The overall objective of the project is to perform observational
studies and numerical simulations to investiagte and understand
the nature of the decadal and interdecadal variability of the
The importance of the decadal and interdecadal segment of the
natural climate variability has been recently recognized by the
World Climate Research Program (WCRP) by sponsoring a new
research initiative, CLIVAR, aimed at time scales from the season
to a century. Such time scales are of crucial importance when
discriminating natural climate changes from those that may be
caused by human intervention. This project responds to this
initiative by concentrating on two major components of the
decadal variabilty, the oceanic decadal variability, seen in the
thermohaline circulation and the SST, and the atmospheric
response to the SST, with a special emphasis on precipitation and
The work is centered around numerical experiments with a
hierarchy of General Circulation Models (GCMs) and observational
studies. The investigations can be divided into the following
Assessment of the reliability of present atmospheric GCMs of
simulating present climate variations on the decadal timescale
and in particular the precipitation variability over the
European/Mediterranean (EM) region and over the Tropics, with
special emphasis on the Sahel.
Evaluation of the reproducibility of the simulations by
performing ensemble integrations.
Model validation through comparison with the observed decadal
fluctuation of precipitation established through supporting
Investigation of the relationship between interannual and
intraseasonal variability (QBO, ENSO, Monsoon ) on the decadal
time scale. Particular emphasis will be placed on the
interaction between tropics and extra-tropics.
Investigation of the nature and dynamics of the decadal
variability of the thermohaline circulation and its relation to
the SST variability.
Determination of the predictability of the decadal variability.
Funding SchemeCSC - Cost-sharing contracts
3730 AE De Bilt
RG12 2SZ Bracknell
RG6 2AU Reading / Silchester