TWP/SKYRAD/C2 - Short direct normal

The short_direct_normal (NIP) data are missing or incorrect due to instrument cable 
failure.  The cable was replaced.

The short_direct_normal can be calculated using the following relationship for shortwave 
radiometers:
global hemispheric = diffuse hemispheric + direct normal *cos (zenith angle)

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

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