dc.contributor.author | Gilbert, S. | |
dc.contributor.author | Gundersen, K. | |
dc.contributor.author | Johengen, T. | |
dc.contributor.author | McKissack, T. | |
dc.contributor.author | McIntyre, M. | |
dc.contributor.author | Pinchuk, A. | |
dc.contributor.author | Purcell, H. | |
dc.contributor.author | Robertson, C. | |
dc.contributor.author | Schar, D. | |
dc.contributor.author | Smith, G.J. | |
dc.contributor.author | Tamburri, M. | |
dc.contributor.author | Wells, D. | |
dc.date.accessioned | 2019-01-21T13:15:10Z | |
dc.date.available | 2019-01-21T13:15:10Z | |
dc.date.issued | 2008 | |
dc.identifier.citation | Gilbert, S.; Gundersen, K.; Johengen, T.; McKissack, T.; McIntyre, M.; Pinchuk, A.; Purcell, H.; Robertson, C.; Schar, D.; Smith, G.J.; Tamburri, M. and Wells, D. (2008) Performance Verification Statement for the Aanderaa Data Instruments’ 4319 B Conductivity Sensor. Solomons, MD, Alliance for Coastal Technologies, 62pp. (ACT01-09). DOI: http://dx.doi.org/10.25607/OBP-327 | en_US |
dc.identifier.uri | http://hdl.handle.net/11329/770 | |
dc.identifier.uri | http://dx.doi.org/10.25607/OBP-327 | |
dc.description.abstract | Instrument performance verification is necessary so that effective existing technologies can be
recognized, and so that promising new technologies can become available to support coastal science,
resource management, and ocean observing systems. The Alliance for Coastal Technologies (ACT) has
therefore completed an evaluation of commercially available in situ salinity sensors. While the sensors
evaluated have many potential applications, the focus of this Performance Verification was on nearshore
moored and profiled deployments and at a performance resolution of between 0.1 – 0.01 salinity units.
In this Verification Statement, we present the performance results of the Aanderaa Data
Instruments (AADI) 4319 B conductivity sensor evaluated in the laboratory and under diverse
environmental conditions in moored and profiling field tests. A total of one laboratory site and five
different field sites were used for testing, including tropical coral reef, high turbidity estuary, sub-tropical
and sub-arctic coastal ocean, and freshwater riverine environments. Quality assurance (QA) oversight of
the verification was provided by ACT QA specialists, who conducted technical systems audits and a data
quality audit of the test data.
In the lab tests, the AADI 4319 B sensor exhibited a strong linear response when exposed to 15
different test conditions covering five salinities ranging from 7 – 34 psu, each at three temperatures
2
ranging from 6 - 32 oC with R >0.9999, SE = 0.0337 and slope = 0.998. The overall mean and
variance of the absolute difference between instrument measured salinity and reference sample salinity
for all treatments was -0.0244 ±0.0369 psu. When examined independently, the mean of the offsets for
the conductivity and temperature sensors were -0.0468 ±0.0454 mS/cm and -0.0146 ±0.0144 oC.
Across all five field deployments, the range of salinity tested against was 0.14 – 36.97. The
corresponding conductivity and temperatures ranges for the tests were 0.27 – 61.69 mS cm-1 and 10.75 –
31.14 oC, respectively. Extensive and rapid biofouling at the FL and GA test sites severely impacted
instrument performance within approximately one week. For the HI test site instrument performance was
stable for about three weeks before significantly impacted by fouling. The initial relative accuracy of
instrument measured salinity during the first few days of deployment period was 0.005, 0.013, -0.054, and
-0.034 psu for FL, GA, HI, and MI, respectively. The variability in response was too large in AK to
determine any initial offset. Essentially all of the variability and measurement error was traced to the
performance of the conductivity cell. The temperature sensor was quite accurate and stable throughout all
of the deployments. The average offset of the measured temperature relative to our calibrated reference
temperature logger was -0.0098, 0.0075, -0.0015, 0.0039, and -0.0022 oC for FL, GA, HI, MI, and AK,
respectively. When instrument response for the first 14 days of deployment was compared together for
2
all five field sites, a fairly consistent and linear performance response was observed with R = 0.994, SE
= 1.067 and slope = 0.984
Performance checks were completed prior to field deployment and again at the end of the
deployment, after instruments were thoroughly cleaned of fouling, to evaluate potential calibration drift
versus biofouling impacts. On several occasions results of these tests were compromised, most likely
because of entrainment of air bubbles in the conductivity cell. In general, there was no strong evidence
for calibration drift during the period of deployment and the test confirmed that the deterioration of
instrument performance during the field deployments was due to biofouling.
During this evaluation, no problems were encountered with the provided software, set-up
functions, or data extraction at any of the test sites. One hundred percent of the data was recovered
from the instrument and no outlier values were observed for all laboratory tests, all field deployment tests,
and all tank exposure tests. Lastly, a check on the instruments time clocks at the beginning and end of
field deployments showed differences of between minus 5 and plus 31 seconds among test sites. We
encourage readers to review the entire document for a comprehensive understanding of instrument
performance | en_US |
dc.language.iso | en | en_US |
dc.publisher | Alliance for Coastal Technologies (ACT) | en_US |
dc.relation.ispartofseries | ACT VS; 01-09 | |
dc.rights | CC0 1.0 Universal | * |
dc.rights.uri | http://creativecommons.org/publicdomain/zero/1.0/ | * |
dc.title | Performance Verification Statement for the Aanderaa Data Instruments’ 4319 B Conductivity Sensor. | en_US |
dc.type | Report | en_US |
dc.description.status | Published | en_US |
dc.format.pages | 62pp. | en_US |
dc.description.refereed | Refereed | en_US |
dc.publisher.place | Solomons, MD | en_US |
dc.subject.parameterDiscipline | Biogeochemistry | en_US |
dc.description.currentstatus | Current | en_US |
dc.description.eov | Sea surface salinity | en_US |
dc.description.eov | Subsurface salinity | |
dc.description.bptype | Best Practice | en_US |
dc.description.bptype | Standard Operating Procedure | en_US |
obps.contact.contactemail | info@act-us.info | |
obps.contact.contactemail | Johengen@umich.edu | |
obps.resourceurl.publisher | http://www.act-us.info/evaluations.php | en_US |