Core Project Details
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| Contract Number |
HPRN-CT-1999-00057 |
| Core Project Title |
ALADIN Training NETtwork |
| Acronym |
ALATNET |
| Start Date |
01/03/2000 |
| Finish Date |
29/02/2004 |
| Duration |
48 |
| Objectives |
ALATNET
(ALADIN Training NETwork) aims at diversifying and widening the
international research effort around the Numerical Weather Prediction
(NWP) Limited Area Model ALADIN. This software is currently used both
for daily short-range weather forecast (15 operational versions exist,
most of them running in dynamical adaptation mode) and for research
purposes.
The research effort was focused on the following topics:
non-hydrostatic modelling of the atmospheric flow, diabatic forcing at
small scales (when both "resolved" and "parameterized" computations mix
their effects), parameterisation of surface processes, coupling
strategies for high resolution applications and continuous data
assimilation, use of the optimal control formalism to assimilate
meteorological observations at the finest possible scales, development
of interfaces to new types of remote-sensed data, noise control in both
model runs and data assimilation procedures.
None of this topic,
taken individually, was likely to be the vector for a complete
breakthrough in atmospheric science. But all of them were required
steps for the basic objective : to built the ALADIN NWP system up to a
state where it can treat the dynamics and physics of atmospheric
phenomena at scales down to 10 km and where it can assimilate in a
continuous and balanced mode all relevant data for the prediction of
extreme weather events.
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| Partnerships |
Till
before ALATNET the basic training courses and the scientific progress
around ALADIN were centralized in Toulouse and widely supported by
Météo-France. However local training actions had developed along the
last years and a few decentralized research units emerged.
ALATNET
offered the opportunity to go further towards the decentralization of
scientific initiative and training effort, while facing the current
main scientific challenges of NWP.
The research efforts were
distributed among 5 leading centres (in Toulouse, Brussels, Prague,
Budapest and Ljubljana) and were opened to a closer cooperation with
other European NWP teams (UK, Italy) through a broader welcome of
students.
The coordination of scientific developments and training
actions received special care so that they would benefit equally to all
partners and preserve the main properties of the software (portability,
flexibility, generality, modularity), which ensure that every option
remains available to every NWP ALADIN partner team.
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| Applications |
(A) Links with operations:
Most
results of the work on physical parameterisations have already an
operational application in several ALADIN applications. Blending
assimilation is now operational in a few of them as well and full
3D-Var is in test at two places. But the most spectacular outcome is
perhaps the now planned application of the non-hydrostatic ALADIN
option in about twenty-five Euro-Mediterranean countries thanks to the
choice of the HIRLAM group to join forces with us on this issue.
(B) Publications (extended abstracts and papers):
(i)
Gospodinov, I., V. Spiridonov, P. Bénard and J.-F. Geleyn, 2002 : A
refined semi-Lagrangian vertical trajectory scheme applied to a
hydrostatic atmospheric model. Q. J. R. Meteorol. Soc.. (ii) Siroka,
M., G. Boloni, R. Brozkova, A. Dziedzic, C. Fischer, J.-F. Geleyn, A.
Horanyi, W. Sadiki and C. Soci, 2001 : Innovative developments for a
3D-Var analysis in a Limited Area Model: scale selection and blending
cycle. Research activities in atmospheric and oceanic modelling. (iii)
Soci, C., A. Horanyi and C. Fischer, 2003: High resolution sensitivity
studies using the adjoint of the ALADIN mesoscale numerical weather
prediction model. Idöjaras. (iv) Brozkova, R., D. Klaric, S.
Ivatek-Sahdan, J.-F. Geleyn, V. Cassé, M. Siroka, G. Radnoti, M.
Janousek, K. Stadlbacher and H. Seidl, 2001 : DFI blending: an
alternative tool for preparation of the initial conditions for LAM.
Research activities in atmospheric and oceanic modelling. (v) Siroka,
M., C. Fischer, V. Cassé, R. Brozkova and J.-F., Geleyn, 2002: The
definition of mesoscale selective forecast error covariances for a
limited area variational analysis. Meteorology and Atmospheric Physics.
(vi) Bénard, P., 2003: Stability of semi-implicit and iterative
centred-implicit time discretisations for various equation systems used
in NWP, Mon. Wea. Rev.. (vii) Bénard, P., 2004: On the use of a wider
class of linear systems for the design of constant coefficients
semi-implicit time-schemes in NWP. Mon. Wea. Rev.. (viii) Bénard, P.,
R. Laprise, J. Vivoda and P. Smolikova, 2004: Stability of leap-frog
constant-coefficient semi-implicit schemes for the fully elastic system
of Euler equations; flat-terrain case. Mon. Wea. Rev. (ix) Termonia,
P., 2003: Monitoring and improving the temporal interpolation of
lateral-boundary-coupling data for limited-area models. Mon. Wea. Rev..
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| Training Aspects |
ALATNET
offered pre-Doc and post-Doc positions in 5 teams : at Météo-France
(only pre-Doc), IRM (only post-Doc), CHMI, HMS (only pre-Doc) and HMIS
(only pre-Doc) respectively.
Research topics were distributed so
that each centre may specialize, but responsibilities in each of the
three historical research directions for NWP (dynamics and numerical
methods, physical parameterisations, data assimilation) were shared by
at least two teams. This enabled a larger choice for students, a wider
spreading of experience and a better control of the project completion.
The
French team is part of large research institute and benefited from
experience in NWP at the global scale, but the smaller teams allowed a
closer contact with operational weather prediction.
Theoretical
training courses, exploring the leading-edge topics of NWP
(high-resolution modelling, data assimilation, numerical methods) and
open to the whole European NWP community, were organized regularly and
completed the local, practical, training for newcomers.
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| Results |
After the four years of activity of ALATNET the following results have been registered.
(A) Research actions:
(i)
In the part concerning the non-hydrostatic formulation: (a) the
semi-implicit three-time-level semi-Lagrangian version of ALADIN has
been stabilised (it was thus the first or second version of this type
in the world to run with Courant numbers bigger than one) while the
search for a more and more optimal choice of prognostic variables led
to a mixed prognostic-diagnostic solution that gives a theoretical
explanation for the (up to now) empirically justified technique used in
the Canadian model MC2; (b) the iterative process that leads to the
two-time-level mirror version of the previously mentioned one has also
been stabilised, and has been optimised to even higher stability; (c)
the problem of the lower boundary condition in the semi-Lagrangian case
has been solved with two possible methods. (ii) For the ALADIN
variational tools the build of a solidly justified prototype of high
resolution 3D-Var is achieved with emphasis on (d) structure functions
computed with the so-called "lagged mode" (i.e. concentrating on the
scales that were not analysed by the model providing the lateral
boundary conditions) and (e) on the use of blending by digital filter
initialisation (a fully novel method for providing a spin-up-free
"first guess" at fine scale) to balance the high resolution data
assimilation in a way that preserves most of the innovation coming from
the observations. Still in this area, the work on specific features (f)
for the humidity and land surface analysis has lead to a 2D-Var
pioneering method with excellent results. (iii) For high resolution
physics the prognostic treatment of convective characteristics (g) is
achieved and emphasis has shifted on the one hand to the relaxation of
other 'larger scale' constraints for convection and on the other hand
to the other potential prognostic variables (turbulent kinetic energy
and condensates) while (h) the unexpected link between stable boundary
layer fluxes and cyclogenesis much downstream in the flux has been
confirmed with an improved and smoother parameterisation of the
turbulent fluxes in such cases. (iv) On a more case-to-case basis
important progress was also achieved in the following areas: (i) snow
evolution modelling and snow analysis, (j) understanding the respective
roles of orography, time-stepping, non-hydrostatism and horizontal
resolution in the control of numerical noise, (k) comprehension of the
reasons why the previous attempt to build a radiative upper boundary
condition failed, (l) role of the "regularised physics" in TL/AD
processes at high resolution, (m) a new formulation of the drag and
lift effects of the sub-grid scale orography, (n) a completely new way
to look at the problem of information monitoring between coupling and
coupled models, (o) an alternative to the constant coefficient lateral
diffusion schemes in spectral models and (p) a new way to analyse
sources of latent non-linear instability and stiffness in diabatic
models.
(B) Teaching actions:
(i) practical training organized regularly for newcomers locally in each ALATNET centre.
(ii) ALATNET Seminar on High Resolution Modelling, Radostovice (CZ),15-26 May, 2000.
(iii) ALATNET Seminar on Data Assimilation, Gourdon (F), 11-22 June, 2001.
(iv) ALATNET Seminar on Numerical Methods, Kranjska Gora (Si), 27-31 May 2002.
(v) ALATNET Concluding seminar, Kiralyret (Hu), 15-17 October 2003.
(C) Fulfilled Young Researchers contracts:
(i) Post-Doc in Brussels: Martin GERA (Sk) and Ilian GOSPODINOV (Bg).
(ii)
Pre-Doc in Toulouse: Gianpaolo BALSAMO (It, PhD already defended),
Margarida BELO-PEREIRA (Pt), Andre SIMON (Sk), Cornel SOCI (Ro, PhD
already defended) and Malgorzata SZCZECH (Po).
(iii) Pre-Doc in Budapest: Steluta ALEXANDRU (Ro).
(iv) Pre-Doc in Ljubljana: Raluca RADU (Ro) and Klaus STADLBACHER (Au).
(vi) Pre-Doc in Prague: Jozef VIVODA (Sk). Pos-Doc in Prague: Christopher SMITH (UK).
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| Web Site |
http://www.cnrm.meteo.fr/alatnet/
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| Fellowship Type |
Research Training Networks FP5 |
| Last Update |
29/04/2004 |
| Partners |
| Partner Name |
Institution and Department Name |
Town Name |
Country |
| Prof. Alfred QUINET |
Institut Royal Météorologique |
BRUSSELS |
Belgium |
| Dr. Radmila BROZKOVA |
Cesky HydroMeteorologicky Ustav |
PRAHA |
Czech Republic |
| Dr. Andras HORANYI |
Hungarian Meteorological Service |
BUDAPEST |
Hungary |
| M. Jure JERMAN |
Ministry of Environment and Physical Planning, HydroMeteorological Institute of Republic of Slovenia |
LJUBLJANA |
Slovenia |
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| Coordinator |
Jean-François GELEYN
CNRM/GMAP
Meteo-France
42 Avenue G. Coriolis
31057 TOULOUSE CEDEX 1
France
Phone: +33(0)5.61.07.84.50
FAX: +33(0)5.61.07.84.53
jean-francois.geleyn@meteo.fr
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