SGP/AOS/C1 - Data processing problem

The AOS data was reprocessed for the AMF, SGP and NSA sites. There was an error in the 
processing of the corrections for the PSAP absorption signal such that a low pass filter was 
implemented for the scattering data used in these corrections.The difference between the 
corrected and previous data is < 0.05 Mm-1 (below the instrument detection limit) and 
should not have a significant effect on the previous data. Data will be reprocessed at a 
later time when more significant changes to the data processing are implemented.

• Aerosol light absorption coefficient, green channel, 10 um particle diameter(Ba_G_Dry_10um_PSAP1W_1)
• Absorption coefficient, green wavelength, low RH, 1 um size cut(Ba_G_Dry_1um_PSAP1W_1)

SGP/AOS/C1 - CPC leak

There was a slow internal leak in the CPC instrument and the data slowly decreased over 
time. The CN concentration is a lower limit and is likely 5 to 20% lower than the actual 
value with higher errors toward the end of the DQR period. The problem was fixed by 
replacing the CPC saturator block.

• N_CPC_1_std
• N_CPC_1_N
• N_OPC_1_N