Regional climate modelling in Belgium with the Regional Climate Model MAR

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Regional climate modelling in Belgiumwith the
Regional Climate Model MAR
Université catholique de Louvain
(Louvain-la-Neuve, Belgium) Institute of
astronomy and geophysics Georges Lemaître

• Emilie Vanvyve 1st year PhD student
• Pr. J.-P. van Ypersele (adviser, UCL-ASTR,
  Belgium)
• Dr H. Gallée (co-adviser, LGGE, France)

26 May 6 June 2003 Workshop on the Theory and
Use of Regional Climate Models
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Contents

• Motivations ... Future climate in Belgium ?
• Thesis subject plan
• The MAR model
• Current simulations December 1993, a very wet
  month
• Some results
• Conclusion next steps

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1. Climate change ... Future climate in Belgium ?

• MORE intense precipitation events (IPCC, WGI)
• 1950-2000 observed changes likely (66-90),
  over many Northern Hemisphere mid- to high
  latitude land areas
• 2000-2100 projected changes very likely
  (90-99), over most areas

• Thesis subject
• Study of the global warming impacts on the
  extreme precipitation regime over Belgium for the
  21st century
• with a RCM Modèle Atmosphérique Régional

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1. Climate change ... Future climate in Belgium ?

• Validation of MAR for simulating intense
  precipitation events in present climate
• Winter 1993, winter 1995, summer 2002
• Climate change study
• Reference simulation 10 years in actual climate
• Climate change simulation middle 21st century

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2. The MAR model (Gallée Schayes, 1994)

• Some features
• Limited-area model (grid-point, primitive
  equations)
• Hydrostatic (non-hydrostatic in development)
• ? levels, cartesian horizontal coordinates (1 to
  50 km-resolution), 0 to 3D
• Initial and boundary conditions ECMWF, GCM
  output, MAR output, observations,
• Surface submodel Deardorff (1978), SISVAT
  (Soil/Ice Snow Vegetation Atmosphere Transfer
  scheme)
• Used in France (LGGE, LTHE, LMD), Belgium
  (ASTR-UCL), Benin, Ivory Coast
• Over
• Polar regions (Antarctica, Greenland) mass
  balance
• Africa (Western Africa) hydrology, synoptic,
  stochastic disaggregation, interannual
  variability, convection
• Europe physical disaggregation in the Alpes,
  intense (precipitation) events, GCM coupling

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3. Current simulations December 1993, a very
wet month

• MAR setup

Period December 1993
Domain 4320x4320 km
Resolution 40 km
Time step 120 s
Initialisation re-analysis (ECMWF)
Boundary forcing re-analysis (ECMWF), every 6 hours
Other Deardorff (surface submodel) Fritsch-Chappell (convective adjustment)
MAR domain (108x108x40)
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3. Current simulations December 1993, a very
wet month

• Sea-level pressure (daily mean) in  Belgium 

• Temperature at 750 hPa (daily mean) in  Belgium 

Royal Meteorological Institute (Brussels)
observations Whole month characterized by
successive low pressure systems from the 7th
December, leading to an extreme rainy weather and
serious floods in the southern Belgium.
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3. Current simulations December 1993, a very
wet month

• Effect of domain size on the monthly
  precipitation amount

largest
smallest
medium
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3. Current simulations December 1993, a very
wet month

• Effect of domain size on the monthly
  precipitation amount in  Belgium 

medium domain
largest domain
smallest domain
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3. Current simulations December 1993, a very
wet month

• Monthly precipitation amount (largest domain)

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3. Current simulations December 1993, a very
wet month

• Daily/monthly precipitation in Belgium

RMI observations maxima between 20 and 70
mm/day observed on the 12th, 19th, 20th and 30th
MAR simulated precipitation 65 of observed
precipitations
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Conclusion next steps

• Daily values of temperature, pressure agree with
  observations
• Daily and spatial distribution of precipitation
  agrees with observations
• But precipitation amount is underestimated by
  35. Possible error sources
• Coarse definition of sub-domain  Belgium 
• MAR resolution too low
• ECMWF fields enough water ?
• Model physics well parameterized/adapted to the
  situation ?
• ? December 1993 meteorological situation over
  Belgium is well simulated by MAR.
• Go on with the validation of winter 1993,

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2. The MAR model

• Limited-area model (grid-point, primitive
  equations)Gallée Schayes, 1994, UCL-ASTR

• DYNAMICS
• Hydrostatic (non-hydrostatic in development)
• Grid
• s normalized pression (upto 60 levels)
• Cartesian horizontal coordinates1 to 50
  km-resolution
• 0D (ground) to 3D
• Initial and boundary conditions
• ECMWF re-analysis, GCM (LMDz),
• observations (necessary pre-processing)
• MAR output

• PHYSICS
• Radiative transfers Solar (Fouquart Bonnel,
  1980), Infrared (Morcrette, 1984)
• Turbulence closures 1.5 order (Therry
  Lacarrère, 1982), K-e (Duynkerke, 1980)
• Convective adjustement Bechtold (2000), Fritsch
  Chappell (1980) Brasseur (1999), Kain
  Fritsch (1990)
• Microphysics (Kessler, 1969)
• Surface layer fluxes (Businger, 1973)
• Surface submodel Deardorff (1978), SISVAT
  (Soil/Ice Snow Vegetation Atmosphere Transfer
  Scheme)
• SST (ERA-15, Reynolds SST, )

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2. The MAR model

• LGGE (France) H. Gallée
• Polar regions (Antarctica) mass balance
• ASTR (Belgium) J.-P. van Ypersele (? Yvory
  Coast)
• Polar regions (Greenland) mass balance
• Europe intense precipitation events
• LTHE (France) (? Benin)
• Africa (Western Africa) hydrology, synoptic,
  stochastic disaggregation, interannual
  variability, convection
• Europe (Alpes) physical disaggregation
• LMD (France)
• Europe GCM coupling

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Southern part of the domain cold bias

• Cold bias linked to a pressure positive bias

TMAR (600 hPa) TECMWF (600 hPa)
Sea-level PMAR Seal-level PECMWF
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Climate change in Belgium ?

• MORE intense precipitation events (IPCC, WGI)

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the MAR team
MAR