SGP/SIRS/E7 - NIP failure

The short_direct_normal data were reported as -9999 during this time period. The start of 
the bad data from the NIP instrument on 05/12 coincides with a SMOS report of 2 inches of 
rain.  

NIP data are not recoverable. Users can calculate short_direct normal component using 
component sum method as follows (for each minute of available data):

short_direct_normal = (down_short_hemisp - down_short_diffuse_hemisp)/cos(zenith angle)

• Instantaneous direct normal shortwave irradiance, pyrheliometer thermopile
  voltage(inst_direct_normal)

• Shortwave direct normal irradiance, pyrheliometer(short_direct_normal)
• Shortwave direct normal irradiance, pyrheliometer, minima(short_direct_normal_min)
• Shortwave Direct Normal Irradiance, Pyrgeometer, Standard Deviation(short_direct_normal_std)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)