DQRID : D990611.1
Start DateStart TimeEnd DateEnd Time Data Quality Metric
SGP/AOS/C1 - Ozone Instrument Failure
DataStreams:sgpaosauxC1.a0, sgpaosC1.a0
A malfunction occurred with the AOS surface ozone instrument during the period 990507 1556 
GMT to 990514 1445 GMT.  The instrument reported an ozone concentration of 9.91e-01 ppm 
(991 ppb) continuously during this time.  Quality checking of the data the following week 
revealed that the problem began at about the time weekly maintenance check was made on 
Friday.  The problem continued until the next weekly maintenance check was done.  Site Ops 
was notified by the mentor of the problem on Friday, 5/14/99, and a technician was sent 
to inspect the system.  No switches on the instrument front panel were found in the wrong 
position (for example, if the instrument was inadvertantly left in a calibration mode).  
By the time the technician arrived at the trailer, the instrument appeared to be working 
correctly.  No explanation is given as to why these erroneous values were being 
generated by the ozone instrument, except that possibly it locked up with the throwing of the 
weekly preventative maintenance switch and this problem was not corrected until the same 
switch was thrown the following week.
Do not use ozone data.
  • O3_Press
  • O3_Samp
  • O3_Temp
  • O3_SetPt
  • O3_Mode
  • O3_Zro
  • O3_Spn
  • O3_Offset
  • O3_LinHeater
  • O3_Cont
  • O3_Span
  • O3_LinTemp
  • Ozone

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