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WP1200/WP1300
Diagnostic analysis of
ensemble integrations performed under the PRISM (Predictability experiments
for the Asian summer monsoon) project. (in collaboration with CINECA,
ECMWF, UREDMY).
The dominant patterns of
interannual variability of the Asian summer monsoon circulation (as
simulated in the PRISM experiments) have been determined by means of
a SVD analysis of 850-hPa wind and rainfall in the region (60-120E,
40N-20S). The two leading SVD pattern resemble some of the dominant
variability patterns found in observational studies based on re-analyses
(Annamalai et al, MWR 1999; Sperber et al, QJRMS 2000). However, the
modelled distribution of variance is quite different from the observed
distribution, with a very large fraction (especially for the wind field)
accounted for by the first mode. This mode (which is associated with
a meridional shift of the TCZ in the Indian Ocean) shows a relatively
low degree of reproducibility in ensembles with observed SST, and the
agreement between ensemble-mean and re-analysis values of the correspondent
time-coefficient is poor. Conversely, the second mode (quite similar
to the observed composite in years of anomalous All-India Rainfall)
is strongly influenced by the ENSO cycle, and a good agreement is found
between the observed and ensemble-mean coefficient. An analysis of the
relationship between these interannual variability modes and the intraseasonal
variability of modelled rainfall (as deduced from 5-day mean field)
is under way.
WP5000
Collaboration with research
institutions in monsoon-affected countries.
Scientists from three institutions
interested in research collaborations under PROMISE (from Brazil, India
and the Philippines)ã have been
nominated Associate Members of ICTP in 2000. This entitles them to a
number of funded visits (each lasting about 2-3 months) to ICTP in the
next six years.
Another ICTP Associate
Member (S. Mwandoto, from the Kenia Meteorological Department in Nairobi)
has visited ICTP from March to July 2000, working on regional verifications
of rainfall simulated by the PROVOST ensemble simulation. His visit
has provided a useful 'test-case' for the development of simple validation
and training tools for scientists from developing countries.
Specifically, a preprocessing
of rainfall data from ERA and the ECMWF PROVOST ensembles (as included
in the ECMWF CD-ROMs) has been performed, in order to allow an easy
comparison between rainfall anomalies from ERA
and the ensemble means
in different years/seasons. From this dataset, a GRADS script produces
colour plots of the two fields for specified periods (year, season,
range of 10-day means) and regions (five longitude bands can be selected).
It is planned to develop a web-based interface to simple verification
tools like this one, in collaboration with CINECA, (to be accessed from
the PROMISE archive web page), and to apply them to other experimental
datasets (e.g. PRISM).
Finally, a Summer Colloquium
on "Land-Atmosphere Interactions and the Hydrological Cycle",
including a training workshop and a research conference, has been planned
for 28 May - 15 June 2001. This event (with J. Slingo from UREADMY as
Co-Director) will address a number of PROMISE-related issues, and will
act as the main PROMISE meeting of 2001.