The tar file in this directory, UWHIRS_cloud_products.tar.gz, contains monthly mean cloud product files created at the 
Cooperative Institute for Meteorological Satellite Studies (CIMSS), University of Wisconsin-Madison.  The products are
derived from HIRS and AVHRR radiance data and stored at 0.5-degree spatial resolution.  The files are netcdf4 format.
HIRS data from NOAA-6 through METOP-b are used to create cloud top pressure altitudes and cloud effective emissivities 
via the CO2-slicing algorithm.  Associated AVHRR GAC data are collocated within individual HIRS FOVs and used for
cloud vs. clear sky discrimination.  The cloud products extend from May 1980 to March 2016.

Description of data set can be found here:
https://doi.org/10.1175/JAMC-D-16-0129.1