Publication Date:
2017-04-04
Description:
One of the main objectives of the global ocean modelling activities
at Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC)
is the production of global ocean re-analyses over multidecadal
periods to reconstruct the state of the ocean and the large scale cir-
culation over the recent past. The re-analyses are used for climate applications
and for the assessment of the benefits of assimilating
ocean
observations on seasonal and longer predictions.
Here
we present the main characteristics of an optimal interpola-
tion
based assimilation system used to produce a set of global ocean
re-analyses
validated against a set of high quality in situ observa-
tions
and independent data. Differences among the experiments
of
the set are analyzed in terms of improvements in the method
used
to assimilate the data and the quality of observations them-
selves.
For example, the integrated ocean heat content, which can
be
taken as an indicator of climate changes, is examined to detect
possible
sources of uncertainty of its long-term changes. Global and
basin
scale upper ocean heat content exhibits warming trends over
the
last few decades that still depend in a significant way on the
assimilated
observations and the formulation of the background
covariances.
However, all the re-analyses show a global warming
trend
of the oceanic uppermost 700 m over the last five decades
that
falls within the range of the most recent observation-based
estimates.
The largest discrepancies between our estimates and
observational
based ones are confined in the upwelling regions of
the
PacificandAtlanticOceans.Finally,theresultsshow that the climatological
heat and salt transports as a function of latitude also
fall
within the range of the estimates based on observations and
atmospheric
re-analyses.
Description:
The
authors wish to thank the Centro Euro-Mediterraneo per i Cambiamenti Climatici for its financial and scientific support of some of the activities presented in this work. The implementation and the following
improvements of the global ocean assimilation system were carried out in the framework of the ENACT(EVK2-CT2001-00117)and ENSEMBLES(GOCE-CT-2003-505539)projects.
Description:
Published
Description:
341– 366
Description:
3.7. Dinamica del clima e dell'oceano
Description:
JCR Journal
Description:
partially_open
Keywords:
Data assimilation
;
Global ocean
;
Numerical models
;
Climate
;
03. Hydrosphere::03.01. General::03.01.01. Analytical and numerical modeling
;
03. Hydrosphere::03.01. General::03.01.03. Global climate models
;
03. Hydrosphere::03.01. General::03.01.04. Ocean data assimilation and reanalysis
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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