r.stage3(1)		      Grass User's Manual		   r.stage3(1)



NNAAMMEE
       rr..ssttaaggee33 - NEXRAD weather radar input tool.

       _(_G_R_A_S_S _R_a_s_t_e_r _P_r_o_g_r_a_m_)

GGRRAASSSS VVEERRSSIIOONN
       4.x

SSYYNNOOPPSSIISS
       rr..ssttaaggee33 [--vv] iinnppuutt==_n_a_m_e [oouuttppuutt==_n_a_m_e]

DDEESSCCRRIIPPTTIIOONN
       A  Stage III precipitation product is a mosaic of all the Stage II pre-
       cipitation estimates within the RFC (River Forecast Center) area.   The
       Stage  III  products  are produced by merging radar precipitation esti-
       mates (Stage I) with ground truth data provided by rain gages.  In  the
       Arkansas-red River Forecast Center (ABRFC) this includes 15 88-D radars
       and approximately 500 rain gages.   The	13  RFC's  within  the	United
       States  will  eventually  produce  Stage  III products.	As of 4-94 the
       ABRFC is the only RFC currently producing Stage III products.  As  more
       radars  come  on  line other RFC's will begin producing this product as
       well.  The 88-D radars have difficulty detecting precipitation when the
       raindrops  are  very  small or when the precipitation is in the form of
       snow.  Under these conditions precipitation estimates tend to be  under
       estimated.  Large Hail within a storm causes the radar to over estimate
       precipitation amounts.  The grid cell size is approximately 4 km  by  4
       km.   The NetCDF files containing the precipitation values in the units
       of 1/100 of mm can be obtained from ABRFC's  gopher  server.   _r_._s_t_a_g_e_3
       program generates the GRASS raster map layers only in the Lat/Lon coor-
       dinate system.  UTM is not utilized because the area  being  referenced
       is  too large for a UTM zone.  The region settings for the ABRFC's cov-
       erage area is:

	__________________________________________
	projection: 3 (Latitude-Longitude)
	zone:  0
	north: 41:16:06N
	south: 32:48:28N
	east:  90:53:28W
	west:  107:08:03W
	__________________________________________


       You may use the clark66 spheroid and use any  resolution  that  may  be
       suitable  as  far as your other data requirements are concerned. (start
       with esres= nsres = 0:00:30).


       This version of _r_._s_t_a_g_e_3 will work only on NetCDF files	created  after
       the 6th of April 1994.


       You  will need the NetCDF libraries created by the Unidata Program Cen-
       ter.  The NetCDF libraries can  be  obtained  via  anonymous  ftp  from
       unidata.ucar.edu  under	pub/netcdf/netcdf.tar.Z.  You will the need to
       compile	the  libraries.   _r_._s_t_a_g_e_3  can  be  only  run	within	GRASS.
       _r_._s_t_a_g_e_3  needs	both  the  NetCDF  libraries  as  well	as  the  GRASS
       libraries.  If you have all the libraries then _r_._s_t_a_g_e_3 can be compiled
       simply by running "gmake" (For GRASS 4.2 it is gmake4.2) in this direc-
       tory.


       In the above, if the output parameter is not specified then  a  mapname
       with  the  same	name  as  that of the input parameter is created.  The
       rainbow colortable is created for the  resultant  map.	The  resulting
       maps have a resolution of 0:02:59.


       A  few sample NetCDF files and the corresponding GIF files are provided
       in the sample directory.  The  vector  directory  contains  the	vector
       boundary output from the command _v_._o_u_t_._a_s_c_i_i of the ABRFC basin.


       To  run	_r_._s_t_a_g_e_3 on the sample files just go into the sample directory
       and type:


       _r_._s_t_a_g_e_3 _-_v _i_n_=_0_4_0_5_9_4_1_8_._n_c


       This will create a raster  map  by  the	name  04059418.nc.   Similarly
       _r_._s_t_a_g_e_3  can be run on other sample files. You can use the correspond-
       ing GIF files to compare them.  Since the GIF files are in a  different
       projection  system, there is some distortion in between the raster maps
       and the GIF file.  However the values in the raster are	properly  geo-
       referenced.

   OOPPTTIIOONNSS
   FFllaagg::
       --vv     Verbose


   PPaarraammeetteerrss::
       iinnppuutt == nnaammee
	      Name of the netcdf file to be converted.

       oouuttppuutt == nnaammee
	      Name of the resultant raster map.


AAUUTTHHOORRSS
       Nalneesh Gaur, Arkansas Red Basin River Forecast Center

       Norman L. Bingham, Arkansas Red Basin River Forecast Center

       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_2_/_0_1_/_2_5 _0_5_:_4_5_:_3_4 _$



GRASS 5.0							   r.stage3(1)
