GIDS-1 WSI NOWrad Imagery
     
     
     1.0  General Description
     
          The WSI Corporation NOWrad product radar reflectivity composite
     imagery is one of several image datasets provided as part of the GEWEX
     Continental-scale International Project (GCIP) Initial Dataset One (GIDS-
     1). The NOWrad imagery covers a sector (approx 6 deg latitude by 12 deg
     longitude box) over the Central United States.  The NOWrad sector was
     generally fixed over the STORM-FEST domain but moved slightly
     depending upon areas of active weather. The NOWrad imagery contains
     daily composites valid 1200 UTC (whenever available) for the first half
     of the GIDS-1 time period (01 February 1992 through 15 March 1992).  
     
     2.0  Detailed Data Description
     
          WSI Corporation routinely ingested radar information from
     operational National Weather Service radars in the United States.  From
     this information, WSI produced national "NOWrad" imagery every 15
     minutes which was composited from simultaneous reflectivity images of
     multiple radars.  WSI performed "real-time" ground clutter suppression on
     the data during the compositing procedure to remove false reflectivity
     patterns.  Once the national composite processing was completed, both the
     national composite (8 km resolution) and high resolution regional imagery
     (2 km resolution) were available for transmission to WSI clients.  The
     National Severe Storms Forecast Center (NSSFC) in Kansas City, MO,
     received and reformatted the high resolution regional data into their
     McIDAS system.  NSSFC used six "floating" sectors which were routinely
     geographically moved depending upon severe weather location.  During the
     STORM-FEST experiment, NSSFC fixed one of these sectors over the
     STORM-FEST domain. 
     
          The NOWrad imagery was collected every 15 minutes during the
     STORM-FEST period (01 February 1992 through 15 March 1992) and
     archived in PC-McIDAS format.  From this dataset a representative daily
     image was selected at 1200 UTC whenever possible, to coincide with the
     National Meteorological and Climate Analysis Center's Daily Weather
     Map Series imagery (1200 UTC) and GOES-7 Infrared image.  The selected
     daily images were translated to Graphical Interchange Format (GIF).
     These images were mapped and color enhanced using the standard
     WSR-88D (formerly NEXRAD) reflectivity breakpoints. 
     
          These GIF images can be viewed using any standard GIF display
     software package. However, any additional detailed information from the
     original files (i.e., pixel reflectivity values, navigation, etc.) are not
     retrievable from the GIF image, but can be obtained from the actual data
     available from the UCAR Office of Field Project Support (OFPS). Further
     general information on GIF files, structure and format are provided in
     the References.
     
     2.1  Data Remarks
     
          All daily images are valid for 1200 UTC.  Imagery were unavailable
     for three days during the first half of the GIDS-1 period: 
     February 1, 4, and 5, 1992. 
     
     3.0  Quality Control Processing
     
          No additional quality control or re-navigation was performed on
     the imagery by the UCAR/OFPS. OFPS did overlay the map and enhance the
     imagery before conversion to GIF files.
     
     4.0  References
     
     Kay: Graphics File Formats, 2/E.  ISBN: 0-07-034025-0, McGraw Hill.
     
     Luse, M: Bitmapped Graphics Programming in C++. ISBN: 0-201-
          63209-8, Addison-Wesley.