NOCN03 CWAO 142110 GENOT ADMIN NO. 011 VERSION FRANCAISE DE CE GENOT EST NO. 012 UPGRADE TO THE GLOBAL DETERMINISTIC PREDICTION SYSTEM (GDPS) AT THE CANADIAN METEOROLOGICAL CENTRE ON TUESDAY SEPTEMBER 18, 2018, STARTING WITH THE 1200 UTC RUN, THE CANADIAN METEOROLOGICAL CENTER (CMC) OF THE METEOROLOGICAL SERVICE OF CANADA (MSC) WILL IMPLEMENT VERSION 6.1.0 OF ITS GLOBAL DETERMINISTIC PREDICTION SYSTEM (GDPS), HEREAFTER GDPS-6.1.0. THE MAIN CHANGES ARE IN THE DATA ASSIMILATION COMPONENT. THIS INCLUDES THE OPTIMAL USE OF A FEW TYPES OF OBSERVATIONS WITH A SLIGHT INCREASE OF THE DAILY QUANTITY OF ASSIMILATED INFORMATION. OTHER CHANGES ENABLE A BETTER USE OF THE NEW CRAY SUPERCOMPUTER AND TO BENEFIT SIMULTANEOUSLY FROM THE MODEL MODIFICATIONS OF THE GLOBAL ENSEMBLE PREDICTION SYSTEM (GEPS) IN THE 4D-ENVAR ANALYSIS SYSTEM. THE RADIATIVE TRANSFER MODEL RTTOV HAS ALSO BEEN UPDATED. ALL THESE CHANGES ARE DESCRIBED BRIEFLY HEREAFTER. 1. CHANGES TO THE MODEL COMPONENT OF THE GDPS NO CHANGES WERE MADE TO THE MODEL. 2. CHANGES TO THE DATA ASSIMILATION COMPONENT OF THE GDPS 2.1 CHANGES IN REGARDS TO A FEW TYPES OF OBSERVATIONS THE DATA ASSIMILATION COMPONENT WAS MODIFIED TO ENABLE AN OPTIMAL USE OF THE FOLLOWING TYPES OF OBSERVATIONS: - ADDITION OF AMV (ATMOSPHERIC MOTION VECTOR) WIND OBSERVATIONS FROM THE DUAL-METOP SATELLITE AND UPGRADE OF THE PROCESSING AND ASSIMILATION OF AMV. THIS INCLUDES A NEW SELECTION ALGORITHM WHICH ENABLES THE USE OF HOURLY OBSERVATIONS FROM GEOSTATIONNARY SATELLITES AND A BETTER DISTRIBUTION OF OBSERVATIONS IN SPACE AND TIME. IN ADDITION, THE SITUATION DEPENDENT OBSERVATION ERROR ALGORITHM FROM FORSYTHE AND SAUNDERS (2008), WHICH TAKES INTO ACCOUNT BOTH TRACKING AND HEIGHT ASSIGNMENT ERRORS, WAS IMPLEMENTED. - IMPROVEMENTS TO THE QUALITY CONTROL AND ASSIMILATION OF GROUND- BASED GPS (GB-GPS) OBSERVATIONS INCLUDING THE SPECIFICATION OF NEW OBSERVATION ERRORS. - IMPROVEMENTS OF THE PROCESSING AND ASSIMILATION OF RADIOSONDE OBSERVATIONS. THIS INCLUDES A TAC (TRADITIONAL ALPHANUMERIC CODE) VS BUFR (BINARY UNIVERSAL FORM FOR THE REPRESENTATION OF METEOROLOGICAL DATA) SELECTION SCHEME WHICH ALLOWS ADDITIONAL RADIOSONDES ORIGINATING FROM THE BUFR FORMAT TO BE ASSIMILATED, THE INTRODUCTION OF A REJECTION CRITERIA FOR HUMIDITY OBSERVATIONS AND A REVISED SATURATION WATER VAPOUR PRESSURE FORMULA. - ASSIMILATION OF ALL AVAILABLE CHANNELS SENSITIVE TO WATER VAPOUR (BETWEEN 1 AND 3) FROM GEOSTATIONNARY SATELLITES. 2.2 CHANGES TO THE DATA ASSIMILATION SYSTEM CONSIDERING THE INTERDEPENDENCY BETWEEN THE GDPS 4D-ENVAR ANALYSIS AND GEPS, THE DATA ASSIMILATION SYSTEM WAS ADAPTED TO THE FOLLOWING ASPECTS IN ORDER TO BENEFIT FROM THE MODEL MODIFICATIONS OF THE LATTER: - THE HORIZONTAL GRID RESOLUTION OF THE ANALYSIS INCREMENTS HAS INCREASED FROM 50 KILOMETERS TO AN EFFECTIVE RESOLUTION OF 39 KILOMETERS: - THE ENSEMBLE-BASED BACKGROUND ERROR COVARIANCES ARE USED TO THE EXTENDED 0.1 HPA LEVEL - THE RELATIVE WEIGHT GIVEN TO THE ENSEMBLE-BASED COVARIANCE AND THE STATIC COVARIANCE MATRICES HAVE CHANGED TO 75 PERCENT (2/3) AND 37.5 (1/3) RESPECTIVELY. MOREOVER, THE 4D-ENVAR FORTRAN CODE WAS SIGNIFICANTLY MODIFIED TO IMPROVE ITS EFFICIENCY ON THE CRAY XC40 SUPERCOMPUTER. FINALLY, THE RADIATIVE TRANSFER MODEL RTTOV USED AS AN OBSERVATION OPERATOR FOR RADIANCES WAS UPDATED TO VERSION 12.1, WHICH WILL PROVIDE ALL THE BENEFITS, AS A RESULT, FROM THE LATEST SPECTROSCOPIC IMPROVEMENTS. 3. PERFORMANCE EVALUATION DURING THE RESEARCH AND DEVELOPMENT (R AND D ) PHASE -OBJECTIVE SCORES THE UPDATED GDPS-6.1.0 PROVIDES IMPROVED ACCURARY RELATIVE TO THE PREVIOUS SYSTEM (GDPS-6.0.0), BASED ON RESULTS FROM TWO SETS - SUMMER 2016 AND WINTER 2017 - OF TWO-MONTH EXPERIMENTS. TEMPERATURE, WINDS AND HUMIDITY FIELDS WERE COMPARED TO RADIOSONDE OBSERVATIONS AND ERA5 REANALYSIS FROM ECMWF. AT THE SURFACE, TEMPERATURES WERE COMPARED TO SYNOPTIC STATIONS AND QUANTITATIVE PRECIPITATION FORECASTS (QPF) WERE COMPARED TO OBSERVATIONS USED IN THE REGIONAL DETERMINISTIC PRECIPITATION ANALYSIS (RDPA). 3.1 IMPACT OF THE MODEL COMPONENT CHANGES NO CHANGES WERE MADE TO THE MODEL COMPONENT. 3.2 IMPACT OF THE ASSIMILATION COMPONENT CHANGES THE IMPACT OF THE CHANGES TO THE 4D-ENVAR, THE UPGRADE OF RTTOV, THE USE OF ADDITIONAL RADIOSONDES ORIGINATING FROM BULLETINS IN BUFR FORMAT AND THE OPTIMAL USE OF GB-GPS OBSERVATIONS IS POSITIVE ON THE SHORT AND MEDIUM RANGE FORECASTS FOR BOTH TEST PERIODS ON BOTH HEMISPHERES. THE OPTIMAL USE OF AMVS, THE INTRODUCTION OF A REJECTION CRITERA FOR HUMIDITY OBSERVATIONS FROM RADIOSONDES AND THE ADDITIONAL WATER VAPOR CHANNELS FROM CSR OBSERVATIONS ARE OVERALL POSIVITE EXCEPT FOR A FEW LOCALIZED DETERIORATIONS. 3.3 FINAL RESEARCH AND DEVELOPMENT TEST SERIES THE STANDARD DEVIATION IS GENERALLY REDUCED FOR THE GDPS-6.1.0, WHEN COMPARED TO THE GDPS-6.0.0, FOR BOTH SEASONS, IN BOTH HEMISPHERES AND AT ALMOST ALL LEVELS. THIS IS MOST NOTICEABLE IN THE SOUTHERN HEMISPHERE AND DUE MAINLY TO THE OPTIMAL USE OF AMVS AS WELL AS THE UPGRADE OF RTTOV. IN THE NORTHERN HEMISPHERE, DURING THE SUMMER PERIOD, THE INTRODUCTION OF A REJECTION CRITERION FOR HUMIDITY OBSERVATIONS FROM RADIOSONDES CLEARLY IMPROVES THE RELATIVE HUMIDITY FIELD AT 150 HPA, HOWEVER THE GEOPOTENTIAL HEIGHT DETERIORATES AT MEDIUM RANGE, IMPACT DOMINATED BY THE EUROPEAN REGION. IN THE TROPICAL REGION, THE IMPACT IS RATHER NEUTRAL. TEMPERATURE BIASES ARE SOMETIMES POSITIVE SOMETIMES NEGATIVE BUT IS SIGNIFICANTLY REDUCED NEAR THE TROPOAUSE IN THE NORTHERN HEMISPHERE, MOSTLY IN WINTER. THIS REDUCTION IS PARTICULARLY DUE TO THE INTRODUCTION OF A REJECTION CRITERION OF HUMIDITY OBSERVATIONS FROM RUSSIAN RADIOSONDES. THE VERIFICATION AGAINST SURFACE OBSERVATIONS IS NEUTRAL GLOBALLY. FOR SHORT RANGE FORECASTS, IN NORTH AMERICA, TEMPERATURE BIASES SHOW A SLIGHT IMPROVEMENT IN SUMMER AND SLIGHT DETERIORATION IN WINTER. 4. PERFORMANCE EVALUATION RESULTS DURING THE PARALLEL RUN THE UPDATED GDPS-6.1.0 PROVIDES IMPROVED FORECAST ACCURACY RELATIVE TO THE PREVIOUS SYSTEM (GDPS-6.0.0), BASED ON RESULTS FROM A PARALLEL RUN EXECUTED DURING THE SPRING AND SUMMER OF 2018. 4.1 OBJECTIVE SCORES THE PARALLEL RUN WAS COMPARED AGAINST GPDS VERSION 6.0.0, WHICH WAS OPERATIONAL AT THE TIME OF TESTING. TEMPERATURE, WINDS AND HUMIDITY VARIABLES WERE COMPARED TO RADIOSONDE OBSERVATIONS AND MODEL ANALYSIS. AT THE SURFACE, VARIOUS VARIABLES WERE COMPARED AGAINST SYNOPTIC STATIONS, AND QUANTITATIVE PRECIPITATION FORECASTS (QPF) WERE COMPARED TO OBSERVATIONS USED IN THE RDPA. - THESE SCORES SHOWED A SUBSTANCIAL IMPROVEMENT IN PERFORMANCE IN BOTH EXTRATROPICAL REGIONS FOR THE GEOPOTENTIAL HEIGHT FORECASTS UP TO MEDIUM-RANGE LEAD TIMES FROM THE SURFACE UP TO THE MODEL TOP. IN THE NORTHERN HEMISPHERE, THE IMPROVEMENT PERSISTS, TO A LESSER EXTENT, FOR LONG LEAD TIMES (DAYS 7 TO 10) WHILE IN SOUTHERN HEMISPHERE, RESULTS ARE MIXED. IN THE TROPICS, SCORES ARE GLOBALLY NEUTRAL : - IN BOTH EXTRATROPICAL REGIONS, TEMPERATURE AND WIND FORECASTS ALSO SHOW IMPROVEMENTS FOR MOST OF THE LEVELS INCLUDING SEVERAL STATISTICALLY SIGNIFICANT ONES OUT TO DAYS 6 TO 10 IN SOME CASES : - IN NORTH AMERICA, SURFACE VERIFICATION OF TEMPERATURE, DEW POINT TEMPERATURE, SEA LEVEL PRESSURE AND WINDS SHOWED IMPROVEMENTS IN STANDARD DEVIATION FOR DAYS 3 TO 5. - FOR THE QPF, THE FREQUENCY BIAS INDEX SHOWED A DETERIORATION FOR NORTH AMERICA IN THE FORECAST OF ACCUMULATION OF MORE THAN 25 MM FOR DAYS 4 AND 5. 4.2 SUBJECTIVE EVALUATION THE GDPS-6.1.0 IN PARALLEL MODE WAS ASSESSED BY A TEAM OF OPERATIONAL METEOROLOGISTS FROM THE ANALYSIS AND PROGNOSIS (A AND P) SECTION OF CMC DURING MOST OF SPRING AND SUMMER 2018, FOR A TOTAL OF 166 DAYS AND 232 FORECASTS. THEIR ASSESSMENT OF MEAN SEA LEVEL PRESSURE, MADE OVER MOST OF NORTH AMERICA AND ADJACENT WATERS FOR LEAD TIMES UP TO 7 DAYS, SHOWED THAT GDPS-6.1.0 PERFORMED BETTER GLOBALLY AT ALL LEAD TIMES THAN GDPS- 6.0.0. MORE SPECIFICALLY IT WAS NOTED THAT: - THE PARALLEL GDPS WAS CONSIDERED TO PROVIDE A BETTER FORECAST FOR 43 PERCENT OF THE EVALUATIONS WHILE THE OPERATIONNAL GDPS WAS CHOSEN AS THE BEST SOLUTION IN 32 PERCENT OF EVALUATIONS. IN 25 PERCENT OF CASES, BOTH MODELS WERE CONSIDERED TO OFFER SOLUTIONS OF EQUAL VALUE: - FOR THE TWO TROPICAL SYSTEMS THAT AFFECTED CANADA DURING THE PERIOD OF EVALUATION, ALBERTO AND CHRIS, THE PARALLEL GDPS VERIFIED BETTER: - IN WELL-ORGANIZED SYNOPTIC SYSTEMS THE PARALLEL GDPS MANAGES TO ADJUST TO A BETTER SOLUTION FASTER THAN THE OPERATIONNAL GDPS. 4.3 IMPACT ON DEPENDENT SYSTEMS - UMOS : FOR GPDS-6.1.0, IT WAS DECIDED TO INSTALL THE UMOS SYSTEM WITHOUT TRAINING. VERIFICATIONS PERFORMED ON FORECASTS ISSUED DURING THE PARALLEL RUN SHOW THAT UMOS CONTINUES TO IMPROVE SIGNIFICANTLY THE ACCURACY OF THE NUMERICAL FORECASTS. FOR 20 PERCENT OF THE STATIONS, THE IMPROVEMENT IS MARGINAL BUT REMAINS POSITIVE FOR ALL CASES. - SCRIBE: IN SCRIBE MATRICES, PROBABILITIES OF PRECIPITATION COME FROM A SAMPLING METHOD APPLIED TO MODEL PRECIPITATION OUTPUT. CLOUD FORECASTS COME DIRECTLY FROM THE DIAGNOSTIC MODEL FORECAST WITH SOME SPATIAL AVERAGING. THESE TWO METHODS REPLACE THE PERFECT PROG STATISTICAL EQUATIONS. WHERE UMOS FORECASTS ARE NOT DIRECTLY AVAILABLE, TEMPERATURE FORECASTS COME FROM AN OPTIMAL INTERPOLATION BETWEEN NEIGHBOURING UMOS FORECASTS AND MODEL TEMPERATURES. THIS TECHNIQUE REPLACES THE OLDER KRIGING INTERPOLATION USING ONLY UMOS TEMPERATURES. VERIFICATION RESULTS SHOW THAT THESE CHANGES GENERALLY IMPROVE FORECASTS OF PROBABILITIES OF PRECIPITATION, CLOUD AND TEMPERATURE. 12Z MATRICES ARE ALSO EXTENDED TO 144 HOURS, JUST LIKE THE CURRENT 00Z ONES, WHICH IMPROVES FORECASTS QUALITY FOR DAYS 3 TO 5. - OTHER DEPENDENTS PREDICTION SYSTEMS: NO ADVERSE IMPACTS WERE NOTED DURING PARALLEL RUNS OF THE CANADIAN SEASONAL TO INTER-ANNUAL PREDICTION SYSTEM (CANSIPS) NOR THE GLOBAL DETERMINISTIC WAVE PREDICTION SYSTEM (GDWPS). THE GLOBAL ENSEMBLE PREDICTION SYSTEM (GEPS) IS INTERDEPENDENT WITH THE GDPS THROUGH THEIR RESPECTIVE ASSIMILATION SYSTEMS. CHANGES WERE INTRODUCED IN THE GEPS, CONCURRENT TO THOSE IN THE GDPS, AND ARE DESCRIBED IN GENOT NO. 009, ISSUED THE SAME DAY. 5. AVAILABILITY OF PRODUCTS WITH THIS UPDATE, THERE ARE NO CHANGES TO THE TIMING AND OFFERING OF PRODUCTS FROM THE GLOBAL DETERMINISTIC PREDICTION SYSTEM. FOR A COMPLETE DESCRIPTION OF THE CHANGES, PLEASE REFER TO THE TECHNICAL NOTE WHICH WILL BE AVAILABLE ON SEPTEMBER 18 VIA THE FOLLOWING LINK (SEE THE ENTRY REFERRING TO GDPS-6.1.0): HTTP://COLLABORATION.CMC.EC.GC.CA/CMC/CMOI/PRODUCT_GUIDE/DOCS/ CHANGES_E.HTML (LINK MUST BE TYPED ON A SINGLE LINE IN LOWERCASE) FOR QUESTIONS REGARDING THE NEW GDPS-6.1.0 AND ITS ASSOCIATED OUTPUT AND PRODUCTS, OR OTHER SPECIFIC QUESTIONS CONCERNING THIS OPERATIONAL IMPLEMENTATION, YOU CAN WRITE TO (USING LOWER CASE): EC.PRODUCTION-INFO.EC(AT)CANADA.CA GRIMES / ADM-MSC / SMA-SMC END