SGP/SIRS/E2 - Ventilator Fan Failure

Measured downwelling shortwave data was very questionable, reporting 
nighttime values as low as -50 W/m^2, while differing from calculated 
downwelling shortwave by as much as 50 W/m^2 lower during the day. The 
first indication of a problem was around 10 UTC, 9/14, when measured 
DS values suddenly dropped below 10 W/m^2 for about a 2 hour period 
before sunrise, then were consistently lower than calculated DS by as 
much as 40 W/m^2 during the day.

The problem got progressively worse with time until the ventilator fan was
replace on 9/25.  Ventilator fan failure changed the fundamental
operating characteristics of this PSP and resulted in unpredictable biased
measurements which cannot be corrected without additional empirical
characterization of the radiometer in question.

Disregard this data.

• Instantaneous Downwelling Hemispheric Shortwave, Pyranometer Thermopile Voltage(inst_global)

• (Raw data stream - documentation not supported)

• Downwelling shortwave hemispheric irradiance, pyranometer, maxima(down_short_hemisp_max)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyrgeometer, Standard
  Deviation(down_short_hemisp_std)
• Downwelling Shortwave Hemispheric Irradiance, Pyranometer, Minima(down_short_hemisp_min)
• Down-welling unshaded pyranometer voltage(down_short_hemisp)