[gradsusr] OMI SO2 HDF5

[James E. Johnson]

First, make sure you have a version of GrADS that supports reading HDF-EOS5 grid files (2.0.a7 or higher).
Below is a sample GrADS control (.ctl) file that will let you read an OMI SO2 level-3 gridded HDF-EOS5 data file:

DSET  OMI-Aura_L3-OMSO2e_2004m1001_v003-2011m0526t144250.he5
DTYPE hdf5_grid
TITLE OMI Level-3 Daily Lat/Lon 0.25deg Gridded Column Sulfur Dioxide Version 003 (OMSO2e.003)
UNDEF -1.26765060e+30 _FillValue
XDEF  1440 linear -180.0 0.25
YDEF   720 linear  -90.0 0.25
ZDEF     1 levels 1
TDEF     1 linear 01oct2004 1dy
VARS    14
/HDFEOS/GRIDS/OMI~Total~Column~Amount~SO2/Data~Fields/ColumnAmountSO2_PBL=>so2pbl     0  y,x  Vertical Column Amount SO2 
(Planetary Boundary Layer)
/HDFEOS/GRIDS/OMI~Total~Column~Amount~SO2/Data~Fields/SlantColumnAmountSO2=>slantso2  0  y,x  Slant Column Amount SO2
/HDFEOS/GRIDS/OMI~Total~Column~Amount~SO2/Data~Fields/Latitude=>lat                   0  y,x  Geodetic Latitude
/HDFEOS/GRIDS/OMI~Total~Column~Amount~SO2/Data~Fields/Longitude=>lon                  0  y,x  Geodetic Longitude
/HDFEOS/GRIDS/OMI~Total~Column~Amount~SO2/Data~Fields/Time=>tai93                     0  y,x  Time (seconds since January 1, 1993)
/HDFEOS/GRIDS/OMI~Total~Column~Amount~SO2/Data~Fields/OrbitNumber=>orbit              0  y,x  Orbit Number
/HDFEOS/GRIDS/OMI~Total~Column~Amount~SO2/Data~Fields/LineNumber=>line                0  y,x  Line Number
/HDFEOS/GRIDS/OMI~Total~Column~Amount~SO2/Data~Fields/SceneNumber=>scene              0  y,x  Scene Number
/HDFEOS/GRIDS/OMI~Total~Column~Amount~SO2/Data~Fields/ColumnAmountO3=>to3             0  y,x  Total Column Amount O3
/HDFEOS/GRIDS/OMI~Total~Column~Amount~SO2/Data~Fields/RadiativeCloudFraction=>rcf     0  y,x  Radiative Cloud Fraction
/HDFEOS/GRIDS/OMI~Total~Column~Amount~SO2/Data~Fields/TerrainHeight=>theight          0  y,x  Terrain Height
/HDFEOS/GRIDS/OMI~Total~Column~Amount~SO2/Data~Fields/SolarZenithAngle=>sza           0  y,x  Solar Zenith Angle
/HDFEOS/GRIDS/OMI~Total~Column~Amount~SO2/Data~Fields/RelativeAzimuthAngle=>raa       0  y,x  Relative Azimuth Angle
/HDFEOS/GRIDS/OMI~Total~Column~Amount~SO2/Data~Fields/ViewingZenithAngle=>vza         0  y,x  Viewing Zenith Angle
ENDVARS


Note the group paths to the data field variables must be specified in full, and any spaces converted to tilda (~) characters.

You can rename the OMSO2e data files by removing the production date/time from the version (stuff after v003), then you would have 
a file name like OMI-Aura_L3-OMSO2e_2004m1001_v003.he5. With this you could modify the DSET (and add OPTIONS) to the .ctl file

DSET  ^OMI-Aura_L3-OMSO2e_%ym%m%d_v003.he5
OPTIONS template

and then you could read in multiple files for a range of dates (remember to also adjust the TDEF range).

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| James E. Johnson                      | address:                           |
| Wyle Information Systems, Inc.        |  NASA Goddard Space Flight Center  |
| e-mail: james.johnson at nasa.gov        |  Distributed Active Archive Center |
| phone:  301-614-5121                  |  Code 610.2, Bldg 32, Room S130G   |
| fax:    301-614-5268                  |  Greenbelt, MD  20771              |
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