Start Date | Start Time | End Date | End Time | Data Quality Metric |
---|---|---|---|---|
07/11/1993 | 1100 | 12/01/1993 | 1830 | Suspect |
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: more
sgp15ebbrE15.b1: more sgp30ebbrE15.b1: more |