Multiscale performance of the ALARO-0 model forsimulating extreme summer precipitation climatology in
Belgium
Rozemien De Troch1,2, Rafiq Hamdi1, Hans Van de Vyver1,Jean-Francois Geleyn2,3, Piet Termonia1,2
1Royal Meteorological Institute of Belgium; 2Department of Physics and Astronomy, GhentUniversity, Ghent, Belgium; 3Czech Hydrometeorological Institute, Prague, Czech Republic
COST Action WG1+2 Meeting on Parameterization and DownscalingJanuary 29-30, 2014, Milan
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 1 / 13
1 Introduction
2 Experimental Design
3 Results
4 Conclusion
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 2 / 13
Models
ARPEGE-IFSGLOBAL
ALADINLIMITED AREA MODEL (LAM)
+New physics
parameterizations centered around
improved convection and cloud scheme
ALARO-0MESOSCALE AND
CONVECTIVE SCALE = “GREY-ZONE” SCALES
= 3MT
(Gerard and Geleyn, 2005; Gerard et al., 2009)
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 3 / 13
Context8 km 4 km Radar (obs.)
2 km 1 km 1 km (no 3MT)
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 4 / 13
Goal
Explore the relative importance of resolution versusparameterization formulation on the model skill to simulate
realistic extreme daily precipitation
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 5 / 13
Experimental Design
ERA-40 reanalysis1961-1990
ALARO-0 40 km1961-1990
ALADIN 40 km1961-1990
ALARO-0 10 km1961-1990
ALARO-0 4 km1961-1990
ALADIN 10 km1961-1990
DYNAMICALDOWNSCALING
ONE-WAY NESTING
DRIVING LAM
HIGH RESOLUTION
LAM
GLOBAL REANALYSIS
ALADIN-ClimateCNRM 25 km1961-1990
ENSEMBLES
Station Observations1961-1990
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 6 / 13
Experimental Design
ALARO-0 10 km1961-1990
ALARO-0 4 km1961-1990
ALADIN 10 km1961-1990
ONE-WAY NESTING
HIGH RESOLUTION
LAM
GLOBAL REANALYSIS
ALADIN-ClimateCNRM 25 km1961-1990
ENSEMBLES
Station Observations1961-1990
DRIVING LAM
ERA-40 reanalysis1961-1990
ALARO-0 40 km1961-1990
ALADIN 40 km1961-1990
DYNAMICALDOWNSCALING
(i) What is the effect of dynamical downscaling ERA-40 using ALARO-0?
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 6 / 13
Experimental Design
DRIVING LAM
ERA-40 reanalysis1961-1990
DYNAMICALDOWNSCALING
ALARO-0 40 km1961-1990
ALADIN 40 km1961-1990
ALARO-0 10 km1961-1990
ALARO-0 4 km1961-1990
ALADIN 10 km1961-1990
ONE-WAY NESTING
HIGH RESOLUTION
LAM
GLOBAL REANALYSIS
ALADIN-ClimateCNRM 25 km1961-1990
ENSEMBLES
Station Observations1961-1990
(ii) Does ALARO-0 give an improvement to ALADIN at varying horizontal resolutions?
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 6 / 13
Experimental Design
ERA-40 reanalysis1961-1990
ALARO-0 40 km1961-1990
ALADIN 40 km1961-1990
ALARO-0 10 km1961-1990
ALARO-0 4 km1961-1990
ALADIN 10 km1961-1990
DYNAMICALDOWNSCALING
ONE-WAY NESTING
HIGH RESOLUTION
LAM
GLOBAL REANALYSIS
ALADIN-ClimateCNRM 25 km1961-1990
ENSEMBLES
Station Observations1961-1990
DRIVING LAM
(iii) How does ALARO-0 perform within the context of state-of-the-art regional climate
modelling?
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 6 / 13
Observations
0
50
100
150
200
250
300
350
400
450
500
550
600
650m
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 7 / 13
(i) Effect of downscaling ERA-40
0 10 20 30 40 50 60 70 80 90 100 110
1e−06
1e−04
1e−02
1e+00
1e+02 OBSq0.95 OBSERA40 PSS: 0.76 PSS<q0.95: 0.89 PSS>q0.95: 0.62ALARO−0 (40km) PSS: 0.85 PSS<q0.95: 0.95 PSS>q0.95: 0.75ALADIN (40km) PSS: 0.80 PSS<q0.95: 0.86 PSS>q0.95: 0.75
Precipitation (mm/day)
Relat
ive fre
quen
cy (lo
g)
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 8 / 13
(ii+iii) Improvement of ALARO-0
40 km
10 km
4 km
ALARO-0
OBS
ALADIN
CNRM
25 km
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 9 / 13
(ii+iii) Improvement of ALARO-0
1e−06
1e−04
1e−02
1e+00
1e+02
0 30 60 90 120 160
OBS
q0.95 OBS
ALARO−0 (40km)
PSS: 0.85
PSS<q0.95: 0.95
PSS>q0.95: 0.75
0 30 60 90 120 160
OBS
q0.95 OBS
ALADIN (40km)
PSS: 0.80
PSS<q0.95: 0.86
PSS>q0.95: 0.75
0 30 60 90 120 160
OBS
q0.95 OBS
CNRM (25km)
PSS: 0.76
PSS<q0.95: 0.81
PSS>q0.95: 0.70
1e−06
1e−04
1e−02
1e+00
1e+02
0 30 60 90 120 160
Relat
ive fr
eque
ncy (
log)
Precipitation (mm/day)
X ALARO-0 (40km)● ALARO-0 (10km)♦ ALARO-0 (4km)* ALADIN (40km)▲ ALADIN (10km)■ CNRM (25km)
OBS
q0.95 OBS
ALARO−0 (10km)
PSS: 0.86
PSS<q0.95: 0.95
PSS>q0.95: 0.76
0 30 60 90 120 160
OBS
q0.95 OBS
ALADIN (10km)
PSS: 0.79
PSS<q0.95: 0.84
PSS>q0.95: 0.74
1e−06
1e−04
1e−02
1e+00
1e+02
0 30 60 90 120 160
OBS
q0.95 OBS
ALARO−0 (4km)
PSS: 0.85
PSS<q0.95: 0.95
PSS>q0.95: 0.75
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 10 / 13
Conclusions
1 What is the effect of dynamical downscaling ERA-40 usingALARO-0?⇒ Dynamical downscaling of ERA-40 using ALARO-0 adds value to
the simulation of extreme daily summer precipitation whencompared to ERA-40.
2 Does ALARO-0 give an improvement to ALADIN at varyinghorizontal resolutions?⇒ Frequencies and statistics from Extreme value analysis −→ The
new parameterization scheme of ALARO-0 contributes to theimprovement in the modelling of extreme precipitation events atvarying horizontal resolutions, rather than the increase in spatialresolution.
3 How does ALARO-0 perform within the context ofstate-of-the-art regional climate modelling?⇒ ALARO-0 is a good candidate model for regional climate modelling.
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 11 / 13
Conclusions
1 What is the effect of dynamical downscaling ERA-40 usingALARO-0?⇒ Dynamical downscaling of ERA-40 using ALARO-0 adds value to
the simulation of extreme daily summer precipitation whencompared to ERA-40.
2 Does ALARO-0 give an improvement to ALADIN at varyinghorizontal resolutions?⇒ Frequencies and statistics from Extreme value analysis −→ The
new parameterization scheme of ALARO-0 contributes to theimprovement in the modelling of extreme precipitation events atvarying horizontal resolutions, rather than the increase in spatialresolution.
3 How does ALARO-0 perform within the context ofstate-of-the-art regional climate modelling?⇒ ALARO-0 is a good candidate model for regional climate modelling.
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 11 / 13
Conclusions
1 What is the effect of dynamical downscaling ERA-40 usingALARO-0?⇒ Dynamical downscaling of ERA-40 using ALARO-0 adds value to
the simulation of extreme daily summer precipitation whencompared to ERA-40.
2 Does ALARO-0 give an improvement to ALADIN at varyinghorizontal resolutions?⇒ Frequencies and statistics from Extreme value analysis −→ The
new parameterization scheme of ALARO-0 contributes to theimprovement in the modelling of extreme precipitation events atvarying horizontal resolutions, rather than the increase in spatialresolution.
3 How does ALARO-0 perform within the context ofstate-of-the-art regional climate modelling?⇒ ALARO-0 is a good candidate model for regional climate modelling.
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 11 / 13
Thank you for your attention!Questions?
De Troch, R., Hamdi, R., Van de Vyver, H., Geleyn, J.-F. andTermonia, P. (2013).Multiscale Performance of the ALARO-0 Model for SimulatingExtreme Summer Precipitation Climatology in Belgium.Journal of Climate 26, 8895–8915 .
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 12 / 13
References
Gerard, L. and Geleyn, J.-F. (2005).Evolution of a subgrid deep convection parameterization in alimited area model with increasing resolution.Quart. J. Roy. Meteor. Soc. 131, 2293–2312.
Gerard, L., Piriou, J.-M., Brozkova, R., Geleyn, J.-F. and Banciu, D.(2009).Cloud and Precipitation Parameterization in a Meso-Gamma-ScaleOperational Weather Prediction Model.Monthly Weather Review 137, 3960–3977.
Hamdi, R., Van de Vyver, H. and Termonia, P. (2012).New cloud and microphysics parameterisation for use inhigh-resolution dynamical downscaling: application for summerextreme temperature over Belgium.Int. J. Climatol. 32, 2051–2065.
R. De Troch (RMIB) Multiscale performance of ALARO-0 COST WG1+2 2014 13 / 13
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