SGP/RL/C1 - Malfunction in WFOV data acquisition

A malfunction in the data acquisition hardware resulted in corrupted data in the 
wide-field-of-view (WFOV) nitrogen, water vapor and elastic channels. The problem is so serious as 
to yield these signals useless during the period covered by this DQR.

Do not use any data products derived from the WFOV raw signals during the period covered 
by this DQR. This includes water vapor mixing ratio, aerosol scattering ratio, and aerosol 
extinction. 

The narrow-field-of-view (NFOV)channels are unaffected by this problem. So data products 
derived from only the NFOV channel should be okay. These include the 'high' channel 
signals from the merge VAP, depolarization and temperature.

• Raman backscatter, number of photons counted in the low nitrogen channel(nitrogen_counts_low)
• elastic_counts_low
• water_counts_low

SGP/RL/C1 - Frequent intermittent drop-outs in the WFOV photon counting signals

Beginning suddenly, near 1330 UTC on 31 May 2011, the liquid water and all three WFOV 
channels began showing intermittent and frequent “drop-outs” in the photon counting signals. 
These drop-outs were periods when the signal would momentarily fade and then come back. 

This problem, which was traced to a malfunction of the Licel data recorders, occurred at 
irregular intervals and with such frequency as to render the data from the affected 
channels useless. This problem persisted until repairs were made to the Licel transient 
recorders on 19 August 2011. 

Although only the WFOV channels (and liquid water channel) were affected, the aerosol and 
water vapor mixing ratio VAPs are computed by combining NFOV and WFOV channels. Thus, all 
of these higher level data products were adversely impacted by the drop-out problem.

The NFOV data in the sgprlC1.a0 and sgprlprofmerge1turnC1.c0 datastreams were unaffected 
by the "drop-out" problem. These signals could be used to compute aerosol optical 
properties and water vapor mixing ratio.

• water_analog_low
• Raman backscatter, number of photons counted in the low nitrogen channel(nitrogen_counts_low)
• nitrogen_analog_low
• elastic_counts_low
• liquid_counts_high
• water_counts_low
• elastic_analog_low
• liquid_analog_high