Source:  NASA/Goddard
Creation date:  2001
Range of data:  Sep 11, 1999 06Z to Dec 31, 1999 18Z
Data Format:  Flat binary, Big_endian (Grads readable)
First point on grid:  Prime Meridian (stored west to east) and South Pole
Size of dataset:  250GB
Resolution:  576 longitude points (.625 deg)
             361 latitude points  (.500 deg)
             35 pressure levels
             6 hour interval
Levels:
 1000.0000  996.0000  988.0000  979.0000  969.0000  958.0000
  947.0000  935.0000  922.0000  894.0000  850.0000  830.0000
  800.0000  750.0000  700.0000  650.0000  600.0000  550.0000
  500.0000  450.0000  400.0000  350.0000  300.0000  250.0000
  200.0000  150.0000  100.0000   70.0000   50.0000   30.0000
   10.0000    5.0000    2.0000    1.0000    0.4000

Quantities:
  Surface
    Surface geopotential (g*m)
    Sea-level pressure (hPa)
    Surface pressure (Pascal)
    Instant precip (mm/day)
    Vertically-integrated, random overlap, high cloud amount [fraction]
    Vertically-integrated, random overlap, low cloud amount [fraction]
    Vertically-integrated, random overlap, mid cloud amount [fraction]
    Vertically-integrated, random overlap, total cloud cover [fraction]
    Surface type flag [flag]
    Planetary boundary layer height [m]
    Convective precipitation rate [mm/day]
    Large-scale precipitation rate [mm/day]
    2 meter specific humidity [Kg/Kg]
    Surface pressure [Pa]
    2 meter temperature [K]
    Ground temperature [K]
    10 meter U wind [m/s]
    2 meter U wind [m/s]
    10 meter V wind [m/s]
    2 meter V wind [m/s]
  Upper Air
    Geopotential height (m)
    U-wind (m/s)
    V-wind (m/s)
    Temperature (K)
    Specific humidity (g/g)
    Vertical velocity (Pa/s)
    Actual cloud liquid water path length [gram/m**2]
    Cloud fraction [fraction]
    Effective cloud fraction [fraction]
    Eddy diffusivity for momentum [m**2/s]

Comments:
  This is the first nature run to be generated in late summer and extend
  across seasons.  It is also first nature run to possess tropical cyclones.  
  It has a slightly higher horizontal and vertical resolution than T213
  nature run.

  During the nature run calibration/validation (CalVal) process, it was
  determined that the gravity wave drag parameter was improperly set for
  a long integration.  As a result, the last two months were rejected,
  leaving only about 50 days.  Nevertheless, this is still the longest
  nature run used for research purposes prior to 2007.

  The conventional observations generated from this nature run 
  are available in NCEP BUFR format.