SGP/SIRS/C1 - Monthly Summary

dominant problem here is the daytime 3 component problem. Direct and Diffuse are
always too high and Global is too low. The problem occurs around the time that the
testing regime switches from twilight to daytime testing regimes or from daytime to
twilight. The flags occur in significant numbers on the 1st - 5th, 8th - 20th, 24th - 
28th,
30th, and 31st. The failures vary in magnitude and duration. The worst flags for a 
particular
day is typically high level yellow, with respect to this problem. Global goes below
daytime empirical limits on both the 5th and 6th for substantial periods of time. Diffuse
also goes below daytime empirical limits on the 6th in the evening. Upwelling Longwave is
below empirical limits on the 24th. This may not be a problem, as many sites exhibited
the same problem on the same night. Exceptionally cold temperatures may be the cause.
Direct also exceeds its daytime empirical limit on the 1st, 4th, 10th, 13th, 14th, and 
20th. This occurs
at the changeover from medium to high air mass and does not last for longer than 30 
minutes.

Applying the responsivity as a function of the zenith angle,
rather than the constant zenith angle will help with the 3 component failures.
The Longwave data on the 24th is probably OK, too.

• Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer(down_short_diffuse_hemisp)
• Down-welling unshaded pyranometer voltage(down_short_hemisp)
• Downwelling longwave hemispheric irradiance, shaded pyrgeometer(down_long_hemisp_shaded)
• 25 meter Upwelling Shortwave Hemispheric Irradiance, Pyranometer(up_short_hemisp)
• 10 meter Upwelling Longwave Hemispheric Irradiance, Pyrgeometer(up_long_hemisp)
• Shortwave direct normal irradiance, pyrheliometer(short_direct_normal)