IMPLEMENTING A 3D-VAR DATA ASSIMILATION SYSTEM IN THE MET OFFICE’S OCEAN FORECASTING MODEL

摘要

We are currently updating the data assimilation scheme in NEMO to the 3D-VAR system, NEMOVAR. This is replacing our current analysis correction data assimilation scheme in the operational system this Autumn. NEMOVAR is a multivariate incremental variational data assimilation scheme. We will describe the implementation of NEMOVAR at the Met Office and will give an overview of the system. We will discuss how the different data types are assimilated in a coherent way using the balance relationships and will describe the specification of the error covariances. We will also show results from a NEMOVAR reanalysis and we will compare these to observations and results from our previous system.