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Managing Real-Time Oceanographic QC

Mark Bushnell,
Technical Coordinator,
NOAA/U.S. Integrated Ocean Observing System/QARTOD

In the old days, we deployed instruments in the ocean and returned a year later, hoping they had worked, we could find them, and the data were recoverable. We hoarded the data like treasure until the last publication had been extracted.

Since then, dramatic improvements have occurred in sensor technology, data communications, batteries and biofouling prevention. We’re now awash in real-time data that meet many needs. But, how can we know the quality of the data?

In 2003, NOAA’s National Data Buoy Center hosted a grass-roots meeting to discuss measuring and reporting data quality. Seventy participants named the event “Quality Assurance of Real-Time Oceanographic Data” (QARTOD) and adopted its first law: Every real-time observation distributed to the ocean community must be accompanied by a quality descriptor. After meetings spread over six years, participants had addressed quality control (QC) of in-situ wave and current observations, but there was no program to officially adopt the recommendations.

In 2012, Capt. Ray Toll (U.S. Navy, retired) proposed the QARTOD project to the U.S. Integrated Ocean Observing System (IOOS) Program Office, where it was accepted. U.S. IOOS and a QARTOD board of advisors, comprised of oceanographic experts from the private and public sector, have established a well-honed process to ensure the development, vetting and formal adoption of QC manuals. During this process, a manual is distributed nationally and internationally to subject matter experts from U.S. government agencies, academic and research institutions, manufacturers of the sensors/systems, and data consumers, all of which have the opportunity to provide feedback. A final manual is truly a reflection of community input but is also a living document.

The need for real-time QC is broadly accepted by the ocean observing community. Critical decisions are made based upon the data, so data providers (operators) and users expect verified observations. Examples of data application include water levels used to compute vessel under-keel clearance, current observations supporting search and rescue, optical observations used to regulate offshore dredge materials disposal, and wave thresholds controlling coastal engineering projects. The QARTOD project brings standardized tests for each variable, and the 11 U.S. IOOS Regional Associations must have plans in place to adopt these tests to be certified as a Regional Information Coordination Entity.

The QARTOD manuals focus on real-time data and the need to automate QC to the maximum extent possible—while recognizing the value of skilled operator oversight. In most cases, each new data point must be evaluated, flagged and disseminated immediately without the benefit of a subsequent observation in space or time. Although the purpose of the manuals is not to instruct operators on the proper sensor selection, calibration technique or other quality assurance issues, many best practices critical for accurate data are addressed in appendices. Manuals addressing waves, currents, dissolved oxygen, temperature and salinity, water levels, winds, ocean optics, and dissolved nutrients are posted at ioos.noaa.gov/qartod, as well as a document describing the data flagging scheme adopted by IOOS.

Legally defensible, real-time data in the public domain requires real-time quality control. Perhaps the most important outcome of QARTOD is the example it can provide to emerging operational observations, such as pH/ocean acidification, harmful algal blooms, or whatever an ice-free Arctic may bring. As we expand the use of resources provided by our oceans, these manuals guide the future QC process.

The U.S. IOOS Program Office appreciates the assistance provided by contributors and reviewers. If you are interested in being involved in the QARTOD project, please email mark.bushnell@noaa.gov.

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