NOCN03 CWAO 201830 GENOT NO. 007 LE GENOT NO. 008 EST LA VERSION FRANCAISE DU GENOT NO 007. IMPROVEMENTS TO THE GLOBAL AND REGIONAL DATA ASSIMILATION SYSTEMS AT CMC. AS OF TUESDAY SEPTEMBER 21 2004 AT 1200 UTC, THE FOLLOWING CHANGES TO THE GLOBAL AND REGIONAL DATA ASSIMILATION SYSTEMS WILL BE IMPLEMENTED AT THE CANADIAN METEOROLOGICAL CENTRE. SUMMARY OF CHANGES NEW OBSERVATIONS WILL BE INCORPORATED IN THE 3D-VAR (3-DIMENSIONAL VARIATIONAL) DATA ASSIMILATION SYSTEM. FIRST, IR RADIANCE DATA FROM THE 6.7 MICRON CHANNEL FROM THE GOES-12 (EAST) SATELLITE WILL BE INCORPORATED, IN ADDITION TO THE GOES-10 (WEST) DATA WHICH IS ALREADY USED. ALSO, DATA FROM THE AMSUA INSTRUMENT ONBOARD THE NASA AQUA SATELLITE WILL ALSO BE ASSIMILATED. THIS WILL COMPLEMENT THE AMSUA DATA ALREADY USED FOR THE NOAA-15 AND NOAA-16 SATELLITES AND WILL PARTLY COMPENSATE FOR THE LOSS OF THE AMSUA INSTRUMENT FOR NOAA-17 WHICH OCCURRED IN LATE OCTOBER 2003. THERE ARE ALSO SOME CHANGES TO THE ATOVS (AMSUA AND AMSUB) THINNING PROCESS AND THE VARIATIONAL QUALITY CONTROL WILL ALSO BE APPLIED TO ATOVS DATA. A THIRD CHANGE IS THE INCORPORATION OF SATELLITE WINDS IN THE POLAR REGIONS OBTAINED FROM THE MODIS INSTRUMENT ONBOARD THE NASA AQUA AND TERRA SATELLITES. MODIFICATIONS TO THE DATA SELECTION AIMING AT INCREASING THE NUMBER OF SATELLITE WINDS FROM THE GOES-P SATELLITE ARE ALSO INCLUDED. FINALLY, DATA FROM SELECTED USA WIND PROFILERS WILL ALSO BE ASSIMILATED. THESE NEW DATASETS WILL BE INCORPORATED IN BOTH THE GLOBAL AND REGIONAL DATA ASSIMILATION SYSTEMS. THERE IS NO OTHER CHANGE TO THE NWP MODELS OR TO THE DATA ASSIMILATION SYSTEM. ADDITIONAL TECHNICAL INFORMATION ABOUT THE DATA AND THE ASSIMILATION PROCEDURES WILL BE FOUND ON THE MSC WEB SITE HTTP://WWW.SMC-MSC.EC.GC.CA/CMC/OP_SYSTEMS/RECENT_E.HTML (IN LOWER CASE). PERFORMANCE EVALUATION THIS INCORPORATION OF NEW DATASETS IN THE DATA ASSIMILATION SYSTEMS HAS BEEN TESTED ON A LARGE NUMBER OF CASES. DATA ASSIMILATION CYCLES FOR THE 2 MONTH PERIOD OF 11 DECEMBER 2003 TO 10 FEBRUARY 2004 HAVE BEEN PERFORMED. THE NEW SYSTEM HAS ALSO BEEN RUNNING IN PARALLEL SINCE LATE JUNE. ANALYSES AND FORECASTS FROM THE PARALLEL GLOBAL AND REGIONAL SYSTEMS HAVE BEEN VERIFIED AGAINST RADIOSONDE DATA OVER SEVERAL OBSERVATIONAL NETWORKS AS WELL AS AGAINST ANALYSES, AND EVALUATED BY CMC OPERATIONAL METEOROLOGISTS. ASSIMILATION THIS CHANGE REPRESENTS A SMALL BUT POSITIVE STEP TOWARD THE ASSIMILATION OF NEW DATASETS. IMPACTS ON THE ANALYSES ARE SMALL AND OPERATIONAL METEOROLOGISTS DID NOT NOTICE ANY SUBSTANTIAL DIFFERENCE BETWEEN THE OPERATIONAL AND PARALLEL ANALYSES. HOWEVER, THE ADDITION OF THESE NEW DATASETS IMPROVES THE ROBUSTNESS OF THE ASSIMILATION SYSTEM IN THE EVENT OF THE LOSS OF SOME OPERATIONAL DATA. THE ABOVE CONCLUSIONS APPLY FOR BOTH WINTER AND SUMMER SITUATIONS. GLOBAL MODEL FORECASTS OBJECTIVE VERIFICATION HAS SHOWN SMALL BUT CLEAR IMPROVEMENTS IN THE MASS AND WIND FIELDS, PARTICULARLY OVER NORTH AMERICA. THE IMPROVEMENT WAS SOMEWHAT LARGER BEYOND DAY 3. THE REGIONS SHOWING THE MOST IMPROVEMENTS WERE THE ARCTIC AND THE PACIFIC AREAS. THESE ARE THE AREAS WHERE THERE ARE LESS CONVENTIONAL OBSERVATIONS AND WHERE THE ADDITION OF SATELLITE DATA CAN CONTRIBUTE THE MOST. VERIFICATION OF QPF DID NOT INDICATE ANY SIGNIFICANT DIFFERENCE UP 48 HOURS. OPERATIONAL METEOROLOGISTS COMPARED THE TWO MODELS DURING THE PARALLEL RUN PERIOD. GENERALLY, THEY INDICATED THAT THE TWO SYSTEMS ARE OFTEN (65 PERCENT) SIMILAR BUT THEY PREFERRED THE PARALLEL MORE OFTEN THAN THE OPERATIONAL. IN THE ARCTIC AND PACIFIC AREAS, THEY PREFERRED THE PARALLEL 3 TIMES OUT OF 5 CASES SHOWING DIFFERENCES. THEY ALSO NOTED THAT THE RESULTS WERE MORE NEUTRAL OVER THE CONTINENT AND THE EAST COAST WHERE BOTH SYSTEMS WERE PREFERRED THE SAME NUMBER OF TIMES. FOR QPF, THE EVALUATION ALSO INDICATED A SLIGHT PREFERENCE FOR THE PARALLEL IN CASES SHOWING DIFFERENCES. OVERALL, THE CMC OPERATIONAL METEOROLOGISTS JUDGED THE PARALLEL CONFIGURATION BETTER. REGIONAL MODEL FORECASTS ALTHOUGH THE NEW DATASETS HAVE ALSO BEEN INCORPORATED INTO THE REGIONAL DATA ASSIMILATION SYSTEM, THE SHORT CUT-OFF TIME OF THE REGIONAL GEM FORECAST RUN (T+1H35) RESULTS IN MUCH LOWER DATA AVAILABILITY, ESPECIALLY FOR SATELLITE DATA. THEREFORE THE IMPACT IS SOMEWHAT SMALLER THAN FOR THE GLOBAL SYSTEM. NONETHELESS, OBJECTIVE VERIFICATION DID SHOW A SMALL BUT POSITIVE IMPACT ON THE MASS FIELD, AGAIN WITH MORE IMPACT OVER THE ARCTIC AND PACIFIC AREAS. FOR QPF, OBJECTIVE VERIFICATION DID NOT SHOW ANY SIGNIFICANT DIFFERENCE. THE OPERATIONAL METEOROLOGISTS EVALUATED THE PARALLEL CONFIGURATION MASS FIELDS SLIGHTLY BETTER BEYOND 24 HOURS, PARTICULARLY IN THE ARCTIC AND PACIFIC AREAS. IN THE ARCTIC AREAS, THE PARALLEL WAS PREFERRED TWICE OUT OF 3 CASES SHOWING DIFFERENCES. NO CLEAR CONCLUSION COULD BE DRAWN FROM THE QPF ASSESSMENT. OVERALL, SINCE THE MASS AND WIND FIELD FORECASTS OF BOTH SYSTEMS ARE VERY SIMILAR, IMPACTS ON STATISTICAL GUIDANCE FOR BOTH GLOBAL AND REGIONAL SYSTEMS ARE VERY SMALL, AND THEREFORE THERE IS VERY LITTLE IMPACT ON SCRIBE. EVERELL / ADMA / SMA-SMC TORONTO