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HARRIS, €. 
Met Office, FitzRov Road, Exeter, EX1 3PB, UK 
DVEN IE 
The Global Coupled Monitoring and Forecasting Centre (GLO- 
CPL) provides a single product in the CMEMS catalogue 
which differs from the other near-real-time global physical 
products in that the marine forecasts are delivered from the 
NEMO ocean component of a coupled ocean-atmosphere 
system. Details of this system and how it is initialized have 
changed significantly during Copernicus 1 (see below) and a 
further upgrade is nearly ready. However, ocean resolution 
remains at %° and there are still neither biogeochemical 
nor wave components in the system. Datasets delivered to 
users every day include: daily mean temperature, salinity, 
sea surface height, currents, mixed layer depth, and sea 
ice concentration and thickness (provided for both analysis 
and 10 days of forecast). Since July 2017, datasets have 
been complemented by: hourlv instantaneous sea surface 
height, sea surface temperature and surface currents. The 
analysis is updated the following day to make use of late- 
arriving observations. 
The operational GLO-CPL system has been upgraded 
regularly during Copernicus 1 to make the best use of both 
ıNn-situ and new satellite observations (particularly 
Sentinel-3) and ensure continued robustness. Following an 
upgrade introducing weakly coupled data assimilation to 
initialise the GLO-CPL forecasts, work during the later part 
of the period has focussed on a future transition to a 
combined ocean forecasting and weather prediction 
system. This will benefit from a higher resolution 
atmosphere, as well as providing potential opportunities 
for ensemble forecasting and, ultimately, more strongly 
coupled data assimilation. 
1. MAIN ACHIEVEMENTS 
At the start of Copernicus 1, the GLO-CPL product was 
delivered from two separate systems. Forecasts were 
provided from the Met Office GloSeab coupled seasonal 
forecast system (MacLachlan et al., 2015) while analyses 
came from the FOAM ocean-only system (Blockley et al., 
2014) which is the same system used to initialise the ocean 
ın GloSeab. These systems shared an almost identical 
ocean and sea ice science configuration (using the NEMO 
model coupled to the multi-thickness-category sea ice 
model CICE), with the FOAM global ocean configuration 
being forced (using CORE bulk formulae to specify the 
surface boundary condition) by Met Office globa 
atmospheric Numerical Weather Prediction (NWP) fields. 
"he NEMO global ocean configuration used the tripolar 
IRCA025 grid (with a 1/4° or 28 km horizontal grid spacing 
at the equator, reducing to 7 km at high southern latitudes, 
and -10 km iin the Arctic Ocean). The scientific configuration 
>f the Met Office Unified Model used as the atmosphere 
component of the GloSeab system was near identical to 
the NWP system providing the FOAM forcing fields, 
although the latter had a higher resolution (+17 km rather 
than -50 km). The main disadvantage of this system was 
*hat only the ocean forecast was delivered from an 
ınteractively coupled ocean-atmosphere system. This 
meant there was a high overhead in keeping uncoupled 
and coupled systems scientifically consistent to reduce the 
likelihood of initialisation shocks between uncoupled 
analyses and coupled forecasts. Control over diagnostics 
provided from the forecasts was also more limited due to 
the use of the GloSeab system. 
The most significant upgrade during Copernicus 1 was in 
July 2017 with the introduction of a ‘weakly coupled’ data 
assimilation system (Lea et al., 2015; Guiavarc'h et al, 
2019) to initialise the coupled forecasts. These are now 
oroduced from a new integrated operational svstem rather