#  Temporary documentation file, dataset mm_default_rt

This dataset contains the default soilwater volumetric percent for three
layer depths over the 36 km mesoscale model realtime domain, using mean
climatological data for summer and winter.  For each season, there are
two sets of files:  one set uses soil textures derived by lookup table
from the USGS/EDC 1-km landcover data set; the other set uses the
dominant surface soil textures derived from the USDA/NRCS STATSGO soils
database for the U.S.

The spatial extent of the realtime domain covers most of the 48
conterminous U.S. and adjacent portions of Canada, Mexico, and the
Atlantic Ocean.  The western boundary excludes parts of Washington,
Oregon, and Nevada, and most of California.

The horizontal spatial resolution is 36 km;  the realtime domain is
represented by a 94 row by 114 column array of 36-km square grid cells.

The three soil layers are defined as follows:

  Layer 1:  Top 10 cm of soil.
  Layer 2:  From soil surface to bottom of root zone, as defined for
	    BATS classes; this depth is class dependent.
  Layer 3:  Top 10 m of soil.

Note that the model assumes that the same soil texture extends from the
surface to 10 meters depth, that a given texture extends over an
entire 36-km grid cell, and that neither bedrock nor the water table is
encountered.

The four sets of files are identified as follows:

  edc_summer.*	    Summer soil water, soil texture from EDC landcover.
  edc_winter.*	    Winter soil water, soil texture from EDC landcover.
  statsgo_summer.*  Summer soil water, soil texture from STATSGO.
  statsgo_winter.*  Winter soil water, soil texture from STATSGO.

The data are in a nonstandard Lambert conformal conic projection (LAS
projection code mml_4193).  Parameters are 

	Projection units:	meters
	Spheroid:		sphere of radius 6,370,000 meters
	1st standard parallel:	30 deg N
	2nd standard parallel:	60 deg N
	Central meridian:	-93 deg (W)
	Latitude of origin:	41 deg N