Example CF-NetCDF for Satellite

Back to WCS Access to netCDF Files

A Real life example how to download and store satellite data.

Total Ozone Mapping Spectrometer (TOMS) satellite

This data has been collected by three different satellites from 1979 to present. It is downloadable in text files, linear rectangular 288 * 180 grid.

Nimbus satellite data First 1978-11-01 Last 1993-05-06

1. first nimbus data
2. last nimbus data ftp://toms.gsfc.nasa.gov/pub/nimbus7/data/aerosol/Y1993/L3_aersl_n7t_19930506.txt

template_path_nimbus = "/pub/nimbus7/data/aerosol/Y%Y/L3_aersl_n7t_%Y%m%d.txt" first_nimbus_datetime = datetime.datetime(1979, 1, 3) last_nimbus_datetime = datetime.datetime(1993, 5, 6)

1. last eptoms data ftp://toms.gsfc.nasa.gov/pub/eptoms/data/aerosol/Y2005/L3_aersl_ept_20051231.txt

template_path_eptoms = "/pub/eptoms/data/aerosol/Y%Y/L3_aersl_ept_%Y%m%d.txt" first_eptoms_datetime = datetime.datetime(1996, 7, 25)

1. ftp://toms.gsfc.nasa.gov/pub/omi/data/aerosol/Y2004/L3_aersl_omi_20040906.txt

template_path_omi = "/pub/omi/data/aerosol/Y%Y/L3_aersl_omi_%Y%m%d.txt" first_omi_datetime = datetime.datetime(2004, 9, 6)

ftp, url templates, file format

Creating Empty CF-NetCDF File

NCML

   <netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2">
       <explicit />
       <attribute name="title" type="string" value="NASA TOMS Project" />
       <attribute name="comment" type="string" value="NASA Total Ozone Mapping Spectrometer Project" />
       <attribute name="Conventions" type="string" value="CF-1.0" />
       <dimension name="time" length="0" isUnlimited="true" />
       <dimension name="lat" length="180" />
       <dimension name="lon" length="288" />
       <variable name="time" type="int" shape="time">
           <attribute name="standard_name" type="string" value="time" />
           <attribute name="long_name" type="string" value="time" />
           <attribute name="units" type="string" value="days since 1979-01-01" />
           <attribute name="axis" type="string" value="T" />
       </variable>
       <variable name="lat" type="double" shape="lat">
           <attribute name="standard_name" type="string" value="latitude" />
           <attribute name="long_name" type="string" value="latitude" />
           <attribute name="units" type="string" value="degrees_north" />
           <attribute name="axis" type="string" value="Y" />
           <values start="-89.5" increment="1" />
       </variable>
       <variable name="lon" type="double" shape="lon">
           <attribute name="standard_name" type="string" value="longitude" />
           <attribute name="long_name" type="string" value="longitude" />
           <attribute name="units" type="string" value="degrees_east" />
           <attribute name="axis" type="string" value="X" />
           <values start="-179.375" increment="1.25" />
       </variable>
       <variable name="AI" type="float" shape="time lat lon">
           <attribute name="long_name" type="string" value="Aerosol Index" />
           <attribute name="units" type="string" value="fraction" />
           <attribute name="_FillValue" type="float" value="NaN" />
           <attribute name="missing_value" type="float" value="NaN" />
       </variable>
   </netcdf>

Create Script AI_create.py

   from datafed import cf1
   
   def create():
       cf1.create_ncml22('AerosolIndex.nc', 'AerosolIndex.ncml', '64bitoffset')
   
   if __name__ == "__main__":
       create()