The table below contains the quality flag associated with dissolved oxygen calbration evaluations and the associated comments, beginning with the most recent. Refer to the QA/QC general information page for information on the different quality levels.
SATURN-03
| Quality Flag | start time | end time | comment |
|---|---|---|---|
| QL2 | 6/5/20 | 12/1/20 | CODEPLOYED SENSOR: 6/5/20- 12/1/20: An optical dissolved oxygen sensor was deployed at SATURN-03 on 6/5/20: Both the previous sensor check prior to deployment as well as the in-situ DI readings suggest that this sensor had an offset of approximately 3.6% upon deployment. Regular DI readings were used to evaluate and quantify linear sensor drift to a calibration offset of approximately -7% (in 100% aerated DI water) at the end of Nov. 2020. A correction for this drift has been applied to the data. |
| QL2 | 7/27/20 | 12/1/20 | CODEPLOYED SENSOR: 7/27/20 – 12/1/20: The dissolved oxygen sensor deployed at SATURN-03 was one of two DO sensors deployed during this time period. This sensor was an SBE43 electrochemical type sensor while the other was an SBE63 optical type sensor. There were regular/weekly in-situ aerated DI readings during this period allowing for a clear quantification of sensor drift during this period from an approximate -2.7% offset in 100% aerated DI upon deployment to an approximate -10.0% offset in 100% aerated DI at the end of November. DI readings showed that drift was linear during this time period. A correction for this calibration drift has been applied to the data. Because of the available data to inform the correction, these data have been flagged as QL2. |
| QL1 | 6/5/20 | 7/15/20 | PRELIMINARY: 6/5/20- 7/1/20: An optical dissolved oxygen sensor was deployed at SATURN-03 on 6/5/20: Both the previous sensor check prior to deployment as well as the initial in-situ DI readings suggest that this sensor has a stable offset of approximately 3.8% A preliminary correction for this offset has been applied to the data. A final evaluation and corrections for calibration drift will be conducted once additional data have been collected. |
| QL4 | 3/23/20 | 7/13/20 | 10/23/19 – 7/13/20: The dissolved oxygen sensor at SATURN-03 was replaced on 10/23/19: The previous sensor check showed the sensor to be reading 100% (in 100% aerated DI water). This sensor began drifting following deployment and corrections for this drift have been made based on in-situ DI readings. The drift reached approximately 4% on 2/10/20 and then 7% on March 23, 2020, after which drift greatly accelerated. Based on the extent and speed of drift, the drift-corrected data prior to 2/10/20 have been flagged as QL2; the data between 2/10/20 and 3/23/20 have been flagged as QL3. While the data between 3/23/20 and 5/15/20 have been corrected, these data should be used with caution and have been flagged as poor (QL4). See supporting document: /s3-do09.pdf |
| QL3 | 2/10/20 | 3/23/20 | 10/23/19 – 7/13/20: The dissolved oxygen sensor at SATURN-03 was replaced on 10/23/19: The previous sensor check showed the sensor to be reading 100% (in 100% aerated DI water). This sensor began drifting following deployment and corrections for this drift have been made based on in-situ DI readings. The drift reached approximately 4% on 2/10/20 and then 7% on March 23, 2020, after which drift greatly accelerated. Based on the extent and speed of drift, the drift-corrected data prior to 2/10/20 have been flagged as QL2; the data between 2/10/20 and 3/23/20 have been flagged as QL3. While the data between 3/23/20 and 5/15/20 have been corrected, these data should be used with caution and have been flagged as poor (QL4). See supporting document: /s3-do09.pdf |
| QL2 | 11/4/19 | 2/10/20 | 10/23/19 – 7/13/20: The dissolved oxygen sensor at SATURN-03 was replaced on 10/23/19: The previous sensor check showed the sensor to be reading 100% (in 100% aerated DI water). This sensor began drifting following deployment and corrections for this drift have been made based on in-situ DI readings. The drift reached approximately 4% on 2/10/20 and then 7% on March 23, 2020, after which drift greatly accelerated. Based on the extent and speed of drift, the drift-corrected data prior to 2/10/20 have been flagged as QL2; the data between 2/10/20 and 3/23/20 have been flagged as QL3. While the data between 3/23/20 and 5/15/20 have been corrected, these data should be used with caution and have been flagged as poor (QL4). See supporting document: /s3-do09.pdf |
| QL1 | 10/23/19 13:15 | 11/4/19 | 10/23/19 – 7/13/20: The dissolved oxygen sensor at SATURN-03 was replaced on 10/23/19: The previous sensor check showed the sensor to be reading 100% (in 100% aerated DI water). This sensor began drifting following deployment and corrections for this drift have been made based on in-situ DI readings. The drift reached approximately 4% on 2/10/20 and then 7% on March 23, 2020, after which drift greatly accelerated. Based on the extent and speed of drift, the drift-corrected data prior to 2/10/20 have been flagged as QL2; the data between 2/10/20 and 3/23/20 have been flagged as QL3. While the data between 3/23/20 and 5/15/20 have been corrected, these data should be used with caution and have been flagged as poor (QL4). See supporting document: /s3-do09.pdf |
| QL4 | 9/3/19 | 10/23/19 13:15 | 9/3/19 – 10/23/19: The dissolved oxygen sensor at SATURN-03 began drifting significantly after 9/3/19 from reading approximately 10% low to reading 35% low on 10/23/19 (based on in situ aerated DI readings). While a correction for this drift has been applied to the data, these data have been labelled poor (QL4) and should be used with caution. See supporting document: /s3-do09.pdf |
| QL3 | 4/19/19 | 9/3/19 10:00 | 4/19/19 – 9/3/19: The dissolved oxygen sensor at SATURN-03 was replaced on 4/19/19. DI readings show that the new sensor calibration was reading approximately 4.6% low upon deployment and drifted to an approximate -8% calibration drift on 8/19/19 and then to a -10.6% drift on 9/3/19. Data have been corrected for this drift (assuming linear drift) and the data have been flagged as QL3. Corrections should be considered approximate. See supporting document: /s3-do09.pdf |
| QL5 | 3/25/19 | 4/19/19 | 2/21/19 – 4/19/19: The dissolved oxygen sensor was replaced at SATURN-03 at the end of February 2019 and was deployed through mid-April. This sensor was checked and reporting within manufacturer specifications prior to deployment. DI readings, and comparison with data from other stations suggest that the sensor only drifted slightly through mid-March (reading an offset of approximately 4% on 3/13/19). Drift accelerated after this point, reaching ~ 12% on 3/25/19 and drifting excessively beyond this point. Approximate corrections have been applied to the data through 3/25/19. Data between 3/25/19 & the sensor recovery on 4/19/19 have been flagged as bad. Corrections should be considered approximate and the data used with caution. |
| QL3 | 3/13/19 | 3/25/19 | 2/21/19 – 4/19/19: The dissolved oxygen sensor was replaced at SATURN-03 at the end of February 2019 and was deployed through mid-April. This sensor was checked and reporting within manufacturer specifications prior to deployment. DI readings, and comparison with data from other stations suggest that the sensor only drifted slightly through mid-March (reading an offset of approximately 4% on 3/13/19). Drift accelerated after this point, reaching ~ 12% on 3/25/19 and drifting excessively beyond this point. Approximate corrections have been applied to the data through 3/25/19. Data between 3/25/19 & the sensor recovery on 4/19/19 have been flagged as bad. Corrections should be considered approximate and the data used with caution. |
| QL2 | 2/21/19 | 3/13/19 | 2/21/19 – 4/19/19: The dissolved oxygen sensor was replaced at SATURN-03 at the end of February 2019 and was deployed through mid-April. This sensor was checked and reporting within manufacturer specifications prior to deployment. DI readings, and comparison with data from other stations suggest that the sensor only drifted slightly through mid-March (reading an offset of approximately 4% on 3/13/19). Drift accelerated after this point, reaching ~ 12% on 3/25/19 and drifting excessively beyond this point. Approximate corrections have been applied to the data through 3/25/19. Data between 3/25/19 & the sensor recovery on 4/19/19 have been flagged as bad. Corrections should be considered approximate and the data used with caution. |
| QL4 | 1/12/19 | 2/21/19 | 8/21/18 – 2/21/19: The dissolved oxygen sensor was replaced at SATURN-03 at the end of August 2018 and was deployed through the end of February 2019. DI readings show that the new sensor calibration was reading within +/-2% upon deployment (~-1.6%) but drifted to an approximate -7.5% offset in mid-December after which the rate of drift increased with calibration drift reaching -18% when it was recovered & replaced on 2/22/19. Corrections for drift have been applied to the data and data between 1/12/19 & 2/22/19 have been flagged as QL4 due to the excessive drift during this time. Corrections should be considered approximate and the data used with caution. |
| QL3 | 12/12/18 | 1/12/19 | 8/21/18 – 2/21/19: The dissolved oxygen sensor was replaced at SATURN-03 at the end of August 2018 and was deployed through the end of February 2019. DI readings show that the new sensor calibration was reading within +/-2% upon deployment (~-1.6%) but drifted to an approximate -7.5% offset in mid-December after which the rate of drift increased with calibration drift reaching -18% when it was recovered & replaced on 2/22/19. Corrections for drift have been applied to the data and data between 1/12/19 & 2/22/19 have been flagged as QL4 due to the excessive drift during this time. Corrections should be considered approximate and the data used with caution. |
| QL2 | 8/21/18 | 12/12/18 | 8/21/18 – 2/21/19: The dissolved oxygen sensor was replaced at SATURN-03 at the end of August 2018 and was deployed through the end of February 2019. DI readings show that the new sensor calibration was reading within +/-2% upon deployment (~-1.6%) but drifted to an approximate -7.5% offset in mid-December after which the rate of drift increased with calibration drift reaching -18% when it was recovered & replaced on 2/22/19. Corrections for drift have been applied to the data and data between 1/12/19 & 2/22/19 have been flagged as QL4 due to the excessive drift during this time. Corrections should be considered approximate and the data used with caution. |
| QL3 | 5/1/18 | 8/21/18 | 5/1/18 – 8/21/18: The sensor continued to drift throughout the remainder of its deployment in May through August 2018. During May through mid-July the sensor drifted slightly more from an approximate ~9.8% offset to an ~11% offset, as indicated by on-station aerated DI water readings. After 7/16/18 through the end of the deployment on 8/21/18, the DI readings indicate additional drift to an approximate ~14% offset. The data have been corrected based on these measurements of drift. Corrections should be considered approximate. |
| QL3 | 1/22/18 | 5/1/18 | 1/8/18 – 5/1/18: The sensor was replaced on 1/8/18. The new sensor was checked prior to deployment and was found to be reading within manufacturer specifications (reading 98.2% in 100% aerated DI). On-station aerated DI readings indicate that on 1/22/18 the sensor was reading with an approximate offset of -6% after which the DI readings show a continued linear drift until 4/9/18 after which the data stabilized at an approximate -9.8% offset through the end of April. The data have been corrected based on these measurements of drift. Corrections should be considered approximate. |
| QL2 | 1/8/18 | 1/22/18 | 1/8/18 – 5/1/18: The sensor was replaced on 1/8/18. The new sensor was checked prior to deployment and was found to be reading within manufacturer specifications (reading 98.2% in 100% aerated DI). On-station aerated DI readings indicate that on 1/22/18 the sensor was reading with an approximate offset of -6% after which the DI readings show a continued linear drift until 4/9/18 after which the data stabilized at an approximate -9.8% offset through the end of April. The data have been corrected based on these measurements of drift. Corrections should be considered approximate. |
| QL4 | 12/18/17 | 1/8/18 | 12/18/17 – 1/8/18: On-station aerated DI readings indicate that the DO sensor had a significant offset of approximately 12.14% on 12/18/17 and then continued to drift to an offset of approximately 14% on 1/8/18 when it was recovered from the station. The data have been corrected for this drift. Corrections should be considered approximate. Due to the degree of offset and continued drift of the sensor, the data have been flagged as QL4 and should be used with caution. |
| QL3 | 11/6/17 | 12/18/17 | 11/6/17-12/18/17: On-station aerated DI readings indicate that the DO sensor had a significant offset of approximately 12.14% during this time period. The data have been corrected for this offset. Corrections should be considered approximate. Due to the level of offset that has been corrected for, data should be used with caution. |
| QL3 | 8/28/17 | 11/6/17 | 8/28/17-11/6/17: On-station aerated DI readings indicate that there was additional drift from ~8.7% to a ~12.14% negative offset during this time period. Data have been corrected for linear drift between these offset levels during this time period. Corrections should be considered approximate and preliminary and do not address any attenuation of the signal. Data should be used with caution. A final assessment of sensor offset & performance will be made when the sensor is recovered and evaluated. |
| QL3 | 2/7/17 | 8/28/17 | 2/7/17-8/28/1/17: On-station aerated DI readings fluctuated a bit but generally indicate a stable offset averaging 8.7% during this time period. The dissolved oxygen data were corrected for drift based on these DI readings. The correction for drift should be considered approximate and the data have been flagged as QL3. |
| QL3 | 9/20/16 | 2/7/17 | 9/20/16 – 2/7/17: On-station DI readings and comparison to data from SATURN-01 suggest that the sensor began to drift/foul after 9/20/16 to an estimated 7% offset on 9/27/16. Between then and 2/7/17 the sensor appears to have continued to drifted to an offset of approximately 9.7%. An estimate of drift was determined by a linear fit of the on-station DI data between 9/27/16 & 1/23/17. All station DI readings fall within 0-2.5% of this fit (with the exception of a single measurement). The data were corrected for drift based on these data. It should be noted that while the station DI readings suggest drift, comparison with the data from SATURN-01 does not. The correction for drift should be considered approximate and the data have been flagged as QL3. |
| QL1 | 8/30/16 10:00 | 9/20/16 | 8/30/16 10:00 – 9/20/16: The DO sensor deployed at SATURN-03 on 8/30/16 was checked in aerated DI prior to deployment and was found to be reading within manufacturer specifications. On-station DI readings following deployment along with comparisons to data from SATURN-01 indicate that there was no calibration drift or fouling during this time. Data during this time period have been flagged as good. |
| QL4 | 8/15/16 | 8/30/16 10:00 | 8/15/16 – 8/30/16: On-station readings of aerated DI show that the offset for this sensor remained stable at around 5.5% until 8/15/16 after which it appears that the sensor began to foul. The sensor was replaced with a sensor with a verified calibration on 8/30/16. The shift in data between the old and new sensor deployments, in addition to the station DI readings indicate that the sensor was reading approximately 18% low at the point of recovery. A correction for drift from 5.5% offset on 8/15/16 to an 18% offset on 8/30/16 was applied to the data. Due to high extent of offset/fouling the data during this time period have been flagged as poor (QL4) and should be used with caution. |
| QL2 | 10/31/15 | 8/15/16 | 10/31/15 – 8/15/16: prior to re-deployment on 10/31/15 the SATURN-03 D.O. sensor was reading slightly low (96.5% in 100% aerated DI). On-station readings of aerated DI and comparison with data from the recently deployed and checked sensor at SATURN-01 in May show that the calibration offset remained stable at around 5.5% through ~8/15/16. |
| QL3 | 9/1/15 12:47 | 10/30/15 | 9/1/15 – 10/30/15: A post deployment sensor check found the sensor to be reading ~85% in 100% aerated DI. Routine on-station aerated DI readings, along with comparisons with near-station DO sensor readings from a ship-board flow through system indicate that the drift was linear and onset began on 9/1/15 prior to which the sensor offset had remained stable at ~4% for several months. A correction for linear drift of the sensor between a 4.3% offset on 9/1/15 and a 15% offset on 10/30/15 has been applied to the data. Caution should be used particularly with data toward the end of this time period due to the extensive drift/fouling of the sensor. |
| QL2 | 4/16/15 | 9/1/15 12:47 | 4/16/15 – 9/1/15 12:47: The on-station aerated DI readings, along with comparisons with near-station DO sensor readings from CTD casts and a ship-board flow through system indicate that the sensor offset remained stable through August. A correction for a stable offset of ~4.3% has been applied to the data between 4/16/15 & 9/1/15. |
| QL2 | 4/3/15 10:00 | 4/16/15 | 4/3/15 10:00 – 4/16/15: The sensor at SATURN-03 was replaced on 4/3/15. The new sensor was checked prior to deployment and was reading within manufacturer specifications. The on-station aerated DI readings, along with comparisons with near-station DO sensor readings from CTD casts and a ship-board flow through system indicate that the sensor drifted down ~4-5% within the first couple of weeks of deployment, after which the offset remained stable for several months. A correction for linear drift during the first two weeks followed by a stable offset of ~4.3% has been applied to the data. |
| QL2 | 11/8/14 | 4/3/15 09:00 | 11/8/14 – 4/3/15 09:00: The sensor was recovered and tested on 11/8/14. After cleaning it was reading 96.6% in 100% aerated DI water prior to re-deployment. The sensor was recovered and tested again on 4/4/15. The sensor reading was 94.74% in 100% aerated DI at this time, indicating the sensor drifted slightly over the course of the deployment. The on-station aerated DI readings, along with comparisons with near-station DO sensor readings from a ship-board flow through system support linear interpretation of the sensor drift. A correction has been applied to the data based on linear drift between the pre- and post-deployment sensor offsets. |
| QL3 | 2/20/14 | 11/8/14 | 2/20/14 -11/8/14: The sensor was recovered and tested on 2/20/14. After cleaning it was reading within manufacturer specifications (98.25% in 100% aerated DI water) and re-deployed. The sensor was recovered and tested again on 11/8/14. The sensor reading was 92.7% in 100% aerated DI indicating the sensor drifted approximately 7% over the course of the deployment. The on-station readings support linear interpretation of the sensor drift , although indicate that the sensor may have been reading from 0.5% to 3% lower than is suggested by the sensor cross-checks. See supporting document s3do04 in the DO QA/QC archive for details of the correction. |
| QL3 | 5/31/13 | 2/20/14 | 5/31/13 – 2/20/14: The sensor was recalibrated by the manufacturer on 5/15/13 just prior to deployment on 5/31. The sensor was checked in 100% aerated fresh water prior to and following deployment. The post-deployment check showed the sensor to be reading 91.15% +/- 0.12% in the aerated DI. Frequent on-station aerated DI readings and data from near-station CTD casts show that the sensor drift was linear. The data have been corrected for linear drift, using the pre and post deployment checkout readings in 100% aerated DI. See supporting document s3do03 in the DO QA/QC archive for details of the correction. |
| QL3 | 4/9/13 | 5/31/13 | 4/9/13 – 5/31/13: 4/9/13 – 5/31/13: A calibration check on 4/9/13 found this sensor to be reading approximately 3.1% low after sensor cleaning. The post-deployment check found that the sensor was reading approximately 6.6% low as recovered and 5.9% low after cleaning. Because the sensor offset (due to a combination of drift and fouling) exceeded 5% during this time period the calibration has been flagged as QL3. Note that the calibration checks throughout this sensor’s deployment indicate that the calibration drift was linear and a correction has been applied to the data between 12/18/12 & 5/31/13. See document s3_do02 in the DO QA/QC archive for details of the correction. |
| QL2 | 1/23/13 | 4/9/13 | A mid-deployment calibration check on 1/23/13 found this sensor to be reading within 2% of three freshly calibrated sensors. Another calibration evaluation on 4/8/13 found the sensor to be reading approximately 3.6% low before cleaning and approximately 3.1% low after cleaning. The calibration quality during this period has been flagged as QL2 because it is reading only slightly outside of manufacturer specifications (+/- 2%). Note that the calibration checks throughout this sensor’s deployment indicate that the calibration drift was linear and a correction has been applied to the data between 12/18/12 & 5/31/13. See document s3_do02 in the DO QA/QC archive for details of the correction. |
| QL1 | 12/17/12 | 1/23/13 | 12/17/12 – 1/23/13: A pre-deployment check found the sensor readings to be reading within 3% of a freshly calibrated sensor and a hand-held YSI optical DO sensor. The sensor was recovered and tested against 3 newly calibrated sensors and was found to be reading within 2%. Note that the calibration checks throughout this sensor’s deployment indicate that the calibration drift was linear and a correction has been applied to the data between 12/18/12 & 5/31/13. See document s3_do02 in the DO QA/QC archive for details of the correction. |
| QL3 | 6/18/12 | 12/13/12 | 6/18/12 – 12/13/12: The sensor was freshly calibrated by SeaBird inc. and a pre-deployment check found the sensor readings to be in agreement with 4 other newly calibrated sensors. The sensor was recovered on 12/13/12 and a calibration evaluation on 12/13/12 found the sensor to be reading approximately 7% low relative to a sensor that had been freshly calibrated by seabird. A correction assuming linear drift beginning on 6/18/12 to a final 7% drift on 12/13/12 has been applied to the data. This correction is approximate and data during this time period should be used with caution. |
| QL2 | 2/9/12 | 6/18/12 | The sensor was recovered for a calibration check in early February 2012. After cleaning, the sensor response was approximately 4.5% low against a YSI handheld optode and a newly calibrated SBE43 which was deployed to SATURN-01. The sensor was recovered for a calibration check on 6/18/12 where it read 4.5% low compared to 5 newly calibrated sensors, indicating that it was stable during this time period and reading ~4.5% low. A correction for this offset has been applied to the data. |
| QL3 | 10/13/11 | 2/7/12 | The sensor calibration was verified with a mid-deployment check on 10/13/11. On 2/6/12 the sensor was recovered for another calibration check. As recovered, the sensor read approximately 11% low against a newly calibrated SBE DO sensor. Oxygen percent saturation between Saturn03 and Saturn04 were in close agreement during the beginning of this time period but diverged, with Saturn03 values dropping relative to Saturn04, in early to mid December. This divergence likely represents the onset of the sensor drift, however this cannot be verified. A correction assuming linear beginning on 12/10/11 to a final ~10% drift on 2/7/11 has been applied to the data. This correction is approximate and data during this time period should be used with caution. |
| QL1 | 9/23/11 | 10/13/11 | The DO sensor was newly calibrated on September 14, 2011. Calibration checks performed prior to deployment on 9/22/11 and then again on 10/13/11 verified the calibration remained good throughout this time period. |
| QL3 | 7/12/11 | 9/23/11 | After recovery from Saturn03 on 9/22/11, the DO sensor calibration was found to be ~9% low when checked against 2 newly calibrated SBE43 sensors. There are no data to determine the onset and progression of this fouling/drift. A correction assuming linear drift from no dirft at the point of deployment to 9% drift at the point of recovery has been applied to the data. This correction is approximate and data during this period should be used with caution. |
| QL1 | 4/25/11 | 7/12/11 | The sensor was checked against a newly calibrated SBE43 and a YSI optode on 4/25/11 and an in-situ sensor check on 7/12/11 using the YSI optode verified the sensor calibration remained good until this date. |
| QL1 | 3/3/2011 14:00 | 4/4/11 | The DO sensor was newly calibrated by SBE in February, 2011. The calibration was verified by a calibration check prior to deployment against a YSI hand-held optode and checked again against a newly calibrated SBE43 and the YSI optode on 4/25/11 showing that the calibration remained good during this time. |
| QL3 | 6/13/10 0:00 | 3/3/11 14:00 | The DO sensor at Saturn-03 was reading approximately 18% low compared to independent in-situ measurements using an YSI hand-held optode on July 22, 2010 and on August 26, 2010. After recovering this sensor from the field, a final calibration check on 3/3/11 against a newly calibrated SBE43 sensor and the YSI optode measured the same offset as the two prior in-situ checks, indicating sensor stability. A correction for the offset was applied to the raw data following SBE Application note 64-2. It is important to note, however, that this type of calibration correction was developed for use with independent measurements made by Winkler titrations. Following the deployment, the sensor was returned to the manufacturer where the sensor membrane was found to have a slower than acceptable response time. According to SeaBird Electronics, the slower response time should not be a problem for our data because it was not deployed in a profiling application. However, because the manufacturer’s calibration has been adjusted based on optode measurements and because of the membrane issues, data from this deployment should be considered suspect and used with caution. Link to correction details |
| 10/23/19 – 7/13/20: The dissolved oxygen sensor at SATURN-03 was replaced on 10/23/19: The previous sensor check showed the sensor to be reading 100% (in 100% aerated DI water). This sensor began drifting following deployment and corrections for this drift have been made based on in-situ DI readings. The drift reached approximately 4% on 2/10/20 and then 7% on March 23, 2020, after which drift greatly accelerated. Based on the extent and speed of drift, the drift-corrected data prior to 2/10/20 have been flagged as QL2; the data between 2/10/20 and 3/23/20 have been flagged as QL3. While the data between 3/23/20 and 5/15/20 have been corrected, these data should be used with caution and have been flagged as poor (QL4). |