February 9, 1998

MEMORANDUM TO:  Record
FROM:           Dennis A. Keyser -- W/NMC22
Subject:        Changes to 3DVAR/OI/SSI-Data Preprocessor
                (May 1, 1997 Version --
                 R3DV DATACARD UPDATE # 7.3)

Implemented 12Z 09 February 1998:

CHANGES IN DATA PROCESSING WITH THE IMPLEMENTATION OF THE 3DVAR
ANALYSIS AT 12Z ON 09 FEBRUARY 1998 (VS. PREVIOUS OI VERSION)


All below are PREPDATA CARD CHANGES (except where noted) ---

	1. The data selection region is now a subset of the
           Northern Hemisphere (OI is entire Northern Hemisphere).

	2. Upper-air data types no longer interpolate data to
           special (auxiliary) 25/50 mb levels.

	3. For upper-air data types, T,Z, wind, moisture are no
           longer interpolated to levels where they are missing.

	4. Block 42 and 43 RAOB mass reports are no longer
           automatically purged.

	5. The following data types are now assimilated:
		a. VAD (NEXRAD) winds.
		b. NESDIS high-density imager water vapor cloud top
                   satellite winds.
		c. ACARS aircraft temperature (mass) reports.
		d. Conventional AIREP/PIREP and AMDAR/ASDAR
                   aircraft temperature (mass) reports (PREPACQC
                   data card change).
		e. Flight-level, single-level Reconnaissance
                   temperature (mass) reports. 
		f. Surface wind reports over land.
		g. Surface land mass and wind reports within the
                   old LFM grid domain and with missing station
                   pressure and mean sea-level pressure.  NOTE: If
                   altimeter setting is available, it is used as an
                   estimate of the sea-level pressure.  Otherwise,
                   the standard atmosphere value of 1013 mb is
                   used.  The station pressure is then generated
                   from this, giving the report a type 183 (mass)
                   or 284 (wind).
		h. SSM/I superobed wind speed (operational
                   Goodberlet algorithm). 

	6. The following data types have time window changes:
		a. GOES PW retrievals now +/-1.5 hours (was +/- 0.5
                   hours).
		b. Surface land reports now +/- 1.5 hours (was +/-
                   0.5 hours).

	7. The following profile data types are now processed to a
           higher level:
		a. TOVS soundings now processed at levels above
                   10mb (before stopped at 10 mb).
		b. RAOB, PIBAL, RECCO, PROFILER, VADWIND reports
                   now processed up to 1 mb for mandatory level
                   data (before stopped at 10 mb), and up to 1 mb
                   for significant level data (before stopped at 50
                   mb).
		c. RAOB, RECCO moisture now processed up to 1 mb
                   (before stopped at 250 mb).

	8. TOVS soundings are now unpacked in the 40-level format
           at the full 80 km resolution.  Before, they were
           unpacked in the 15-layer NMCEDS format at 250 km
           resolution.

	9. The mass report level for an observation will now be
           processed if the temperature is valid but the height is
           either missing or bad.

       10. CLASS soundings will NOT be processed.  These data are
           no longer available anyway.

       11. Conventional aircraft reports are no longer superobed
           (PREPACQC data card change).

       12. Conventional AIREP/PIREP reports over CONUS are
           processed, but they are flagged for non-use by the
           analysis. Before, they were not processed.