NOCN03 CWAO 141800 GENOT ADMIN. NO. 009 VERSION FRANCAISE DE CE GENOT EST NO. 010 MAJOR UPGRADE TO THE REGIONAL DETERMINISTIC PREDICTION SYSTEM (RDPS) AT THE CANADIAN METEOROLOGICAL CENTRE. ON TUESDAY NOVEMBER 18, 2014, STARTING WITH THE 1200 UTC RUN, THE METEOROLOGICAL SERVICE OF CANADA'S CANADIAN METEOROLOGICAL CENTRE (CMC) WILL IMPLEMENT IMPORTANT CHANGES TO THE REGIONAL DETERMINISTIC PREDICTION SYSTEM (RDPS). THE CURRENT VERSION 3.2.1 OF THE SYSTEM (HEREAFTER CALLED RDPS-3.2.1) WILL BE REPLACED BY THE NEW VERSION OF THE RDPS, THAT IS VERSION 4.0.0 (HEREAFTER CALLED RDPS-4.0.0). 1. BACKGROUND THE RDPS REPRESENTS THE MAIN NUMERICAL WEATHER PREDICTION (NWP) GUIDANCE FOR OUR USERS. IT PRODUCES 48-HOUR FORECASTS OVER NORTH AMERICA AT 00, 06, 12, AND 18 UTC. THE RDPS INCLUDES 2 DIFFERENT VERSIONS OF THE GEM MODEL. ONE IS A LIMITED AREA MODEL (LAM) CALLED THE RDPS-LAM WHICH COVERS NORTH AMERICA AND A LARGE PORTION OF THE ADJACENT OCEANS WITH AN APPROXIMATE HORIZONTAL GRID SPACING OF 10 KM. THIS RDPS-LAM PROVIDES THE REGIONAL FORECAST AND USES LATERAL BOUNDARY CONDITIONS PROVIDED BY A GLOBAL DRIVING MODEL CALLED THE RDPS-DRIVER. THE RDPS INTERMITTENT ASSIMILATION CYCLE IS INITIATED 6 HOURS PRIOR TO THE ANALYSIS TIME. THE OPERATIONAL GLOBAL DETERMINISTIC PREDICTION SYSTEM (GDPS) ANALYSIS PROVIDES INITIAL CONDITIONS FOR BOTH THE RDPS-DRIVER AND THE RDPS-LAM. BOTH MODELS ARE INTEGRATED FOR 9 HOURS TO SERVE AS THE BACKGROUND TRAJECTORY NECESSARY TO PRODUCE THE RDPS-DRIVER AND THE RDPS-LAM ANALYSES. SUBSEQUENTLY, AN RDPS-DRIVER 2-DAY FORECAST IS PERFORMED WHICH DRIVES THE RDPS-LAM 2-DAY FORECAST. 2. SUMMARY OF CHANGES THE FORECAST MODEL CONFIGURATIONS REMAIN THE SAME. THE ONLY MODIFICATION TO THE MODEL CODE IS THE CORRECTION OF A UNIT CONVERSION ERROR IN THE FORMULATION OF THE PROGNOSTIC EQUATIONS FOR THE SNOW CANOPY. THIS CORRECTION IN THE MODEL FORMULATION HAS A SIGNIFICANT IMPACT ON THE FORECASTED NEAR-SURFACE TEMPERATURE IN WINTER. ALSO, THE INTERMITTENT ASSIMILATION CYCLING STRATEGY OF THE RDPS REMAINS THE SAME. THE MAIN CHANGE TO THE RDPS IS THE REPLACEMENT OF THE LIMITED-AREA 4DVAR DATA ASSIMILATION ALGORITHM FOR THE LIMITED-AREA RDPS-LAM ANALYSIS BY A 4D ENSEMBLE-VARIATIONAL (4DENVAR) ASSIMILATION ALGORITHM. AS WELL, THE 3DVAR ASSIMILATION SCHEME FOR THE SYNCHRONOUS RDPS-DRIVER ANALYSIS IS REPLACED BY THE SAME 4D ENSEMBLE-VARIATIONAL (4DENVAR) ASSIMILATION ALGORITHM. FURTHER FORECAST IMPROVEMENTS ARE ALSO MADE POSSIBLE BY AN UPGRADE IN THE ASSIMILATED OBSERVATIONAL DATA AND BY INTRODUCING AN IMPROVED GLOBAL ANALYSIS IN THE INTERMITTENT ASSIMILATION CYCLE. THIS NEW GLOBAL ANALYSIS WILL BE IMPLEMENTED AT THE SAME TIME AS RDPS-4.0.0. FOR MORE INFORMATION, SEE THE GENOT RELATED TO THE IMPLEMENTATION OF GDPS-4.0.0. THE RDPS-4.0.0 WILL ALSO USE A NEW SEA-ICE CONCENTRATION ANALYSIS. 3. INTRODUCTION OF THE 4DENVAR RDPS-3.2.1, BASED ON 4D/3DVAR ALGORITHMS WITH CLIMATOLOGICAL BACKGROUND-ERROR COVARIANCES, IS REPLACED BY THE FOUR-DIMENSIONAL ENSEMBLE-VARIATIONAL (4DENVAR) DATA ASSIMILATION APPROACH. UNLIKE 4DVAR, THE NEW 4D ASSIMILATION APPROACH DOES NOT REQUIRE THE TANGENT LINEAR AND ADJOINT VERSIONS OF THE FORECAST MODEL, BUT INSTEAD RELIES ON 4D ENSEMBLE COVARIANCES TO EXPLICITLY ESTIMATE THE FULL TEMPORAL-SPATIAL BACKGROUND-ERROR COVARIANCES OVER THE ASSIMILATION TIME WINDOW. AS IN THE NEWLY IMPLEMENTED GDPS-4.0.0, THE BACKGROUND-ERROR COVARIANCES IN EACH ANALYSIS STEP (I.E. LAM AND DRIVER) OF THE RDPS ARE ESTIMATED FROM THE ENSEMBLE OF BACKGROUND STATES FROM THE OPERATIONAL GLOBAL ENSEMBLE KALMAN FILTER (ENKF). NOTE THAT AN UPGRADED VERSION OF THE OPERATIONAL ENKF WILL ALSO BE IMPLEMENTED AT THE SAME TIME AS RDPS-4.0.0. FOR MORE INFORMATION, SEE THE GENOT RELATED TO THE IMPLEMENTATION OF GEPS-4.0.0. BY REMOVING THE USE OF THE TANGENT LINEAR AND ADJOINT MODELS OF THE FORECAST MODEL FROM THE DATA ASSIMILATION PROCEDURE, THE 4DENVAR APPROACH IS MORE COMPUTATIONALLY EFFICIENT AND EASIER TO PARALLELIZE THAN 4DVAR. THE NEW RDPS-LAM ANALYSIS BASED ON 4DENVAR REQUIRES APPROXIMATIVELY 15 TIMES LESS COMPUTATIONAL RESOURCES THAN THE PREVIOUS 4DVAR-BASED ANALYSIS STEP. THIS IMPROVED EFFICICIENCY PERMITS AN INCREASE IN THE HORIZONTAL RESOLUTION OF THE ANALYSIS INCREMENT TO 0.45 X 0.45 DEGREES ON A GAUSSIAN GRID, AND THEY ARE NOW COMPUTED EVERY HOUR OVER THE 6 H ASSIMILATION WINDOW. 4. UPGRADES TO THE OBSERVATIONAL DATA ASSIMILATED ALL OF THE UPGRADES IN THE ASSIMILATED OBSERVATIONAL DATA DESCRIBED IN THIS SECTION ARE DONE BOTH IN THE RDPS-LAM AND THE RDPS-DRIVER ASSIMILATION PROCEDURES. 4.1 IMPROVED TREATMENT OF RADIOSONDE AND AIRCRAFT OBSERVATIONS IN THE 4DVAR SYSTEM, RADIOSONDE PROFILES WERE INTERPOLATED TO 27 PRESCRIBED PRESSURE LEVELS. FOR THE RDPS-4.0.0 UPGRADE, THE VERTICAL SELECTION OF RADIOSONDE AND AIRCRAFT DATA HAS BEEN UNIFIED. ONE SET OF OBSERVATIONS PER MODEL LAYER IS SELECTED, WHICH INCREASES THE VOLUME OF ASSIMILATED DATA BY ROUGHLY 50 PERCENT FOR RADIOSONDES AND 35 PERCENT FOR AIRCRAFT. A STATIC BIAS CORRECTION BASED ON THE REPORTED PRESSURE LEVEL IS APPLIED TO ALL TEMPERATURE OBSERVATIONS FROM AIRCRAFT REPORTS. THE OBSERVATION-ERROR STATISTICS HAVE ALSO BEEN REVISED FOR BOTH RADIOSONDE AND AIRCRAFT DATA. IN ALL PREVIOUS DATA ASSIMILATION SYSTEMS USED OPERATIONALLY AT THE CMC, THE UPPER-AIR STATION LOCATION AND VALIDITY TIME WERE FIXED FOR THE ENTIRE RADIOSONDE PROFILE. THIS IS BECAUSE THE ACTUAL HORIZONTAL POSITION AND TIME OF OBSERVATIONS ARE NOT PROVIDED IN THE RADIOSONDE REPORTS IN ALPHANUMERIC CODES AVAILABLE THROUGH THE GTS. IN THE NEW SYSTEM, THE BALLOON TRAJECTORY AND THE ACQUISITION TIME ARE ESTIMATED FROM THE OBSERVED WIND AND A REPRESENTATIVE ELAPSED ASCENDING TIME PROFILE. IN THE FUTURE, DIRECT METADATA WILL BE REPORTED IN BINARY UNIVERSAL FORM FOR THE REPRESENTATION OF METEOROLOGICAL DATA (B.U.F.R) CODE, WHICH WILL PROGRESSIVELY REPLACE THE CURRENT ALPHANUMERIC CODES FOR TRANSMITTING RADIOSONDE DATA. CONSEQUENTLY, THE MODIFICATIONS MADE HERE TO THE RADIOSONDE DATA PROCESSING WILL FACILITATE THE ONGOING TRANSITION FROM ALPHANUMERIC CODES TO B.U.F.R CODE. 4.2 ASSIMILATION OF GROUND-BASED GPS DATA GROUND-BASED GPS (GB-GPS) ZENITH TROPOSPHERIC DELAY (ZTD) OBSERVATIONS ARE INTRODUCED AS A NEW OBSERVATION TYPE IN RDPS- 4.0.0. ASSIMILATION OF ZTD DATA IN AN ANALYSIS SYSTEM SUPPLIES VALUABLE INFORMATION ON WATER VAPOR IN THE LOWER TO MID-TROPOSPHERE AT LOCALLY HIGH SPATIAL RESOLUTION AND FREQUENCY COMPARED TO RADIOSONDE OBSERVATIONS. THE ASSIMILATED GB-GPS DATA IS PROVIDED BY THE NOAA GLOBAL SYSTEMS DIVISION GPS NETWORK, COVERING NORTH AMERICA AND HAWAII. OBSERVATIONS ARE AVAILABLE EVERY 30 MINUTES AND INCLUDE ZTD PLUS COLLOCATED (OR NEARBY) SURFACE OBSERVATIONS OF PRESSURE, TEMPERATURE, AND RELATIVE HUMIDITY. 4.3 IMPROVED SATELLITE RADIANCE BIAS CORRECTION PROCEDURE THE RDPS PERFORMS A BIAS CORRECTION ON THE ASSIMILATED SATELLITE RADIANCES USING THE CORRECTION COEFFICIENTS CALCULATED IN THE GDPS. THE PROCEDURE USED IN GDPS-4.0.0 (IMPLEMENTED AT THE SAME TIME AS RDPS-4.0.0) TO CALCULATE THESE COEFFICIENTS HAS BEEN REVISED AND IMPROVED. FOR MORE INFORMATION, SEE THE GENOT RELATED TO THE IMPLEMENTATION OF GDPS-4.0.0. 4.4 ADDITIONAL AIRS/IASI CHANNELS ASSIMILATED IN PREVIOUS VERSIONS OF THE RDPS, ONLY 87 AIRS (FROM AQUA) AND 62 IASI (FROM METOP-A AND METOP-B) CHANNELS WERE ASSIMILATED. NO IASI MOISTURE CHANNELS IN THE 5.5-7.5 MICRON SPECTRAL REGION WERE ASSIMILATED. IN RDPS-4.0.0, 142 CHANNELS ARE ASSIMILATED FOR EACH INSTRUMENT, COVERING THE SPECTRAL DOMAIN 4.4-15.4 MICRONS AND, IN PARTICULAR, ABOUT 30 HIGH-PEAKING TEMPERATURE CHANNELS (70-150 HPA) ARE ADDED. 4.5 OTHER CHANGES TO RADIANCE ASSIMILATION SATELLITE RADIANCE OBSERVATION-ERROR STATISTICS FOR ASSIMILATION PURPOSES ARE REVISED. IN RDPS-4.0.0, ERRORS ARE DEFINED BY A PREDETERMINED INSTRUMENT- AND CHANNEL-DEPENDENT FACTOR F MULTIPLIED BY THE STD DEV OF THE OBSERVATION-BACKGROUND DIFFERENCES. HOWEVER, THE CHOSEN VALUES FOR F RESULT IN OBSERVATION-ERROR STATISTICS FOR MOST CHANNELS THAT ARE SIMILAR TO THOSE USED IN THE PREVIOUS SYSTEM. THE FAST RADIATIVE TRANSFER MODEL USED FOR RADIANCE ASSIMILATION, RTTOV, IS UPDATED FROM VERSION 8.7 TO 10.2. 5. NEW SEA-ICE CONCENTRATION ANALYSIS A NEW GLOBAL SEA-ICE CONCENTRATION ANALYSIS IS USED BY THE ATMOSPHERIC MODEL. THE NEW SYSTEM USES A 3DVAR APPROACH TO ASSIMILATE ICE CONCENTRATION RETRIEVED FROM PASSIVE MICROWAVE SATELLITE OBSERVATIONS (SSMI AND SSMIS) AND FROM THE MANUAL ICE CHARTS PRODUCED BY THE CANADIAN ICE SERVICE. THE SYSTEM USES A 10 KM GRID SPACING AND PERFORMS 4 ANALYSES PER DAY. 6. PERFORMANCE EVALUATION DURING R AND D PHASE THE NEW RDPS WAS TESTED EXTENSIVELY. MANY CYCLES EACH COVERING AT LEAST TWO SUMMER MONTHS AND TWO WINTER MONTHS WERE PERFORMED AND EVALUATED DURING THE DEVELOPMENT PHASE. FOR THE FINAL TESTS, OBJECTIVE VERIFICATION OF UPPER AIR FORECASTS AGAINST RADIOSONDE DATA SHOWS A SIGNIFICANT IMPROVEMENT AT ALL FORECAST LEAD-TIMES. THIS IS GENERALLY TRUE FOR ALL SEASONS TESTED AND FOR ALL REGIONS AND VARIABLES. FOR THE FINAL TESTS, OBJECTIVE VERIFICATION OF SURFACE FIELDSAGAINST METAR AND SYNOPTIC OBSERVATION DATA WERE PERFORMED. WHILE SOME IMPROVEMENTS CAN BE SEEN IN SUMMER, THE LARGEST IMPROVEMENTS CAN BE SEEN IN WINTER DUE TO THE BUG CORRECTION IN THE PROGNOSTIC EQUATIONS OF THE SNOW CANOPY DENSITY IN THE MODEL FORMULATION. PRECIPITATION ACCUMULATIONS WERE ALSO VERIFIED. AGAIN, SOME IMPROVEMENTS CAN BE SEEN AT MOST FORECAST LEAD TIMES AND IN EACH SEASON, ALTHOUGH MANY ARE BARELY STATISTICALLY SIGNIFICANT. 7. PERFORMANCE EVALUATION DURING THE PARALLEL RUN PHASE THE NEW SYSTEM WAS RUN IN PARALLEL FOR A FOUR MONTH PERIOD FROM 15 JULY 2014 UNTIL NOVEMBER 2014. THE OBJECTIVE EVALUATION OF THE PARALLEL RUN COMPARED TO THE OPERATIONAL SYSTEM SHOWED SIMILAR IMPROVEMENTS TO WHAT WAS OBSERVED DURING THE R AND D PHASE. THE NEW SYSTEM WAS ALSO EVALUATED ON A DAILY BASIS BY THE A AND P OPERATIONAL METEOROLOGISTS. IN THE SHORT TERM, RESULTS SHOWED LITTLE DIFFERENCES COMPARED TO THE OPERATIONAL SYSTEM FOR THE VERIFICATION OF THE GEOPOTENTIAL HEIGHT AT 500 HPA AND SEA-LEVEL PRESSURE. THE DIFFERENCES WERE MORE NOTICEABLE AT 36 HOURS AND MORE SIGNIFICANT AT 48 HOURS IN FAVOUR OF THE PARALLEL SYSTEM. AT 48-HOUR LEAD TIME, NEARLY TWO-THIRDS OF THE TIME, THE TWO MODELS WERE JUDGED TO BE EQUIVALENT, EITHER WITH THE CORRECT SOLUTION OR NOT. THE REMAINING THIRD OF THE TIME, THE NEW RDPS FORECAST WAS PREFERRED OVER THE OPERATIONAL SOLUTION BY A SMALL MARGIN. WHEN CONSIDERING THE VERIFICATION BY REGION, A SLIGHT GAIN WAS NOTED FOR THE RDPS IN PARALLEL OVER THE PACIFIC AND SLIGHTLY MORE OVER CENTRAL NORTH AMERICA. IT IS OVER THE ATLANTIC REGIONS WHERE WE SAW A MORE SIGNIFICANT GAIN WITH THE RDPS IN PARALLEL. WHERE THE OPERATIONAL RDPS AND THE NEW RDPS WERE DIFFERENT, TWO THIRDS OF THE CASES WERE IN FAVOUR OF THE RDPS-4.0.0 SOLUTION. TIMING AND INTENSITY OF SYSTEMS WERE HANDLED BETTER BY THE NEW SYSTEM OVER THE ATLANTIC REGIONS, WHICH HAD A POSITIVE IMPACT FOR QPF AS WELL. THE SUBJECTIVE VERIFICATIONS ALSO SHOW SLIGHT GAINS WITH THE 4DENVAR OVER THE ARCTIC. THIS IS EVEN MORE PRONOUNCED AT 500 HPA. RESULTS FOR THE QPF SHOWED A MORE PRONOUNCED SIGNAL IN FAVOUR OF RDPS-4.0.0 OVER THE ATLANTIC REGION, A SIMILAR PERFORMANCE OF BOTH SYSTEMS OVER CENTRAL REGIONS, AND A SOMEWHAT BETTER PERFORMANCE OF THE PARALLEL SYSTEM OVER THE PACIFIC REGION. 9. AVAILABILITY OF PRODUCTS WITH THIS UPDATE, THEY ARE NO CHANGES TO THE TIMING OR OFFERING OF PRODUCTS. FOR MORE DETAILS PLEASE REFER TO THE TECHNICAL NOTE AVAILABLE VIA THE FOLLOWING LINK (SEE THE ENTRY REFERRING TO RDPS-4.0.0): HTTP://COLLABORATION.CMC.EC.GC.CA/CMC/CMOI/PRODUCT_GUIDE/DOCS/CHANG ES_E.HTML (THE LINK MUST BE TYPED IN LOWERCASE) FOR QUESTIONS REGARDING THE NEW RDPS-4.0.0 AND ITS ASSOCIATED OUTPUT AND PRODUCTS, OR OTHER SPECIFIC QUESTIONS CONCERNING THIS OPERATIONAL IMPLEMENTATION, YOU CAN WRITE TO (USING LOWER CASE): PRODUCTION-INFO(AT)CMC.EC.GC.CA GRIMES / ADM-MSC / SMA-SMC END