Satellite altimetry data assimilation in the OCCAM global ocean model

As part of the European AGORA programme we have been assimilating TOPEX/POS EIDON altimeter data into the Southampton Oceanography Centre's high resolu tion (1/4 degree, 36 level) global ocean model (OCCAM). The assimilation me thod used is that of Cooper and Haines, a dynamically based method which co nserves water properties on isopycnal surfaces. Results of a one-year, 1993 , run of this model, driven by ECMWF B-hourly winds and assimilating 10-day mapped TOPEX/POSEIDON data are presented. A method to improve the model me an sea level for use in altimeter assimilation is described and implemented in the Gulf Stream and Kuroshio separation regions. Results demonstrate th e model's ability to adjust to this new mean sea surface and to also propag ate the assimilated altimeter signal realistically in time, an essential ch aracteristic if ocean forecasting is to be attempted. (C) 1999 Elsevier Sci ence Ltd. All rights reserved.