[gradsusr] MODIS AEROSOL PRODUCTS

[Yaqiang Wang]

The nc data files have no time dimension, so you need to add unlimited time
dimension to each file firstly.


On Wed, May 29, 2013 at 8:08 PM, Joshua Ngaina <jngaina at gmail.com> wrote:

>
> *Dear All,
>
> *
> *I have daily MODIS aerosol products (Small mode fraction).
>
> *
> *I wanted to merge these files using CDO but it seemed the files were not
> merged.  *
>
> met at met-HP-Compaq-6000-Pro-MT-PC:/media/BERTH/MODIS_DAILY$ cdo mergetime
> *.nc ALLMOD08.nc
> cdo mergetime: Processed 4147200 values from 64 variables over 32
> timesteps. ( 0.18s )
> *
> So to check one of the files, I used grads and I got this error: DF file
> has no discernable time coordinate -- using default values*.
>
> ga-> sdfopen
> MOD08_D3.A2001001.051.2010286151047.pscs_000500504418.Optical_Depth_Ratio_Small_Land_And_Ocean_Mean.G3.nc
> Scanning self-describing file:
> MOD08_D3.A2001001.051.2010286151047.pscs_000500504418.Optical_Depth_Ratio_Small_Land_And_Ocean_Mean.G3.nc
> SDF file has no discernable time coordinate -- using default values.
> SDF file
> MOD08_D3.A2001001.051.2010286151047.pscs_000500504418.Optical_Depth_Ratio_Small_Land_And_Ocean_Mean.G3.ncis open as file 1
> LON set to 0 360
> LAT set to -89.5 89.5
> LEV set to 0 0
> Time values set: 1:1:1:0 1:1:1:0
> E set to 1 1
> ga-> q file
> File 1 :
>   Descriptor:
> MOD08_D3.A2001001.051.2010286151047.pscs_000500504418.Optical_Depth_Ratio_Small_Land_And_Ocean_Mean.G3.nc
>   Binary:
> MOD08_D3.A2001001.051.2010286151047.pscs_000500504418.Optical_Depth_Ratio_Small_Land_And_Ocean_Mean.G3.nc
>   Type = Gridded
>   Xsize = 360  Ysize = 180  Zsize = 1  Tsize = 1  Esize = 1
>   Number of Variables = 2
>      optical_depth_l  0  y,x  Aerosol Optical Thickness at 0.55 microns
> for both Ocean (best) and Land (corrected): Mean
>      optical_depth_r  0  y,x  Ratio of small mode aerosol optical depth at
> 0.55 micron for both land and ocean: Mean
> *
> *
> *I also checked the merged netcdf file *
>
> ga-> sdfopen ALLMOD08.nc
> Scanning self-describing file:  ALLMOD08.nc
> SDF file has no discernable time coordinate -- using default values.
> SDF file ALLMOD08.nc is open as file 1
> LON set to 0 360
> LAT set to -89.5 89.5
> LEV set to 0 0
> Time values set: 1:1:1:0 1:1:1:0
> E set to 1 1
> ga-> q file
> File 1 :
>   Descriptor: ALLMOD08.nc
>   Binary: ALLMOD08.nc
>   Type = Gridded
>   Xsize = 360  Ysize = 180  Zsize = 1  Tsize = 1  Esize = 1
>   Number of Variables = 2
>      optical_depth_l  0  y,x  Aerosol Optical Thickness at 0.55 microns
> for both Ocean (best) and Land (corrected): Mean
>      optical_depth_r  0  y,x  Ratio of small mode aerosol optical depth at
> 0.55 micron for both land and ocean: Mean
>
> *I also noted that the dimension of both files were the same.
>
> *
> *My major problem is with many files of this type, How do I merge this
> files for analysis with GrADs. Please advise
> *
> *
> *
> *
> Regards and Thanks,*
>
> Joshua Ngaina
>
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>
>


-- 
*************************************************
Dr. Yaqiang Wang
Chinese Academy of Meteorological Sciences (CAMS)
46, Zhong-Guan-Cun South Avenue
Beijing, 100081
China

yaqiang.wang at gmail.com

http://www.meteothinker.com
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