DQRID : D940105.1
Start DateStart TimeEnd DateEnd Time Data Quality Metric
07/11/1993110012/01/19931830Suspect
more
Subject:
Incorrect readings for pressure sensor
DataStreams:sgp5ebbrE15.b1, sgp30ebbrE15.b1, sgp15ebbrE15.b1
Description:
ARM PROBLEM IDENTIFICATION FORM (PIF)

                            PIF No. P940105.1

Subject:  SGP/Ebbr - Incorrect readings for pressure sensor at E15

Submitted By:        David R. Cook
    Organization:    Argonne National Laboratory
    Date Submitted:  December 13, 1993

How may we contact you?
    e-mail:  cook@anler.er.anl.gov
    phone:   (708) 252-5840
    FAX:     (708) 252-9792

Submitter's Priority: 3
    [Critical-1   Very Important-2 Important-3 Inconvenient-4 Interesting-5]

Where was this Problem Identified:  DA
    [Site Data System-SDS      Experiment Center-EC]
    [Archive-A At              Field Instrument-FI ]
    [During Data Analyis-DA    Other- List Location]

Does this PIF result in a Software Change Request?  No
    Where:                     [ SDS,  EC, or  A ]

    Type:                      [Development-1 Problem-2  Enhancement-3]

    List Programs/Documents Affected:

    Configuration Identification:

Does problem impact data values or cause data loss?  Data values.
    which platform(s): EBBR, E15, Ringwood, OK

    Specify (or estimate) begin and end dates
          Begin Date   7/11/93
          End   Date  12/01/93   Time  1830 GMT

    Apparent cause of data loss, if known:

    SUGGESTED CAUSES:   Calibration Drift.
    [human error, component failure, temperature, lightning          ]
    [foreign matter, power loss, software failure,                   ]
    [communications failure, modification difficulites, specify other]


Problem Description/Change Description.

o For Instrument Problems ONLY,
        Identify MODE of Operation: Normal

o Give a brief explanation with details, attach examples and any supporting
  information.  This should include a description of analysis leading to
  identification of problem and, if known, recommended action.


Beginning July 11, 1993, the atmospheric pressure sensor at the E15
EBBR began indicating approximately 0.2 KPa lower than the colocated SMOS.
Between July 31 and August 22, 1993 the difference increased to between
0.25 and 0.30 KPa.  After August 22, the difference increased to 0.3 to
0.35 KPa and remained that way until December 1, 1993.  A comparison of the
EBBR pressure sensor with the portable standard on December 1, 1993
indicated that the EBBR sensor was 0.04 KPa higher than the standard; this
is excellent agreement considering that the uncertainty of the EBBR sensor
calibration is 0.15 KPa.  The consistent bias in EBBR pressure between July 11
and December 1 can be easily detected in comparisons with SMOS pressure data.
No EBBR data other than pressure was affected by the pressure problem;
calculations of specific heat at constant pressure (which includes the term
1/(p-vp)) times other terms (including p-.378*vp) result in no error to the
third decimal point at least in the resulting Bowen Ratio.  For example;
assume a common vapor pressure (vp) of 2.0 kPa, a common atmospheric pressure
of 97.0 kPa, and a corrupted atmospheric pressure of 96.65 kPa at the extreme.

       Uncorrupted                               Corrupted

(97.0-.378*2.0)/(97.0-2.0) = 1.0131   (96.65-.378*2.0)/(96.65-2.0) = 1.0131

   1.0131/1.0131 = 1.0000    There is no effect on the Bowen Ratio as a
                                       result of the corruption.

Therefore, no correction to the quantities calculated using pressure is
needed.
Suggestions: 
Measurements:sgp5ebbrE15.b1:
  • time_offset
  • temp_air_bottom
  • vapor_pressure_top
  • temp_air_top
  • rh_bottom_fraction
  • wspd_arith_mean
  • vapor_pressure_bottom
  • wdir_vec_std
  • rh_top_fraction
  • lon
  • temp_reference
  • temp_trh_bottom
  • temp_trh_top
  • home_signal
  • wspd_vec_mean
  • alt
  • wdir_vec_mean
  • net_radiation
  • lat
  • base_time
  • atmos_pressure
more
sgp15ebbrE15.b1:
  • lon
  • soil_heat_flow_2_mv
  • atmos_pressure_mv
  • rh_right_mv
  • soil_heat_flow_5_mv
  • soil_temp_5_rr
  • soil_moisture_1_r
  • soil_moisture_5_r
  • battery_voltage
  • temp_reference_rr
  • base_time
  • soil_heat_flow_3_mv
  • net_radiation_mv
  • soil_temp_3_rr
  • soil_moisture_4_r
  • temp_air_left
  • soil_temp_4_rr
  • rh_left_mv
  • wdir_vec_mean_mv
  • home_signal
  • soil_heat_flow_1_mv
  • lat
  • soil_temp_1_rr
  • temp_air_right
  • temp_trh_left_rr
  • soil_moisture_3_r
  • alt
  • soil_heat_flow_4_mv
  • soil_temp_2_rr
  • temp_trh_right_rr
  • wspd_arith_mean
  • soil_moisture_2_r
  • time_offset
more
sgp30ebbrE15.b1:
  • soil_moisture_1
  • soil_moisture_2
  • soil_moisture_3
  • temp_air_bottom
  • soil_moisture_4
  • soil_moisture_5
  • corr_soil_heat_flow_4
  • corr_soil_heat_flow_3
  • corr_soil_heat_flow_2
  • corr_soil_heat_flow_1
  • alt
  • corr_soil_heat_flow_5
  • surface_soil_heat_flux_avg
  • wdir_vec_mean
  • soil_heat_flow_4
  • soil_heat_flow_5
  • soil_heat_flow_2
  • soil_heat_flow_3
  • soil_heat_flow_1
  • base_time
  • soil_heat_capacity_5
  • soil_heat_capacity_4
  • temp_reference
  • home_signal_15
  • lat
  • time_offset
  • rh_bottom_fraction
  • wspd_arith_mean
  • soil_heat_capacity_3
  • soil_heat_capacity_2
  • soil_heat_capacity_1
  • bowen_ratio
  • lon
  • wdir_vec_std
  • latent_heat_flux
  • surface_soil_heat_flux_5
  • sensible_heat_flux
  • surface_soil_heat_flux_3
  • surface_soil_heat_flux_4
  • atmos_pressure
  • home_signal_30
  • temp_trh_top
  • vapor_pressure_top
  • surface_soil_heat_flux_1
  • surface_soil_heat_flux_2
  • net_radiation
  • energy_storage_change_1
  • soil_temp_4
  • vapor_pressure_bottom
  • energy_storage_change_3
  • soil_temp_3
  • energy_storage_change_2
  • energy_storage_change_5
  • soil_temp_2
  • energy_storage_change_4
  • soil_temp_1
  • soil_temp_5
  • temp_trh_bottom
  • rh_top_fraction
  • temp_air_top
  • wspd_vec_mean
more

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