Figure 1 illustrates a typical cosine response of a Yankee Environmental Systems UVB-1 Pyranometer used in the USDA UV-B monitoring program. The black continuous line of the plot represents an ideal cosine response. The colored line is the actual cosine response function of meter serial number 930203 which was determined on the date listed in the legend in the center of the plot.
It should be noted that the network does not apply cosine correction to its broadband measurements. Grainger et al. (1993) have noted that the R-B type meters are `nearly azimuthally independent' citing standard errors of relative cosine responses of less than 0.1% for zeniths < 65 degrees and less than 2.7% everywhere else.