Bad virtual temps for air virtual temp above 30 dec C

DQR No:                               Platform:

Subject: Bad Virtual temps for air virtual temperature above 30 deg C.

Date Submitted:23 Nov 1994
Submitted By: Richard L. Coulter      _x_  Instrument Mentor
                                      ___  EST Member
                                      _x_  Science Team Member
                                      ___  Other _____________________________

For questions or problems, please contact the ARM Experiment Center at
509-375-6898 or via email at dqr@arm.gov.

Platform/Measurement:50 and 915 RASS temperatures
        What level data: (raw,a0,a1,b1,c1 etc):a0,a1,a2

    What location was the data collected at: CF

    Period of time in question
        Begin Date   6/1 /94     Time     :      (GMT)
        End Date     9/1 /94     Time     :      (GMT)

 Data should be labeled:
 _x__  questionable                    ___  All data fields affected
 _x_  incorrect                         _x_  Only some data fields affected
 ___  wrong calibration
 ___  others

 Discussion of Problem:
When operating the RASS, a temperature range is selected for system operation.
When the real-time data are analysed by the system, spectra are collected and
acoustic frequencies used that fit that temperature range.  For summertime
operation, the selected temperature range was -11 to +30 C.  Maximum temperature
s
in the lower 500 m sometimes exceeded 30 deg. C.  When this happened, the report
ed
temperatures were usually near 30 - 31 deg rather than the correct (higher) valu
e.
One might have expected the system to report no good data through its internal
QC; however the digital FFT spreads energy from the central peak through
neighboring frequency bins; this leads to energy in the maximum FFT bin allowed
and results in erroneous temperatures.



Other observations/measurements impacted by this problem:



Suggested Corrections of the Problem: (e.g. change calibration factor and
recompute, flag data with this comment, etc.)
During summertime operation the maximum temperature should be 35 - 40 deg C.
In general, site operators and the instrument mentor need to be aware of the
range of temperatures to be expected and modify the system parameter files when
necessary.


Data Processing Notes                Date

• Development data stream - documentation not supported

• Development data stream - documentation not supported

• Development data stream - documentation not supported

• Development data stream - documentation not supported

• Development data stream - documentation not supported

• Development data stream - documentation not supported