SGP/SIRS/E33 - Reprocessed: Partial shading

Shading of the NIP radiometer occurred after sunrise each day of the reported date period, 
for a few minutes between 1145 and 1215 UTC. Issue was present in the shortwave direct 
normal variable as well as the associated min, max, and std variables. The shading was 
caused by the presence of a narrow antenna that was later relocated. 

The data have been reprocessed to set specific affected periods to the missing_value 
(-9999).  Specific times affected were:
    20120509: 1200-1201
    20120510: 1201-1202
    20120513: 1206-1207
    20120514: 1207-1208

• 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)

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