Cloud Amount Statistics (CMATRIX) from the NIMBUS-7 Temperature Humidity Infrared Radiometer (THIR)

The CMATRIX cloud data contain daytime and nighttime cloud amounts in percent cloud cover, cloud amount in low, middle, and high altitude categories, cirrus and deep convective cloud amount, and radiances of cloud and clear scenes. Both daily and monthly means are included. The CMATRIX data, available on the 500 km x 500 km Earth Radiation Budget (ERB) target area grid, also includes the variances of cloud amounts and radiance. This data set was derived from the Nimbus-7 Temperature Humidity Infrared Radiometer (THIR) data, the Nimbus-7 Total Ozone Mapping Spectrometer (TOMS) inferred reflectivity, surface temperature, climatological temperature lapse rate, and snow/ice data from U. S. Air Force nephanalysis. The weekly tapes, NCLE, were used to generate CMATRIX tape. There is one CMATRIX tape per Nimbus-7 data year (November - October) and each data file contains one month worth of data. Other independent data sets from the Nimbus-7 ERB and SMMR may be of interest as well as the ISCCP cloud data.