PVC/QCRAD/M1 - PSP IR loss not corrected due to ventilation problems

During this period the ventilator fan for the PSP is not working as described in DQR 
D120913.1. This changes the relationship between the PIR and PSP (because the PIR ventilation 
is correct during this time), making the IR loss correction incorrect. Thus the PSP 
measured shortwave irradiance is more uncertain and should be used with caution. This is not 
generally a problem when using the recommended variable for downward shortwave irradiance, 
BESW, which is usually the sum of the measured direct and diffuse irradiances during 
this period.

Use caution with measurements from the PSP. This should not be a problem if following 

the recommended practice of using the best estimate shortwave (BESW) variable for 
downward shortwave irradiance during this time.

• down_short_hemisp