NOCN03 CWAO 241910 GENOT TLTP. NO.001 ON TUESDAY OCTOBER 31TH 2006, AT 12 UTC, THE CANADIAN METEOROLOGICAL CENTRE WILL IMPLEMENT MAJOR CHANGES TO THE OPERATIONAL GLOBAL FORECAST SYSTEM INCREASING SIGNIFICANTLY THE RESOLUTION OF THE GLOBAL ENVIRONMENTAL MULTISCALE (GEM) MODEL AND IMPROVING ITS PHYSICAL PARAMETERIZATION. SUMMARY OF THE CHANGES TO THE GLOBAL CONFIGURATION OF THE GEM MODEL DYNAMICAL CONFIGURATION THE FORECAST MODEL HORIZONTAL RESOLUTION WILL SIGNIFICANTLY INCREASE FROM ABOUT 100 KM (400 X 200 GRID POINTS) TO NEARLY 33 KM AT MID LATITUDES (800 X 600 GRID POINTS). THE NUMBER OF VERTICAL LEVELS WILL INCREASE FROM 28 TO 58, THE TOP OF THE MODEL REMAINING AT 10 HPA. THE TIME STEP WILL CONSEQUENTLY BE REDUCED FROM 2700 TO 900 SECONDS. THE SPONGE LAYER NEAR THE MODEL LID WILL INCLUDE 4 LEVELS INSTEAD OF 1. IN THIS LAYER, THE HORIZONTAL DIFFUSION IS INCREASED IN ORDER TO MINIMIZE THE NEGATIVE IMPACT OF SPURIOUS WAVES REFLECTED AT THE LID. PHYSICAL PARAMETERIZATIONS THE PHYSICAL CONFIGURATION OF THE FORECAST MODEL WILL BE SUBSTANTIALLY MODIFIED COMPARED TO THE OLD OPERATIONAL VERSION. THE CONDENSATION AND PRECIPITATION PACKAGE, IN PARTICULAR, WAS CHANGED QUITE DRASTICALLY. THE KAIN-FRITSCH SCHEME WILL REPLACE THE KUO SCHEME FOR THE DEEP CONVECTION. THIS ALLOWS FOR A LARGER CONTRIBUTION OF THE GRID-SCALE (RESOLVED) CONDENSATION PROCESSES WHICH IS CONSISTENT WITH THE INCREASE IN RESOLUTION. THE SUNDQUIST GRID-SCALE CONDENSATION SCHEME WAS MODIFIED MOSTLY WITH RESPECT TO THE PRECIPITATION EVAPORATION BELOW CLOUD BASE, WHICH IS DONE OVER SEVERAL LEVELS IN THE NEW VERSION. ANOTHER CHANGE TO THE CONDENSATION SUITE IS THE INCLUSION OF A SHALLOW CONVECTION SCHEME, BASED ON A KUO SCHEME CLOSURE, CALLED KUO TRANSIENT. THE SURFACE MODELING SCHEME KNOWN AS ISBA (INTERACTIONS, SURFACE, BIOSPHERE, AND ATMOSPHERE) WILL REPLACE THE SO-CALLED 'FORCE-RESTORE' MODULE. ISBA IS MORE SOPHISTICATED IN ITS TREATMENT OF SOIL, VEGETATION, AND SNOW. TOGETHER WITH ISBA, A LAND-SURFACE 6-HOURS DATA ASSIMILATION SYSTEM WILL BE IMPLEMENTED IN ORDER TO PROVIDE INITIAL CONDITIONS OF SURFACE TEMPERATURES AND MOISTURE. THE INCREASE IN RESOLUTION OF THE MODEL AND THE USE OF ISBA MAKES THE SNOW ANALYSIS MORE PRECISE. ANOTHER MODEL PHYSICS MODIFICATION IS THE USE OF THE BOUGEAULT AND LACARRERE MIXING LENGTH FOR VERTICAL DIFFUSION DUE TO ATMOSPHERIC TURBULENCE, PROVIDING A CLEAR IMPROVEMENT OVER THE ONE PREVIOUSLY USED, ESPECIALLY FOR CONVECTIVE, WELL-MIXED, BOUNDARY LAYERS. SUMMARY OF THE CHANGES TO THE GLOBAL DATA ASSIMILATION SYSTEM A NEW SET OF BACKGROUND ERROR STATISTICS ON THE 58 MODEL LEVELS HAS BEEN COMPUTED USING THE SO-CALLED NMC METHOD. AS IN THE PREVIOUS IMPLEMENTATION OF 4D-VAR, A LOW-RESOLUTION MODEL IS USED TO PROPAGATE THE ANALYSIS INCREMENTS (T108) OVER THE 6 HOURS DATA ASSIMILATION WINDOW. THE SET OF PHYSICAL PARAMETERIZATIONS FOR THIS MODEL HAS BEEN CHANGED TO THOSE NOW USED IN THE NEW FORECAST MODEL DESCRIBED ABOVE. HOWEVER, THE CORRESPONDING SIMPLIFIED PHYSICAL PARAMETERIZATIONS USED IN THE TANGENT LINEAR MODEL AND ITS ADJOINT MODEL REMAIN THE SAME AS BEFORE. THE COMPUTATIONAL EFFICIENCY OF THE 4D-VAR DATA ASSIMILATION SYSTEM HAS BEEN IMPROVED BY 40 OVERALL. THE CUT-OFF TIMES FOR AVAILABILITY OF OBSERVATIONS HAVE BEEN SLIGHTLY MODIFIED TO DELIVER THE OPERATIONAL ANALYSES AT ABOUT THE SAME TIME AS IN THE PREVIOUS GLOBAL FORECAST SYSTEM. IMPACTS ON PRODUCTS AND POST-PROCESSING ALL PRODUCTS BASED ON OUTPUTS OF THE NEW GLOBAL MODEL HAVE BEEN GENERATED AND VALIDATED DURING THE PARALLEL RUN. SOME CHANGES WERE DONE TO THE AVIATION WEATHER PACKAGE. THE THRESHOLD VALUES USED TO ASSESS MODERATE AND SEVERE TURBULENCE WERE ADJUSTED TO BE CONSISTENT WITH THOSE USED ON THE REGIONAL MODEL. AESTHETIC MODIFICATIONS HAVE ALSO BEEN DONE ON THE CONTOURING OF THE FREEZING LEVEL AND TROPOPAUSE HEIGHT CHART. IN THE CLASSICAL 4-PANEL CHARTS, THE MEAN SEA LEVEL PRESSURE IS NOW FILTERED. THE FILTERING OF VORTICITY AND VERTICAL MOTION HAS BEEN INCREASED. THE 10 AND 30 PERCENT CONTOURS OF RELATIVE HUMIDITY HAVE BEEN ELIMINATED. ALL OTHER PRODUCTS WERE VALIDATED WITHOUT PROBLEMS. THE UMOS SYSTEM HAS BEEN RUNNING IN THE NEW GLOBAL MODEL PARALLEL RUN SINCE THE VERY BEGINNING. THIS ALLOWED UMOS TO BEGIN ITS ADAPTATION PERIOD EARLY IN THE MODEL TRANSITION PROCESS. VERIFICATIONS OF THE UMOS TEMPERATURES BASED ON OUTPUTS OF THE NEW GLOBAL MODEL SHOW THAT THE BIASES ARE VERY SIMILAR IN AMPLITUDE TO WHAT IS OBSERVED IN THE UMOS TEMPERATURES BASED ON THE OLD GLOBAL MODEL, BUT SHOW A MORE REALISTIC DIURNAL CYCLE. HOWEVER, THE ROOT MEAN SQUARE ERROR OF THE UMOS TEMPERATURES BASED ON THE NEW GLOBAL MODEL IS ABOUT ONE DEGREE CELSIUS LOWER AT ALL PROJECTION TIMES THAN DIRECT MODEL OUTPUT. THE SCRIBE FORECASTS GENERATED IN AUTOMATED MODE FROM THE OUTPUTS OF THE NEW GLOBAL MODEL WERE VERIFIED. IT IS NOTED THAT THE SCRIBE FORECASTS ARE IMPROVED FOR ALL WEATHER ELEMENTS AND AT ALL PROJECTION TIME FROM DAY ONE TO DAY FIVE INCLUSIVE, EXCEPT PERHAPS FOR THE WIND SPEED. SCRIBE HAS A TENDENCY TO FORECAST SOMEWHAT STRONGER WIND SPEEDS BASED ON THE NEW GLOBAL MODEL COMPARED TO THE OLD MODEL AND TO UNDERESTIMATE SOMEWHAT THE FREQUENCY OF LIGHT WINDS. THIS DECREASES SOMEWHAT THE PERCENTAGE OF THE WIND SPEED FORECASTS THAT ARE CORRECT CALCULATED FROM CONTINGENCY TABLES. HOWEVER, THE WIND DIRECTION IS SIGNIFICANTLY IMPROVED. PROFILES AT SPECIFIC POINTS OF THE MODEL OUTPUT SENT TO THE REGIONAL OFFICES IN BUFR FORMAT WILL CONTAIN THE FULL VERTICAL RESOLUTION (58 LEVELS) OF THE NEW MODEL. HOWEVER, THE GRIDDED DATA IN GRIB FORMAT WILL NOT CHANGE IN RESOLUTION FOLLOWING THE IMPLEMENTATION. OF COURSE EVEN AT THEIR CURRENT RESOLUTION, THE GRIB PRODUCTS WILL BENEFIT FROM THE METEOROLOGICAL GAINS OF THE NEW MODEL. THE FEASIBILITY OF INCREASING THE GRIB DATASET RESOLUTION TO 33 KM WILL BE EVALUATED AGAINST USER REQUIREMENTS AND AVAILABLE BANDWIDTH RESOURCES BEFORE A DECISION IS MADE. USERS WILL SEE CHANGES IN THE RECEPTION TIME OF THE GLOBAL OPERATIONAL PRODUCTS WITH THIS IMPLEMENTATION. PRODUCTS FROM THE GLOBAL SUITE WILL BE RECEIVED ABOUT 40 TO 55 MINUTES LATER WITH RESPECT TO THE CURRENT RECEPTION TIME. SPECIFICALLY THE GLOBAL SCRIBE MATRICES WILL BE DELIVERED 55 MINUTES LATER. WE WILL BE IN A POSITION TO CORRECT THIS SITUATION WITH AN INCREASE IN COMPUTING POWER SCHEDULE FOR THE FIRST MONTHS OF 2007. SUMMARY OF THE OBJECTIVE AND SUBJECTIVE EVALUATIONS EXTENSIVE PRELIMINARY TESTING IN BOTH SUMMER AND WINTER CONDITIONS WAS NECESSARY TO ACHIEVE THE FINAL CONFIGURATION. THE MODEL AND THE UPGRADED DATA ASSIMILATION SYSTEM RAN IN PARALLEL FOR 5 MONTHS, DURING WHICH TIME IT WAS COMPARED AND EVALUATED BOTH OBJECTIVELY AND SUBJECTIVELY. OVER THE COURSE OF THE PARALLEL RUN PERIOD, THE MESO-GLOBAL MODEL GENERALLY OUTPERFORMED THE OPERATIONAL MODEL QUITE SIGNIFICANTLY AS MEASURED AGAINST THE GLOBAL RADIOSONDE OBSERVATION NETWORK. OVER NORTH AMERICA, ROOT MEAN SQUARE ERRORS OF THE MASS FIELDS WERE REDUCED SIGNIFICANTLY, ESPECIALLY FOR GEOPOTENTIAL HEIGHT AND TEMPERATURES IN THE 1-5 DAY PERIOD. THE SIGNAL FOR THE WIND FORECASTS WAS POSITIVE AT JET LEVEL, BUT NEUTRAL IN THE MID LEVELS OF THE ATMOSPHERE AND SLIGHTLY POORER IN THE LOW LEVELS. THE STRONGEST IMPROVEMENTS ARE NOTED OVER THE TROPICS, WHILE THE MESO-GLOBAL ALSO PERFORMED WELL OVER THE SOUTHERN HEMISPHERE AND OVER ASIA. FOR THE PRECIPITATION FORECASTS, THE MESO-GLOBAL SCORES AGAINST BOTH THE NORTH AMERICAN SYNOPTIC NETWORK OBSERVATIONS AND THE HIGH-RESOLUTION U.S. SHEF NETWORK WERE MUCH IMPROVED IN THE 0-0.2 MM CLASS, INDICATIVE OF STRONGER DISCRIMINATION BETWEEN PRECIPITATION AND NO PRECIPITATION CASES. MEANWHILE THE MODEL ALSO PERFORMED MUCH BETTER IN THE HIGHER AMOUNTS (25 MM). MODEL BIASES WERE STRONGLY IMPROVED FOR ALL PRECIPITATION CLASSES. OVERALL THE SCORES INDICATE MUCH IMPROVED UTILITY OF THE MESO-GLOBAL MODEL PRECIPITATION FORECASTS. THE NEW SYSTEM WAS SUBJECTIVELY EVALUATED IN COMPARISON WITH THE OLD SYSTEM. DURING THE PARALLEL RUN, EVALUATION IN OPERATIONS OF THE NEW SYSTEM WAS GENERALLY PREFERRED TO THE OLD GLOBAL FORECAST SYSTEM FOR BOTH THE MASS FIELDS AND THE QUANTITATIVE PRECIPITATION FORECAST (QPF). THE NEW MODEL WAS MORE ACTIVE AND DEVELOPED STRONGER SYSTEMS WHICH WERE GENERALLY MORE REALISTIC INCLUDING FOR TROPICAL SYSTEMS. HURRICANE TRACKS AND TRANSITION TO EXTRATROPICAL STORMS WERE BETTER HANDLED. PRECIPITATION AMOUNTS AND PATTERNS WERE NOTED TO BE MUCH IMPROVED WITH THE NEW FORECAST SYSTEM. IMPACT ON REGIONAL MODEL: SINCE THE REGIONAL MODEL FEEDS FROM THE GLOBAL ASSIMILATION CYCLE OBJECTIVE ANALYSIS EVERY 12 HOURS, THE IMPLEMENTATION OF A NEW GLOBAL HAS AN IMPACT ON THE REGIONAL CYCLE ITSELF. THE MASS FIELD SCORES FOR THE GEM REGIONAL MODEL SPUN UP FROM THE MESO-GLOBAL WERE GENERALLY NEUTRAL IN COMPARISON WITH THE OPERATIONAL MODEL FOR DAY 1 AND SLIGHTLY, BUT CONSISTENTLY, IMPROVED FOR DAY 2. PRECIPITATION SCORES WERE GENERALLY NEUTRAL. THE SUBJECTIVE VERIFICATION HAS SHOWN SMALL BENEFITS IN THE FORECASTS OF THE MASS FIELDS BUT ALSO IN THE PRECIPITATION VERIFICATION. ADDITIONAL DETAILS ABOUT THIS IMPLEMENTATION WILL BE AVAILABLE ON OCTOBER 30TH 2006 AT THE FOLLOWING URL: HTTP://WWW.SMC.EC.GC.CA/CMC/OP_SYSTEMS/RECENT_E.HTML FOR QUESTIONS ABOUT THIS IMPLEMENTATION, YOU CAN WRITE AT: PRODUCTION-INFO(AT)CMC.EC.GC.CA MARDI LE 31 OCTOBRE 2006, A 12 UTC, LE CENTRE METEOROLOGIQUE CANADIEN IMPLANTERA UN NOUVEAU SYSTEME GLOBAL DE PREVISION AUX OPERATIONS. LES CHANGEMENTS SONT MAJEURS AUTANT DANS LA RESOLUTION DU MODELE GEM (GLOBAL ENVIRONNEMENTAL MULTI-ECHELLE) QUE DANS LA PARAMETRISATION PHYSIQUE UTILISEE. RESUME DES CHANGEMENTS A LA CONFIGURATION GLOBALE DU MODELE GEM CONFIGURATION DYNAMIQUE LA RESOLUTION HORIZONTALE DU MODELE DE PREVISION AUGMENTERA DE FACON SIGNIFICATIVE. ELLE PASSERA D'ENVIRON 100 KM (400 X 200 POINTS DE GRILLE) A PRES DE 33 KM AUX LATITUDES MOYENNES (800 X 600 POINTS DE GRILLE). LE NOMBRE DE NIVEAUX DANS LA VERTICALE AUGMENTERA DE 28 A 58, LE TOIT DU MODELE DEMEURANT A 10 HPA. LE PAS DE TEMPS SERA REDUIT EN CONSEQUENCE, PASSANT DE 2700 A 900 SECONDES. LA COUCHE EPONGE PRES DU TOIT DU MODELE COMPRENDRA 4 NIVEAUX AU LIEU D'UN SEUL NIVEAU. DANS CETTE COUCHE, LA DIFFUSION HORIZONTALE EST AUGMENTEE DANS LE BUT DE MINIMISER L'IMPACT NEGATIF D'ONDES REFLECHIES DE FACON IRREALISTE PAR LE TOIT. PARAMETRAGES PHYSIQUES LA CONFIGURATION PHYSIQUE DU MODELE DE PREVISION SERA EGALEMENT SUBSTANTIELLEMENT MODIFIEE COMPARATIVEMENT AU MODELE OPERATIONEL PRECEDENT. EN PARTICULIER, L'ENSEMBLE CONDENSATION-PRECIPITATION CHANGERA CONSIDERABLEMENT. LE SCHEMA DE CONVECTION PROFONDE DE KAIN-FRITSCH REMPLACERA LE SCHEMA DE KUO. CE CHANGEMENT PERMET UNE PLUS GRANDE CONTRIBUTION DU SCHEMA DE CONDENSATION QUI OPERE A L'ECHELLE DE LA MAILLE, CE QUI EST CONSISTANT AVEC L'AUGMENTATION DE LA RESOLUTION. IL S'AGIT DU SCHEMA DE SUNDQUIST QUI A ETE REVISE AFIN DE MIEUX REPRESENTER L'EVAPORATION DES PRECIPITATIONS SOUS LA BASE DES NUAGES, PHENOMENE QUI SERA DESORMAIS PRIS EN COMPTE SUR PLUSIEURS NIVEAUX. ENFIN, L'ENSEMBLE CONDENSATION-PRECIPITATION A ETE COMPLETE PAR L'INTRODUCTION D'UN SCHEMA DE CONVECTION RESTREINTE APPELE KUO TRANSIENT. LE SCHEMA DE SURFACE APPELE ISBA (INTERACTION SURFACE BIOSPHERE ET ATMOSPHERE) REMPLACE LE MODULE APPELE FORCE ET RESTORE. ISBA TRAITE LE SOL, LA VEGETATION, ET LA COUVERTURE NIVALE AVEC PLUS DE SOPHISTICATION. UN SYSTEME D'ASSIMILATION SEQUENTIEL DE DONNEES DE SURFACE TERRESTRE SERA IMPLANTE AFIN DE FOURNIR LES CONDITIONS INITIALES DE TEMPERATURE ET D'HUMIDITE DE SURFACE, LORS DU LANCEMENT DU MODELE. LA RESOLUTION ACCRUE DU MODELE ET ISBA RENDENT L'ANALYSE DE NEIGE PLUS PRECISE. NOTONS QUE L'ON UTILISERA LA FORMULATION DE BOUGEAULT ET LACARRERE POUR LA LONGUEUR DE MELANGE POUR LA DIFFUSION VERTICALE CAUSEE PAR LA TURBULENCE ATMOSPHERIQUE, CE QUI REPRESENTE UNE AMELIORATION CERTAINE EN PARTICULIER LORSQUE LA COUCHE LIMITE EST CONVECTIVEMENT ACTIVE ET BIEN MELANGEE. L'EFFICACITE COMPUTATIONNELLE DU SYSTEME D'ASSIMILATION DE DONNEES 4D-VAR A ETE AMELIOREE DE 40 AU TOTAL ET LES TEMPS DE COUPURE POUR L'INCLUSION DES OBSERVATIONS ONT ETE LEGEREMENT MODIFIES POUR LIVRER LES ANALYSES OPERATIONNELLES AVEC APPROXIMATIVEMENT LES MEMES TEMPS QU'AVANT. RESUME DES CHANGEMENTS AU SYSTEME GLOBAL D'ASSIMILATION DE DONNEES LES STATISTIQUES D'ERREUR DE PREVISION ONT ETE RECALCULEES SUR LES 58 NIVEAUX DU MODELE EN UTILISANT LA METHODE DITE DU NMC. DE MEME QUE DANS L'IMPLANTATION PRECEDENTE DU 4D-VAR, UN MODELE A BASSE RESOLUTION EST UTILISE AFIN DE PROPAGER LES INCREMENTS D'ANALYSE (T108) SUR LA FENETRE D'ASSIMILATION DE 6 HEURES. L'ENSEMBLE DE PARAMETRAGES PHYSIQUES DE CE MODELE A ETE MODIFIE DE LA MEME FACON QUE LE MODELE DE PREVISION DECRIT CI-HAUT. NOTONS TOUTEFOIS QUE L'ENSEMBLE DES PARAMETRAGES UTILISE AU SEIN DU LINEAIRE MODELE TANGENT AINSI QUE SON MODELE ADJOINT DEMEURENT LES MEMES. IMPACTS SUR LES SORTIES ET PRODUITS DERIVES TOUS LES PRODUITS ONT ETE GENERES ET VALIDES A PARTIR DES SORTIES DU NOUVEAU MODELE GLOBAL PENDANT LA PASSE PARALLELE. CERTAINS CHANGEMENTS ONT ETE APPORTES DANS L'ENSEMBLE DES CARTES POUR LA METEOROLOGIE POUR L'AVIATION. LES SEUILS DE TURBULENCE MODEREE ET SEVERE ONT ETE AUGMENTES POUR ETRE CONFORMES A CEUX UTILISES AVEC LE MODELE REGIONAL. DES MODIFICATIONS ESTHETIQUES ONT AUSSI ETE APPORTEES AUX CONTOURS DU NIVEAU DE CONGELATION ET DE LA HAUTEUR DE LA TROPOPAUSE. CONCERNANT LES CARTES 4-PANNEAUX CLASSIQUES, LA PRESSION AU NIVEAU MOYEN DE LA MER EST MAINTENANT FILTREE. LE FILTRAGE DU TOURBILLON ET DU MOUVEMENT VERTICAL A ETE ACCENTUE. LES CONTOURS DE 10 ET 30 POUR CENT D'HUMIDITE RELATIVE ONT ETE ELIMINES. TOUS LES AUTRES PRODUITS DE POST-TRAITEMENT ONT ETE VALIDES ET AUCUN PROBLEME N'A ETE NOTE. LE SYSTEME UMOS A ETE INCLUS AU TOUT DEBUT DE LA PASSE PARALLELE DU NOUVEAU MODELE GLOBAL, CE QUI A PERMIS A UMOS DE COMMENCER SA PERIODE D'ADAPTATION TOT DANS LE PROCESSUS DE TRANSITION DE MODELE. LES VERIFICATIONS DES TEMPERATURES UMOS BASEES SUR LE NOUVEAU MODELE GLOBAL INDIQUENT QUE LES ERREURS MOYENNES SONT SEMBLABLES EN AMPLITUDE A CE QUI EST NOTE DANS LES TEMPERATURES UMOS BASEES SUR L'ANCIEN MODELE GLOBAL, MAIS AVEC UN CYCLE DIURNE PLUS REALISTE. DE PLUS, L'ERREUR QUADRATIQUE MOYENNE DES TEMPERATURES UMOS BASEES SUR LE NOUVEAU MODELE GLOBAL EST DIMINUEE D'ENVIRON UN DEGRE CELSIUS A TOUS LES TEMPS DE PROJECTION PAR RAPPORT AUX SORTIES DIRECTES DU MODELE. LES PREVISIONS SCRIBE GENEREES EN MODE AUTOMATISE A PARTIR DES SORTIES DU NOUVEAU MODELE GLOBAL ONT ETE VERIFIEES EN PROFONDEUR. ON NOTE UNE AMELIORATION DES PREVISIONS SCRIBE POUR TOUS LES ELEMENTS DU TEMPS A TOUS LES TEMPS DE PROJECTION DU JOUR UN AU JOUR CINQ INCLUSIVEMENT, SAUF PEUT-ETRE POUR LA VITESSE DU VENT. IL EST A NOTER QUE SCRIBE A TENDANCE A PREVOIR DES VENTS UN PEU PLUS FORTS A PARTIR DU NOUVEAU MODELE GLOBAL QU'A PARTIR DE L'ANCIEN MODELE ET A SOUS-ESTIMER QUELQUE PEU LA FREQUENCE DE VENTS FAIBLES. CECI DIMINUE QUELQUE PEU LE POURCENTAGE DE PREVISIONS CORRECTES CALCULE A PARTIR DE TABLES DE CONTINGENCES. CEPENDANT, LA DIRECTION DES VENTS EST AMELIOREE DE FACON SIGNIFICATIVE. LES PROFILS A DES POINTS SPECIFIQUES TRANSMIS AUX BUREAUX REGIONAUX DANS LE FORMAT BUFR AURONT LA PLEINE RESOLUTION VERTICALE (58 NIVEAUX) DU NOUVEAU MODELE. CEPENDANT LES DONNEES AUX POINTS DE GRILLE EN FORMAT GRIB NE VERRONT PAS LEUR RESOLUTION AUGMENTEES DANS UN PREMIER TEMPS. MEME EN RESTANT A LEUR RESOLUTION ACTUELLE LES PRODUITS GRIB PROFITERONT DES GAINS DU NOUVEAU MODELE. LA FAISABILITE D'AUGMENTER LA RESOLUTION DES DONNEES GRIB A 33 KM SERA EVALUEE SELON LES BESOINS DES USAGERS ET LES RESSOURCES DE TRANSMISSION DISPONIBLES. LES PRODUITS OPERATIONNELS DU SYSTEME GLOBAL SERONT DISPONIBLES UN PEU PLUS TARD AVEC L'IMPLANTATION DU NOUVEAU MODELE GLOBAL SOIT APPROXIMATIVEMENT DE 40 A 55 MINUTES PLUS TARD QUE PRESENTEMENT. EN PARTICULIER LES MATRICES SCRIBE GLOBALES SERONT LIVREES 55 MINUTES PLUS TARD. NOUS SERONS EN MESURE DE CORRIGER CETTE SITUATION AVEC L'INSTALLATION D'UNE PLUS GRANDE PUISSANCE DE CALCUL AU DEBUT 2007. VERIFICATIONS OBJECTIVES ET SUBJECTIVES DES TESTS PRELIMINAIRES COMPLETS ONT ETE EFFECTUES SUR DES SITUATIONS D'HIVER ET D'ETE POUR EN ARRIVER A UNE CONFIGURATION FINALE. PAR LA SUITE LE MODELE ET LE CYCLE D'ASSIMILATION ONT TOURNE EN PARALLELE PENDANT 5 MOIS PENDANT LESQUELS IL A ETE COMPARE ET EVALUE OBJECTIVEMENT ET SUBJECTIVEMENT. DURANT LA PASSE PARALLELE, LE MODELE GLOBAL PARALLELE A GENERALEMENT BATTU LE MODELE OPERATIONNEL DE FACON SIGNIFICATIVE LORSQUE VERIFIE CONTRE LE RESEAU GLOBAL DES STATIONS DE RADIOSONDAGE. SUR L'AMERIQUE DU NORD, LES ERREURS QUADRATIQUES MOYENNES DES CHAMPS DE MASSE ONT ETE REDUITES DE FACON SIGNIFICATIVE, PARTICULIEREMENT POUR LES HAUTEURS GEOPOTENTIELLES ET LES TEMPERATURES POUR LES JOURS 1 A 5. LE SIGNAL POUR LES VENTS ETAIT EN FAVEUR DU MODELE PARALLELE AU NIVEAU DU COURANT-JET MAIS NEUTRE AUX NIVEAUX MOYENS ET ENFIN MOINS BON AUX BAS NIVEAUX. ON NOTE LES GAINS LES PLUS FORTS AUX TROPIQUES, MAIS LE NOUVEAU MODELE A BIEN FAIT DANS L'HEMISPHERE SUD ET EN ASIE. POUR CE QUI EST DES PRECIPITATIONS, LES MODELES ONT ETE EVALUES EN UTILISANT LE RESEAU SYNOPTIQUE ET LE RESEAU AMERICAIN A HAUTE DENSITE SHEF. LE MODELE GLOBAL PARALELE A DEMONTRE UNE NETTE AMELIORATION DANS LA CATEGORIE 0-0,2 MM, MONTRANT UNE PLUS GRANDE HABILITE A DISCRIMINER ENTRE LES SITUATIONS DE PRECIPITATIONS OU DE NON-PRECIPITATIONS. LE MODELE PARALLELE A AUSSI MIEUX REUSSI DANS LES CATEGORIES PLUS ELEVEES (25 MM). LE BIAIS DU NOUVEAU MODELE EST MEILLEUR POUR TOUTES LES CATEGORIES. SOMME TOUTE, LES PREVISIONS DE PRECIPITATIONS SONT BEAUCOUP AMELIOREES AVEC LE NOUVEAU MODELE. LE NOUVEAU SYSTEME A ETE EVALUE SUBJECTIVEMENT EN COMPARAISON DE L'ANCIEN SYSTEME. DURANT LA PASSE D'EVALUATION PARALLELE, LES SORTIES DU NOUVEAU SYSTEME GLOBAL ONT ETE PREFEREES AUTANT POUR LES CHAMPS DE MASSE QUE LES PREVISIONS DE QUANTITES DE PRECIPITATIONS. LE NOUVEAU MODELE EST PLUS ACTIF ET PREVOIT DES SYSTEMES PLUS CREUX ET INTENSES QUI SONT GENERALEMENT PLUS REALISTES ET CECI EST AUSSI VRAI POUR LES SYSTEMES TROPICAUX. LES TRAJECTOIRES DES OURAGANS ET LEURS TRANSITIONS AUX LATITUDES MOYENNES ONT ETE MIEUX PREVUES. LES QUANTITES ET LES PATRONS DE PRECIPITATIONS SONT NETTEMENT AMELIORES. IMPACT SUR LE MODELE REGIONAL L'EVALUATION OBJECTIVE DU MODELE REGIONAL PARALLELE EST NECESSAIRE PUISQU'IL SE NOURRIT DES ANALYSES DU CYCLE GLOBAL. LA VERIFICATION OBJECTIVE DES CHAMPS DE MASSE DU MODELE REGIONAL PARALLELE EN COMPARAISON DU MODELE REGIONAL OPERATIONNEL A MONTRE UN COMPORTEMENT NEUTRE POUR LE JOUR 1 MAIS UN GAIN FAIBLE MAIS CONSTANT POUR LE JOUR 2. LA VERIFICATION OBJECTIVE DES PRECIPITATIONS (QPF) NE MONTRE AUCUNE DIFFERENCE. LA VERIFICATION SUBJECTIVE MONTRE UN LEGER GAIN DU MODELE REGIONAL PARALLELE POUR LES CHAMPS DE MASSE DE MEME QUE POUR LES PRECIPITATIONS. LES DETAILS DE CETTE IMPLEMENTATION SERONT DISPONIBLE A PARTIR DU 30 OCTOBRE 2006 A L'URL SUIVANT: HTTP://WWW.SMC.EC.GC.CA/CMC/OP_SYSTEMS/RECENT_F.HTML POUR DES QUESTIONS SPECIFIQUES, S'ADRESSER A: PRODUCTION-INFO(AT)CMC.EC.GC.CA EVERELL / ADMA / SMA-SMC TORONTO