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Regional climate modelling in Belgium with the Regional Climate Model MAR

Université catholique de Louvain (Louvain-la-Neuve, Belgium) Institute of astronomy and geophysics Georges Lemaître. Regional climate modelling in Belgium with the Regional Climate Model MAR. Emilie Vanvyve – 1st year PhD student Pr. J.-P. van Ypersele (adviser, UCL-ASTR, Belgium)

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Regional climate modelling in Belgium with the Regional Climate Model MAR

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

  2. 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

  3. Floods in Belgium • in winter (long rainfall) : too much rain on a too long time • in summer (storms) : too much rain on a too short time 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

  4. Phys. disaggregator of precip.Hydrological modelHydro-meteo coupling Re-analyses (ECMWF)MAR outputGCM (LMDz) MAR 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

  5. 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

  6. « Belgium » 3. Current simulations : December 1993, a very wet month … • MAR setup MAR domain (108x108x40)

  7.       MARRE-ANALYSIS 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.

  8. 3. Current simulations : December 1993, a very wet month … • Effect of domain size on the monthly precipitation amount largest smallest medium

  9. 3. Current simulations : December 1993, a very wet month … • Effect of domain size on the monthly precipitation amount in « Belgium » largest domain medium domain smallest domain

  10. « Belgium » MAR Snowfall Total Convective Non-convective GPCC 3. Current simulations : December 1993, a very wet month … • Monthly precipitation amount (largest domain)

  11.    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

  12. 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, …

  13. 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, …)

  14. 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

  15. 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

  16. Confidence in observed changes(1950-2000) :likely (66-90%), over many Northern Hemisphere mid- to high latitude land areas Confidence in projected changes(2000-2100) :very likely (90-99%), over most areas Belgium (IS92a scenario) Winter 2070-99 2040-69 2010-39 Precipitation and temperature changes versus reference period 1969-1990 Climate change in Belgium ? • MORE intense precipitation events (IPCC, WGI)

  17. LMD(Paris, France) EUROPE with P. Marbaix (BIOCLIM) Benin GCM coupling continental water Continental ice LTHE(Grenoble, France) AFRICA (Sahel) LGGE(Grenoble, France) POLAR (Antarctic) with H. GALLEE (conception, mass balance) (VIDAS, ATHENA, RIME) Africa – hydrology Polar Hydrological coupling SynopticStochastic disaggregation Interannual variability Convection EUROPE (Alpes) Physical disaggregation ASTR(UCL, Belgium) J.-P. VAN YPERSELE POLAR (Greenland) with X. Fettweis (mass balance) EUROPE (& Belgium) with E. Vanvyve (climate change, intense precipitation events) Ivory Coast the MAR team MAR

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