DQRID : D950921.3
Start DateStart TimeEnd DateEnd Time Data Quality Metric
07/20/1995170009/14/19951830Incorrect
more
Subject:
SGP/EBBR/E12 - AEM replacement
DataStreams:sgp5ebbrE12.b1, sgp30ebbrE12.b1
Description:
Please see DQR P950816.2, where this problem was first documented.

As noted in a previous DQR, the home signal values at E12, Pawhuska, OK
began decreasing in July.  At the beginning of the period listed, the home
30 value dropped below 15; this causes a data quality message to be output in
the site operations log as the stated acceptable range for home 30 is 15 to
34.999999.  No data is incorrect as a result of this condition.

The home 15 value dropped below 35 beginning July 21, 1995, sometime after
2000 GMT; this causes a data quality message to be output in the site
operations log as the stated acceptable range for home 15 is 35 to
70.  Data is incorrect as a result of this condition, that being 30 minute e,
h, and bowen.

The home values frequently dropped below their proper levels until 10 August,
1995, at some time after 1100 GMT, when the set screws in the AEM would no
longer hold and the aspirator units were stranded inbetween the home
positions.  Thereafter, the reported home signals were negative.  All 30
minute e, h, and bowen data are incorrect for this condition.

On August 16, 1995, at about 1600 GMT, site operators determined that they
could not repair the AEM on-site and they determined that the replacement AEM
that they took with them has an electronic short.  Therefore, the AEM was
left in manual mode (no exchange).  All 30 minute e, h, and bowen data are
incorrect until the end of the period listed above.

On 13 September 1995 site operations personnel replaced the AEM
(old S/N 92005, new S/N 94008).  The new AEM would not exchange when the
right sensor was in the home position: this was confirmed on 14 September
when site operations personnel again visited the site.  However, soon after
the site operations personnel left Pawhuska on 14 September (at 1810 GMT),
the AEM started to exchange properly (data correct for 1900 GMT and after).
The AEM continues to operate properly.
Suggestions: 
Measurements:sgp5ebbrE12.b1:
  • home_signal
more
sgp30ebbrE12.b1:
  • home_signal_15
  • sensible_heat_flux
  • latent_heat_flux
  • home_signal_30
  • bowen_ratio
more

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