194/os-8-587-2012
© Author(s) 2012. This work is distributed
under the Creative Commons Attribution 3.0 License.
Estimation of positive sum-to-one constrained zooplankton grazing preferences with the DEnKF: a twin experiment
E. Simon1,2, A. Samuelsen1,2, L. Bertino1,2, and D. Dumont3
1Nansen Environmental and Remote Sensing Center, Norway
2Bjerknes Center for Climate Research, Norway
3Institut des sciences de la mer, Université du Québec à Rimouski, Canada

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 (DEnKF).

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.
 
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