SGP/SIRS/E20 - Downwelling Shortwave PSP Damaged by Lightning

The PSP was damaged by a lightning strike on 8/04/05 (22:10 GMT).  Data from other 
radiometers are good after this event.  

The PSP, NIP and shaded 8-48 were replaced 8/17/05 and the system returned to service at 
18:40 GMT.

Downwelling Shortwave (DS) data from the unshaded PSP during this period is reported as 
0.0 W/sq m.  The DS can be computed from available Direct Normal (NIP), Downwelling Diffuse 
(DD), and the computed Solar Zenith Angle (SZA) using the following equation:

    DS = NIP * Cos(SZA) + DD

Estimated uncertainties of the computed values are actually lower than those of the 
measured DS  (+/- 3% or 4% vs. +/- 5% to 10% respectively, depending on SZA).

Calculate DS as suggested.

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

• (Raw data stream - documentation not supported)

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