SGP/SIRS/E9 - Possible instrument drift

Downwelling shortwave values were too low, dropping below -10 W/m^2 
                 at night and reading 30-50 W/m^2 lower than DS calculated from 
                 direct and diffuse measurements during the day. This problem became 
                 more noticeable beginning on 10/14, when nighttime values began to 
                 drop below -10 W/m^2 consistently. The problem was corrected with 
                 the annual instrument changout on 10/23/03.  

                   Although the downwelling shortwave instrument (DS) appears to be the 
                 problem a more likely scenario is that the cable connections became 

                 thermopile.  The instrument changeout possibly reseated and corrected 
                 any poor connections.

No corrections possible, use this data with discretion.

• Down-welling unshaded pyranometer voltage(down_short_hemisp)
• 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)

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

• (Raw data stream - documentation not supported)