[NARCCAP-discuss] coordinate systems for NARCCAP model grids

[Seth McGinnis]

Hi Shuang-Ye,

The grid_mapping attribute of the main data variable in each file names a
"dummy" variable whose attributes record the type and parameters of the map
projection used by each RCM.  Here's a summary all in one place:

CRCM
  polar_stereographic:grid_mapping_name = "polar_stereographic"
  polar_stereographic:latitude_of_projection_origin = 90.
  polar_stereographic:standard_parallel = 60.
  polar_stereographic:straight_vertical_longitude_from_pole = 263.
  polar_stereographic:false_easting = 3450000.
  polar_stereographic:false_northing = 7450000.

ECP2
  polar_stereographic:grid_mapping_name = "polar_stereographic"
  polar_stereographic:latitude_of_projection_origin = 90.
  polar_stereographic:standard_parallel = 60.
  polar_stereographic:straight_vertical_longitude_from_pole = 263.
  polar_stereographic:false_easting = 4700000.
  polar_stereographic:false_northing = 8400000.

HRM3
  rotated_pole:grid_mapping_name = "rotated_latitude_longitude"
  rotated_pole:grid_north_pole_latitude = 42.5
  rotated_pole:grid_north_pole_longitude = 83.

MM5I
  Lambert_Conformal:grid_mapping_name = "lambert_conformal_conic"
  Lambert_Conformal:latitude_of_projection_origin = 47.5
  Lambert_Conformal:longitude_of_central_meridian = -97.
  Lambert_Conformal:standard_parallel = 30., 60.
  Lambert_Conformal:false_easting = 3825000.
  Lambert_Conformal:false_northing = 3200000.

RCM3
  Transverse_Mercator:grid_mapping_name = "transverse_mercator"
  Transverse_Mercator:latitude_of_projection_origin = 47.5
  Transverse_Mercator:longitude_of_central_meridian = -97.
  Transverse_Mercator:scale_factor_at_central_meridian = 1.
  Transverse_Mercator:false_easting = 3925000.
  Transverse_Mercator:false_northing = 3175000.

WRFG
  Lambert_Conformal:grid_mapping_name = "lambert_conformal_conic"
  Lambert_Conformal:latitude_of_projection_origin = 47.5
  Lambert_Conformal:longitude_of_central_meridian = -97.
  Lambert_Conformal:standard_parallel = 30., 60.
  Lambert_Conformal:false_easting = 3325000.
  Lambert_Conformal:false_northing = 2700000.

The timeslice data has no projection; both models are on rectilinear lat-lon
grids.

Cheers,

--Seth

>Hi,
>
>Would you mind providing me with some information on the coordinate systems
>used for xc and yc values for each of the NARCCAP model grids?
>
>Thanks a lot.
>
>Shuang-Ye