FOAM
405
Assimilation of temperature and salinity data produces markedly better
salinity statistics than assimilation of just salinity data and slightly better
temperature statistics than assimilation of just temperature data. These
results may be explained by the impact of the assimilation on the advecting
velocity field but this hypothesis has not been verified in detail.
Figure 3. Impact of assimilating Argo data on FOAM global model: no assimilation - full
line; temperature data only – dotted; salinity data only - dot dash; temperature and salinity
data – dashed.
The impact of the representation of the background error covariance on
the effectiveness of the data assimilation is also of considerable interest as
differences between most assimilation schemes can be interpreted as
differences in the representation of the background error covariance. Figure