Physical and biological modeling in the Gulf Stream region: I. Data assimilation methodology

Physical and biological data are assimilated into a time-evolving, mesoscal e-resolution three-dimensional (3-D) ocean model using optimal interpolatio n. Simulations are conducted in the Gulf Stream region during the BIOSYNOP/ Anatomy of a Meander Experiment in September-October of 1988. Physical data assimilation only or biological data assimilation only resulted in misalig nment of the physical and biological fronts, causing spurious cross-frontal fluxes of biological quantities. Assimilation of both physical and compati ble biological fields was necessary for adequate equilibration of the simul ated fields. The resulting combined 4-D fields substantially extend the val ue of the observations alone. A technique is presented for deriving the nec essary, dynamically consistent 3-D physical and biological field estimates from data for initialization and assimilation into time-evolving model simu lations. (C) 2000 Elsevier Science Ltd. All rights reserved.