Diference between upward and downward IR vs Cloud cover

Using the same data source as below.
Here is the effect on downward/upward radiation of various cloud cover percentages (both total and opaque cloud)

Location of measurements

NREL Solar Radiation Research Laboratory

Baseline Measurement System BMS

Latitude: 39.742^o North
Longitude: 105.18^o West
Elevation: 1828.8 meters AMSL