| DQR ID | Subject | Affected Data Streams | Data Quality Metric |
|---|---|---|---|
| D941021.2 | SGP/EBBR/E20 - Aspirator Fan Stoppage | sgp30ebbrE20.b1 | Incorrect |
| D940105.8 | SGP/EBBR/E20 - Reprocess: Questionable data in soil heat fluxes at E20 | sgp30ebbrE20.b1 | Incorrect |
| D941021.9 | SGP/EBBR/E20 - Net Radiometer Hemisphere Changes | sgp30ebbrE20.b1 | Suspect |
| D940329.2 | SGP/EBBR/E20 - Pressure Sensor Malfunction | sgp5ebbrE20.b1 | Incorrect |
| D020628.18 | SGP/EBBR/E20 - T/RH Check | sgp5ebbrE20.b1 | Incorrect |
| D941021.7 | SGP/EBBR/E20 - Net Radiometer Hemisphere Changes | sgp30ebbrE20.b1 | Incorrect |
| D941021.1 | SGP/EBBR/E20 - Soil Moisture Probe Failure | sgp30ebbrE20.b1 | Incorrect |
| D940616.4 | SGP/EBBR/E20 - Soil Moisture Probe | sgp30ebbrE20.b1 | Incorrect |
| D940921.1 | SGP/EBBR/E20 - Fan Stopped, T and RH Biases | sgp5ebbrE20.b1 | Incorrect |
| D021113.4 | SGP/EBBR - Incorrect Units for Soil Heat Capacity (cs1, cs2, cs3, cs4, cs5) in 30EBBR Header | sgp30ebbrE13.b1 | Note |
| D940105.2 | SGP/EBBR/E20 - Blown fuse in AEM at E20 | sgp30ebbrE20.b1 | Incorrect |
| Start Date | Start Time | End Date | End Time | Data Quality Metric |
|---|---|---|---|---|
| 1994-09-29 | 15:30:00 | 1994-09-29 | 17:30:00 | Incorrect |
| Subject: | SGP/EBBR/E20 - Aspirator Fan Stoppage |
|---|---|
| Affected Datastreams: | sgp30ebbrE20.b1 |
| Description | During Site Operations Preventative Maintenance activities the left AEM fan stopped operating. This affected some of the data being collected. The times of incorrect values are listed below. 15 minute: 1530-1715 GMT; tair_l, mv_hum_l, rr_thum_l 30 minute: 1530-1730 GMT; thum_top, thum_bot, tair_top, tair_bot, hum_top, hum_bot, e, h, bowen |
| Measurements |
|
| Start Date | Start Time | End Date | End Time | Data Quality Metric |
|---|---|---|---|---|
| 1993-11-24 | 12:15:00 | 1993-11-24 | 15:15:00 | Incorrect |
| Subject: | SGP/EBBR/E20 - Reprocess: Questionable data in soil heat fluxes at E20 |
|---|---|
| Affected Datastreams: | sgp30ebbrE20.b1 |
| Description | Soil heat flux probes #4 had been indicating soil heat fluxes that were higher than the other four probes. It was decided to replace it. On November 24, 1993 Soil Heat Flux probe #4 was replaced, resulting in outputs more similar to the other four probes. This PIF does not invalidate previous measurements by the old probe #4, but only indicates data that is bad as a result of the replacement procedure. This procedure resulted in some bad data for the adjoining soil heat flux probes #3 and #5 also. Bad data for #3 includes the 1600 GMT half hour, and 5 and 15 minute periods between 1530 and 1600 GMT. Bad data for #4 includes half hour times of 1600 through 1900 GMT, with 5 and 15 minute data inbetween those times being invalid as well. Bad data for #5 includes half hour times of 1630 and 1700 GMT, with 5 and 15 minute periods inbetween those times being invalid as well. Corrupted 30 minute values of shf4, c_shf4, g4, ave_shf, h, and e, and corrupted 15 minute values of mv_hft4 resulted. The quantities shf4, c_shf4, g4, and mv_hft4 are bad data values and are not recoverable. The other quantities can be recalculated using the remaining functioning set(s) of soil sensors. Use the following equations: ave_shf = (gs summed)/n, where n is the number of probes functioning e = -(q + ave_shf)/(1 + bowen) where q is net radiation, and bowen is Bowen Ratio h = e * bowen |
| Measurements |
|
| Start Date | Start Time | End Date | End Time | Data Quality Metric |
|---|---|---|---|---|
| 1994-09-14 | 16:00:00 | 1994-09-29 | 17:35:00 | Suspect |
| Subject: | SGP/EBBR/E20 - Net Radiometer Hemisphere Changes |
|---|---|
| Affected Datastreams: | sgp30ebbrE20.b1 |
| Description | The upper hemisphere of the net radiometer at the site was punctured allowing water to collect in the lower (and sometimes upper) section of the sensor. The punctures are most likely the result of migratory birds (a problem that we have experienced almost every year here at ANL also). The punctures (and water in some net radiometers) did not result in obvious invalidation of the data. Whether there is water in the lower hemisphere or not, a small puncture of the upper hemisphere would not have a major effect on the net radiation measurement. Significant amounts of water in the lower hemisphere should have a major effect on nighttime measurements particularly, although that effect is hard to detect in the data. The date when the puncture occurred is approximate - but is certainly no more than two weeks before the hemisphere was replaced. |
| Measurements |
|
| Start Date | Start Time | End Date | End Time | Data Quality Metric |
|---|---|---|---|---|
| 1994-03-17 | 16:00:00 | 1994-03-17 | 16:30:00 | Incorrect |
| Subject: | SGP/EBBR/E20 - Pressure Sensor Malfunction |
|---|---|
| Affected Datastreams: | sgp5ebbrE20.b1 |
| Description | Pressure sensor malfunction during attempt to monitor it during Preventative Maintenance visit. 30 minute values of pressure for 1600 GMT and 1630 GMT, 15 minute values for 1600, 1615, and 1630, and 5 minute values for 1600, 1605, 1610, 1615, 1620, 1625, and 1630 GMT are incorrect. However, the range of the incorrect values was such as to not adversely affect flux measurements. Some noise was apparently induced in the pressure output voltage as a result of the monitoring, although it is not known how. |
| Measurements |
|
| Start Date | Start Time | End Date | End Time | Data Quality Metric |
|---|---|---|---|---|
| 1994-11-10 | 15:20:00 | 1994-11-10 | 16:30:00 | Incorrect |
| Subject: | SGP/EBBR/E20 - T/RH Check |
|---|---|
| Affected Datastreams: | sgp5ebbrE20.b1 |
| Description | During the month of November 1994, site operations personnel conducted field comparisons of the temperature and relative humidity sensors in the EBBRs and the HMI31 portable T/RH meter (with the removable probe). As is reflected in the home signal output, the automatic exchange mechanism was disabled in order to conduct the checks. Measurements were taken every 5 minutes, for a half hour each in the aspirated radiation shields (the HMI31 was inserted into the EBBR aspirated radiation shield to provide the same aspiration as the EBBR sensors received). Measurements of aspirator flow were also recorded. This information was provided to the mentor. The mentor then compared the field checks with the data recorded by the EBBRs. The periods of data and data fields that are incorrect because of the checks are listed below. Times are those at which the data are reported. Data Fields 5 minute: tair_top, tair_bot, thum_top, thum_bot, hum_top, hum_bot, vp_top, vp_bot 15 minute: rr_thum_r, rr_thum_l, mv_hum_r, mv_hum_l, tair_r, tair_l 30 minute: tair_top, tair_bot, thum_top, thum_bot, hum_top, hum_bot, vp_top, vp_bot, bowen, e, h 5 minute: 1520, 1525, 1530, 1535, 1540, 1545, 1550, 1555, 1600, 1605 15 minute: 1530, 1545, 1600, 1615 30 minute: 1530, 1600, 1630 (EDITOR'S NOTE: The following analysis refers to all EBBRs installed in Nov 1994) Results of the T/RH comparisons: The combined accuracy of the HMI31 and EBBR temperature sensors (thermocouples or PRTDs) is +/- 0.4 degrees C. The combined accuracy of the HMI31 and EBBR RH sensors is +/- 4% for RH less than 80%, and +/- 6% for RH greater than 80%. The combined accuracy for each pair of EBBR sensors of the same type is essentially the same as the quantities stated above. All of the pairs of EBBR sensors show differences that fall within the stated combined accuracies. Although this sounds wonderful, a few of the differences are close to the combined accuracy, which, because of the small differences in temperature being measured (normally smaller than the magnitude of the combined accuracy) could lead to some incorrect estimation of sensible and latent heat flux. However, unless there would be substantial differences of calibration slope of two sensors in a pair, the switching of height of the sensors every 15 minutes by the automatic exchange mechanism will remove the offset between the sensors. The comparisons between the EBBR sensors and the HMI31 T/RH meter showed much larger differences. The range of differences were: -2.4 to 0.0 degrees for the thermocouples, -2.1 to 0.1 degrees for the RH probe PRTDs, and -6.6 to 6.7 percent for the RH sensors. Six Thermocouples indicated differences from the HMI31 greater than the combined accuracy. Seven PRTDs indicated differences from the HMI31 greater than the combined accuracy. Four RH sensors indicated differences from the HMI31 greater than the combined accuracy. The temperature differences (for both thermocouples and PRTDs) were nearly all of one sign; the HMI31 indicated the greater temperature, which may suggest a bias in the HMI31 temperature measurement, even though a dozen differences of +/- 0.2 degrees were measured. Four differences of zero and only one positive difference (out of 40) were measured. Thirteen of the 20 RH differences were positive (HMI31 indicating the lower RH), with the differences near the level of the combined accuracies being approximately 50% positive and 50% negative. It does not appear that the HMI31 has a RH bias. Plots of EBBR sensor/HMI31 differences as a function of time from the installation of the individual sensors (a range of 10 to 30 months in the field) shows no obvious pattern of sensor drift with time. This is encouraging. |
| Measurements |
|
| Start Date | Start Time | End Date | End Time | Data Quality Metric |
|---|---|---|---|---|
| 1994-09-29 | 17:15:00 | 1994-09-29 | 18:00:00 | Incorrect |
| Subject: | SGP/EBBR/E20 - Net Radiometer Hemisphere Changes |
|---|---|
| Affected Datastreams: | sgp30ebbrE20.b1 |
| Description | Incorrect data during hemisphere change. |
| Measurements |
|
| Start Date | Start Time | End Date | End Time | Data Quality Metric |
|---|---|---|---|---|
| 1994-09-29 | 15:30:00 | 1994-09-29 | 16:00:00 | Incorrect |
| Subject: | SGP/EBBR/E20 - Soil Moisture Probe Failure |
|---|---|
| Affected Datastreams: | sgp30ebbrE20.b1 |
| Description | Soil moisture probe #4 went offscale for a short period, for unknown reasons. However, it may have resulted from Site Operations Preventative Maintenance activities that were taking place at the time. The times of incorrect values are listed below. 30 minute: 1600 GMT; sm4, c_shf4, cs4, ces4, g4, ave_shf, e, h 15 minute: 1600 GMT; r_sm4 |
| Measurements |
|
| Start Date | Start Time | End Date | End Time | Data Quality Metric |
|---|---|---|---|---|
| 1994-05-06 | 16:00:00 | 1994-06-09 | 15:45:00 | Incorrect |
| Subject: | SGP/EBBR/E20 - Soil Moisture Probe |
|---|---|
| Affected Datastreams: | sgp30ebbrE20.b1 |
| Description | Beginning on May 6, 1994, soil moisture probe #3 began a long decline in output and sensitivity until it stabilized at a low value of around 7, with virtually no sensitivity at midday (GMT) on May 22, 1994. The output remained around this low value until the probe was replaced on June 9, 1994 at 1545 GMT. Old Probe S/N 92038, New Probe S/N 93003. |
| Measurements |
|
| Start Date | Start Time | End Date | End Time | Data Quality Metric |
|---|---|---|---|---|
| 1994-09-12 | 13:00:00 | 1994-09-14 | 18:47:00 | Incorrect |
| Subject: | SGP/EBBR/E20 - Fan Stopped, T and RH Biases |
|---|---|
| Affected Datastreams: | sgp5ebbrE20.b1 |
| Description | Another fan stoppage situation occurred. This is the fourth one in the last few months and may indicate a weakening of the fans that aspirate the temperature, relative humidity housings. The 15 minute data reveals that the stoppage occurred at approximately 1300 GMT on September 12. The left fan was cleaned out by site operations personnel and began running again at 1847 GMT on September 14. The 15 minute data during this period shows that during daytime, the left temperature was greater than the right temperature and that the left relative humidity was lower than the right relative humidity (a consequence of greater temperature), irregardless of the positions of the housings. The bowen ratio, sensible heat flux and latent heat flux for this period, as well as all left housing temperatures and relative humidities are incorrect. The data values that are incorrect are: 5 minute: tair_top, tair_bot, thum_top, thum_bot, hum_top, hum_bot, vp_top, vp_bot 15 minute: rr_thum_l, mv_hum_l, tair_l, 30 minute: tair_top, tair_bot, thum_top, thum_bot, hum_top, thum_bot, vp_top, vp_bot, bowen, e, h Because of the increased frequency of fan stoppage occurrences, I have submitted a work request to site operations to use the portable vane anemometer to check the flow of the housing fans on each EBBR and visually check (and clean if needed) the fans for debris that would restrict the flow. Included in this work request are instructions for checking the performance of the temperature and relative humidity sensors by manually putting the aspirator housings at the same height for a half hour period (so that two 15 minute and one half hour comparison result). The latter part of the work request is prompted by my close inspection of the Meeker data for the last few weeks. It is clear that significant biases have developed in the pairs of temperature and relative humidity sensors; left thermocouple ~0.5 deg. C greater than right thermocouple, left relative humidity ~5% lower than right relative humidity. Biases were expected in operating the systems over long time periods, and these appear to be the result of simple offsets, not changes in calibrations. At this point, I just want to determine how large the offsets are. Comparison of these offsets between EBBR units, in light of the different lengths of time that EBBR units and individual sensors have been deployed, may provide some interesting information on likely offset changes with time. |
| Measurements |
|
| Start Date | Start Time | End Date | End Time | Data Quality Metric |
|---|---|---|---|---|
| 1993-12-01 | 12:00:00 | 2003-06-18 | 11:59:00 | Note |
| Subject: | SGP/EBBR - Incorrect Units for Soil Heat Capacity (cs1, cs2, cs3, cs4, cs5) in 30EBBR Header |
|---|---|
| Affected Datastreams: | sgp30ebbrE13.b1 |
| Description | The units for Soil Heat Capacity (cs1, cs2, cs3, cs4, cs5) in the EBBR 30 minute netcdf header have been incorrect from the beginning of processing the data into netcdf files. The correct units are MJ/m^3/C. This does not affect the data quality. (NOTE: The actual begin date of some of these data streams is as early as 7/4/93. This DQR applies to all 30m EBBR data.) |
| Measurements |
|
| Start Date | Start Time | End Date | End Time | Data Quality Metric |
|---|---|---|---|---|
| 1993-10-30 | 13:00:00 | 1993-11-12 | 16:00:00 | Incorrect |
| Subject: | SGP/EBBR/E20 - Blown fuse in AEM at E20 |
|---|---|
| Affected Datastreams: | sgp30ebbrE20.b1 |
| Description | On October 30, 1993, before 1300 GMT, the fuse in the AEM (Automatic Exchange Mechanism) of Meeker, Ok (E20) EBBR blew out. The AEM remained nonfunctional until the fuse was replaced just before 1600 GMT on November 12, 1993. This situation resulted in the following invalid data: 5 minute: tair_top, tair_bot, thum_top, thum_bot, hum_top, hum_bot, vp_top, vp_bot, home 15 minute: rr_thum_r, rr_thum_l, mv_hum_r, mv_hum_l, mv_home, tair_r, tair_l 30 minute: tair_top, tair_bot, thum_top, thum_bot, hum_top, hum_bot, vp_top, vp_bot, bowen, e, h, home_15, home_30 If the biases of the sensors were know, bowen, h, and e could be recalculated from the 15 minute and/or 5 minute data. Since we will not have any idea of what those biases are until an annual calibration of the sensors can take place (which may be months away), the recalculations cannot be performed at this time. Furthermore, it may be invalid to use sensor biases, if determined too far removed in time, due to the gradual calibration drift of some of the sensors. |
| Measurements |
|