Wednesday, 16 January 2002: 4:15 PM
The importance of salinity in the assimilation of temperature observations in the tropical Pacific Ocean
Assimilation of temperature data has improved the quality
of ocean state estimates used to initialize the coupled
model forecasts conducted by the NASA Seasonal-to-
Interannual Prediction Project (NSIPP).
Nonetheless, deficiencies in the density field are still
present. One of the main reasons for such deficiencies is
related to the fact that salinity is not analyzed and its
effect on the density field is not negligible.
In this work we analyze how the ocean initial conditions
are affected when not only temperature but also salinity
is updated at assimilation times. However, only observed
sub-surface temperature is used. Salinity increments are
derived from a scheme that uses the analyzed temperature
along with the model temperature and salinity to preserve
the model's water masses.
Results show that the salinity scheme is effective at
maintaining the halocline and thermocline structures
especially in tropical regions, structures that would
otherwise be corrupted by spuriously enhanced vertical
mixing caused by the univariate assimilation of subsurface
temperature. The effect of these subsurface modifications
on seasonal forecasts will be discussed.
Supplementary URL: http://janus.gsfc.nasa.gov/~troccoli