title: Robust sensor for extended autonomous measurements of surface ocean dissolved inorganic carbon.
abstract: Ocean carbon monitoring efforts have increased dramatically in the past few decades in response to the need for better marine carbon cycle characterization. Autonomous pH and carbon dioxide (CO2) sensors capable of yearlong deployments are now commercially available; however, due to their strong covariance, this is the least desirable pair of carbonate system parameters to measure for high-quality, in situ, carbon-cycle studies. To expand the number of tools available for autonomous carbonate system observations, we have developed a robust surface ocean dissolved inorganic carbon (DIC) sensor capable of extended (>year) field deployments with a laboratory determined uncertainty of ±5 μmol kg(-1). Results from the first two field tests of this prototype sensor indicate that measurements of DIC are ∼90% more accurate than estimates of DIC calculated from contemporaneous and collocated measurements of pH and CO2. The improved accuracy from directly measuring DIC gives rise to new opportunities for quantitative, autonomous carbon-cycle studies.
authors.affiliation: †University of Washington, School of Oceanography, Box 357940, Seattle, Washington 98105, United States.
authors.forename: Andrea J
authors.initials: AJ
authors.lastname: Fassbender
authors.affiliation: ‡National Oceanic and Atmospheric Administration, Pacific Marine Environmental Laboratory, Seattle, Washington 98115, United States.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Sabine
authors.affiliation: ‡National Oceanic and Atmospheric Administration, Pacific Marine Environmental Laboratory, Seattle, Washington 98115, United States.
authors.forename: Noah
authors.initials: N
authors.lastname: Lawrence-Slavas
authors.affiliation: §University of Hawai'i at Ma̅noa, School of Ocean and Earth Science and Technology, Honolulu, Hawaii 96822, United States.
authors.forename: Eric H
authors.initials: EH
authors.lastname: De Carlo
authors.affiliation: ‡National Oceanic and Atmospheric Administration, Pacific Marine Environmental Laboratory, Seattle, Washington 98115, United States.
authors.forename: Christian
authors.initials: C
authors.lastname: Meinig
authors.affiliation: ‡National Oceanic and Atmospheric Administration, Pacific Marine Environmental Laboratory, Seattle, Washington 98115, United States.
authors.forename: Stacy
authors.initials: S
authors.lastname: Maenner Jones
mesh_terms: D002244:Carbon / Q000032:analysis*; D004784:Environmental Monitoring / Q000295:instrumentation* / Q000379:methods*; D006254:Hawaii; D009792:Oceans and Seas; D054712:Salinity; D013499:Surface Properties; D014861:Washington
chemical_list: D002244:Carbon