960423: NWW-NOUS (fwd)

 
TO        NWS OFFICES...FAMILY OF SERVICES SUBSCRIBERS...NOAA
          WEATHER WIRE SUBSCRIBERS...NWS CUSTOMERS AND OTHER NWS
          PRODUCT USERS
 
FROM      RICHARD LANE...FORECAST SYSTEMS AND TECHNOLOGY 
 
 
SUBJECT   AUTOMATED WSR-88D RADAR OBSERVATION (ROB) ENHANCEMENTS
 
 
THE AVIATION WEATHER CENTER (AWC), AVIATION SUPPORT BRANCH (ASB)
OF THE NATIONAL WEATHER SERVICE (NWS) PRODUCES RADAR OBSERVATIONS
(ROBS), COMMONLY REFERRED TO AS AUTOROBS (ALSO REFERRED TO AS SDS
BY SOME) FOR COMMISSIONED WSR-88DS (NEXRAD).  A NEW STEP HAS BEEN
ADDED TO THEIR PROCESS (ALGORITHM) IN ORDER TO IMPROVE THE
QUALITY OF THE WSR-88D ROBS.  THIS NEW STEP IS DESIGNED TO
ELIMINATE A GREATER AMOUNT OF FALSE RADAR SIGNALS (RETURNS) THAN
THE PROCESS WAS PREVIOUSLY CAPABLE OF DOING.  DEVELOPMENT WORK
FOR THIS NEW PROCESS WAS COMPLETED IN EARLY DECEMBER 1995, AND
WAS TESTED FROM MID-DECEMBER 1995 THROUGH EARLY APRIL 1996. 
RESULTS HAVE SHOWN AN IMPROVEMENT IN REDUCING GROUND CLUTTER AND
ANOMALOUS PROPAGATION (AP).  THE NEW PROCESS WAS PUT INTO
OPERATIONAL USE FOR GENERATION OF THE ROBS, MONDAY, APRIL 22,
1996.
 
FOLLOWING IS BACKGROUND INFORMATION ON THE PRODUCTION OF WSR-88D
ROBS -
 
THE WSR-88D AUTOMATICALLY GENERATES A PRODUCT CALLED THE RADAR
CODED MESSAGE (RCM).  THE RCM CURRENTLY IS BASED ON THE COMPOSITE
REFLECTIVITY, WHICH IS THE MAXIMUM RETURN WITHIN THE DIGITIZING
AREA.  THE RCM CONTAINS CONSIDERABLE FALSE ECHOES, AND NEEDS TO
BE EDITED.  THE RCMS ARE SENT FROM EACH WSR-88D TO THE AWC,
FORMERLY THE NATIONAL SEVERE STORMS FORECAST CENTER (NSSFC), IN
KANSAS CITY, MISSOURI VIA THE NWS AUTOMATION OF FIELD OPERATIONS
AND SERVICES (AFOS) COMMUNICATIONS SYSTEM.  THE ASB USES
SOPHISTICATED COMPUTER EDITING PROGRAM TO ELIMINATE FALSE ECHOES
BY COMPARING EVERY ECHO WITH CONFIRMING METEOROLOGICAL DATA SETS,
SUCH AS SATELLITE DATA, MODEL DATA, OVERLAPPING RADAR DATA, AND
LIGHTNING DATA.  THE NEW STEP IN THE EDITING HAS BEEN TO CHECK
THE RCM ECHO WITH THE NEW HOURLY DIGITAL PRECIPITATION  (HDP)
PRODUCT DEVELOPED BY THE OFFICE OF HYDROLOGY.  THIS NEW HDP HAS
SUPERIOR FALSE ECHO REJECTION, AND TEST RESULTS HAVE DEMONSTRATED
A NOTICEABLE IMPROVEMENT OF THE ROB PRODUCTS IN ELIMINATING FALSE
ECHOES.  FOR EACH COMMISSIONED WSR-88D SITE , THE ROBS ARE
GENERATED FROM THE EDITED DATA SET WITH AUTO APPENDED AS THE LAST
ENTRY IN THE REMARKS SECTION OF THE STORM DETECTION PORTION OF
THE OBSERVATION (REPORT).  THE ROBS ARE SENT TO THE NWS
TELECOMMUNICATION GATEWAY IN SILVER SPRING, MARYLAND AND THEN
DISTRIBUTED TO ALL USERS.
 
IF YOU HAVE ANY QUESTIONS, CALL RICH LANE, (301) 713-1867, EXT
137.
 
END