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Short-term climate variability

Objective

To study those atmospheric processes which are believed to be
mostly either responsible for, directly caused by, or linked
with short-term climate variability, i.e. midlatitude weather
regimes, blocking, storm-tracks, tropical 30-to-60-day
oscillation, monsoons and the ENSO phenomenon.
To investigate the intrinsic predictability of such processes
and diagnose the ability of GCMs used for Anthropogenic Climate
Studies to represent and reproduce such processes with the
correct characteristics and space-time frequency.


Short-term climate variability (STCV) is here defined as
spanning time scales from the month to the interannual
timescale and these are the timescales directly addressed in
this research project. Low-frequency atmospheric variability
(LFV) is here defined as spanning time scales from a few days
to a few weeks.

The role of atmospheric LFV in inducing STCV will be
investigated by means of theoretical studies and by analyzing
both observed and model data. This will require the
development (or the refinement) of a number of techniques.
Such techniques include improved quantitative objective
algorithms capable of identifying those large-scale flow
patterns typical of atmospheric LFV and statistical analysis
tools (essentially EOF and cluster analysis). Such algorithms
will allow the use of atmospheric LFV as a diagnostic tool to
assess the ability of GCMs to represent current climate, by
comparing observed LFV with Climate GCM-produced LFV.

An essential further step will be to either produce or acquire
extended model integration to be analyzed and assessed using
the above diagnostic tools. Both such avenues will be pursued
in this project. Some integrations will be produced by project
contractors, others will be acquired from Max-Plank Institut
fuer Meteorologie, Hamburg, FRG.

Changes in space and time characteristics of atmospheric LFV
caused by greenhouse gases increases (of the IPCC scenario
type) will then be measured in extended integrations of
Climate-GCMs and the sensitivity of simulated climate to model
formulation (resolution and physical parametrisations) will be
assessed.

Ultra-low frequency (interdecadal) atmospheric variability
will also be investigated by means of more simplified (Quasi-
Geostrophic) models.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Università degli Studi di Bologna
Address
Via Irnerio 46
40126 Bologna
Italy

Participants (4)

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE
France
Address
Ecole Polytechnique
91128 Palaiseau
DANISH METEOROLOGICAL INSTITUTE
Denmark
Address
100,Lyngbyvej 100
2100 Koepenhagen
European Centre for Medium-range Weather Forecasts - ECMWF
United Kingdom
Address
Shinfield Park
RG2 9AX Reading
Ludwig-Maximilians-Universität München
Germany
Address
Theresienstraße 37
80333 München