Publikationsdatum:
2013-11-29
Beschreibung:
The Forecast Ocean Assimilation Model (FOAM) is an operational ocean analysis and forecast system run daily at the Met Office. FOAM provides modelling capability in both deep ocean and coastal shelf seas regimes using the NEMO ocean model as its dynamical core. The FOAM Deep Ocean suite produces analyses and 7 day forecasts of ocean tracers, currents and sea ice for the global ocean at 1/4° resolution and at 1/12° resolution in the North Atlantic, Indian Ocean and Mediterranean Sea. Satellite and in-situ observations of temperature, salinity, sea level anomaly and sea ice concentration are assimilated by FOAM each day over a 48 h observation window. The FOAM Deep Ocean configurations have recently undergone a major upgrade which has involved: the implementation of a new variational, first guess at appropriate time 3D-Var, assimilation scheme (NEMOVAR); coupling to a different, multi-thickness-category, sea ice model (CICE); the use of CORE bulk formulae to specify the surface boundary condition; and an increased vertical resolution for the global model. In this paper the new FOAM Deep Ocean system is introduced and details of the recent changes are provided. Results are presented from 2 yr reanalysis integrations of the Global FOAM configuration including an assessment of forecast accuracy. Comparisons are made with both the previous FOAM system and a non-assimilative FOAM system. Assessments reveal considerable improvements in the new system to the near-surface ocean and sea ice fields. However there is some degradation to sub-surface tracer fields and in equatorial regions which highlight specific areas upon which to focus future improvements.
Print ISSN:
1991-9611
Digitale ISSN:
1991-962X
Thema:
Geologie und Paläontologie
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