two time dimension

Hello
I am trying to plot the output of the WRF model .
before using the NCL, i write small script to just cut the variables that
I would plot like MSLP,TEMP
I found that when I write ncl_filedump for the file that i got , i found
that there is two time although there is just
one time dimension . and after I convert the file into grib2 using the
cnvgrib , I found that the second dimension disappear .
the output of the ncl_filedump for the grib1 file is
 dimensions:
      forecast_time0 = 256
      lv_ISBL1 = 6
      g0_lat_2 = 61
      g0_lon_3 = 145
      forecast_time4 = 417
   variables:
      float TMP_GDS0_ISBL ( forecast_time0, lv_ISBL1, g0_lat_2, g0_lon_3 )
         center : US National Weather Service - NCEP (WMC)
         long_name : Temperature
         units : K
         _FillValue : 1e+20
         level_indicator : 100
         gds_grid_type : 0
          parameter_table_version : 2
         parameter_number : 11
         model : North Pacific Hurricane Wave Model
         initial_time : 11/02/2010 (00:00)

      float TMP_GDS0_ISBL_10 ( forecast_time4, lv_ISBL1, g0_lat_2, g0_lon_3
)
         center : US National Weather Service - NCEP (WMC)
         long_name : Temperature
         units : K
         _FillValue : 1e+20
         level_indicator : 100
         gds_grid_type : 0
          parameter_table_version : 2
         parameter_number : 11
         model : North Pacific Hurricane Wave Model
         initial_time : 11/02/2010 (00:00)

      float R_H_GDS0_ISBL ( forecast_time0, lv_ISBL1, g0_lat_2, g0_lon_3 )
         center : US National Weather Service - NCEP (WMC)
         long_name : Relative humidity
         units : %
          _FillValue : 1e+20
         level_indicator : 100
         gds_grid_type : 0
         parameter_table_version : 2
         parameter_number : 52
         model : North Pacific Hurricane Wave Model
         initial_time : 11/02/2010 (00:00)

      float R_H_GDS0_ISBL_10 ( forecast_time4, lv_ISBL1, g0_lat_2, g0_lon_3
)
         center : US National Weather Service - NCEP (WMC)
         long_name : Relative humidity
         units : %
         _FillValue : 1e+20
         level_indicator : 100
         gds_grid_type : 0
         parameter_table_version : 2
         parameter_number : 52
         model : North Pacific Hurricane Wave Model
         initial_time : 11/02/2010 (00:00)

      integer forecast_time4 ( forecast_time4 )
         long_name : Forecast offset from initial time
         units : hours

      float g0_lat_2 ( g0_lat_2 )
         long_name : latitude
         GridType : Cylindrical Equidistant Projection Grid
         units : degrees_north
         Dj : 0.33
         Di : 0.33
         Lo2 : 52.917
         La2 : 37.372
         Lo1 : 5.397
         La1 : 17.572

      float g0_lon_3 ( g0_lon_3 )
         long_name : longitude
         GridType : Cylindrical Equidistant Projection Grid
         units : degrees_east
         Dj : 0.33
         Di : 0.33
         Lo2 : 52.917
         La2 : 37.372
         Lo1 : 5.397
         La1 : 17.572

      integer lv_ISBL1 ( lv_ISBL1 )
         long_name : isobaric level
         units : hPa

      integer forecast_time0 ( forecast_time0 )
         long_name : Forecast offset from initial time
         units : hours

and after i convert the file from grib1 to grib2 (cnvgrib -g12 file_grib1
file_grib2), i found that the second time disappear and it became part of
the first time .
dimensions:
      forecast_time0 = 673
      lv_ISBL0 = 6
      lat_0 = 61
      lon_0 = 145
   variables:
      float TMP_P0_L100_GLL0 ( forecast_time0, lv_ISBL0, lat_0, lon_0 )
         center : US National Weather Service - NCEP (WMC)
         production_status : Operational products
         long_name : Temperature
         units : K
         _FillValue : 1e+20
         grid_type : Latitude/longitude
         parameter_discipline_and_category : Meteorological products,
Temperature
         parameter_template_discipline_category_number : ( 0, 0, 0, 0 )
         level_type : Isobaric surface (Pa)
         initial_time : 11/02/2010 (00:00)

      float RH_P0_L100_GLL0 ( forecast_time0, lv_ISBL0, lat_0, lon_0 )
         center : US National Weather Service - NCEP (WMC)
         production_status : Operational products
         long_name : Relative humidity
         units : %
         _FillValue : 1e+20
         grid_type : Latitude/longitude
         parameter_discipline_and_category : Meteorological products,
Moisture
         parameter_template_discipline_category_number : ( 0, 0, 1, 1 )
         level_type : Isobaric surface (Pa)
         initial_time : 11/02/2010 (00:00)

      float lat_0 ( lat_0 )
         long_name : latitude
         grid_type : Latitude/Longitude
         units : degrees_north
         Dj : 0.33
         Di : 0.33
         Lo2 : 52.917
         La2 : 37.372
         Lo1 : 5.397
         La1 : 17.572

      float lon_0 ( lon_0 )
         long_name : longitude
         grid_type : Latitude/Longitude
         units : degrees_east
         Dj : 0.33
         Di : 0.33
         Lo2 : 52.917
         La2 : 37.372
         Lo1 : 5.397
         La1 : 17.572

      float lv_ISBL0 ( lv_ISBL0 )
         long_name : Isobaric surface
         units : Pa

      integer forecast_time0 ( forecast_time0 )
         long_name : Forecast offset from initial time
         units : hours

I don't know if my problem is with the NCL or with dealing with grib1 and
grib2 .
Have i to convert the files from grib1 to grib2 to see just one
time dimension.
I contacted the WRF help , and they advise me to contact the NCL support
for this , and they told me that my file is ok.
thanks in advance

-- 
===============
Ahmed Lasheen
Junior researcher at Cairo Numerical Weather Prediction Center (CNWPC)
Egyptian Meteorological Authority(EMA)
Cairo,Egypt
===============

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Received on Fri Jun 22 14:41:07 2012