Evolving and sustaining ocean best practices and standards for the next decade

The oceans play a key role in global issues such as climate change, food security, and human health. Given their vast dimensions and internal complexity, efficient monitoring and predicting of the planet's ocean must be a collaborative effort of both regional and global scale. A first and foremost requirement for such collaborative ocean observing is the need to follow well-defined and reproducible methods across activities: from strategies for structuring observing systems, sensor deployment and usage, and the generation of data and information products, to ethical and governance aspects when executing ocean observing. To meet the urgent, planet-wide challenges we face, methods across all aspects of ocean observing should be broadly adopted by the ocean community and, where appropriate, should evolve into "Ocean Best Practices." While many groups have created best practices, they are scattered across the Web or buried in local repositories and many have yet to be digitized. To reduce this fragmentation, we introduce a new open access, permanent, digital repository of best practices documentation (oceanbestpractices.org) that is part of the Ocean Best Practices System (OBPS). The new OBPS provides an opportunity space for the centralized and coordinated improvement of ocean observing methods. The OBPS repository employs user-friendly software to significantly improve discovery and access to methods. The software includes advanced semantic technologies for search capabilities to enhance repository operations. In addition to the repository, the OBPS also includes a peer reviewed journal research topic, a forum for community discussion and a training activity for use of best practices. Together, these components serve to realize a core objective of the OBPS, which is to enable the ocean community to create superior methods for every activity in ocean observing from research to operations to applications that are agreed upon and broadly adopted across communities. Using selected ocean observing examples, we show how the OBPS supports this objective. This paper lays out a future vision of ocean best practices and how OBPS will contribute to improving ocean observing in the decade to come

Biological and physical controls on surface gas distributions along the Antarctic continental shelf

We present measurements of pCO2, O2, biological oxygen saturation (ΔO2/Ar) and N2 saturation in surface waters of the Antarctic continental shelf during austral summer, 2010–2011. pCO2 and ΔO2/Ar exhibited large spatial gradients and co-varied strongly with Chla. However, differential gas exchange led to an uncoupling of biological O2 accumulation and dissolved inorganic carbon drawdown. Computed sea-air CO2 fluxes significantly exceeded regional climatological values, suggesting that CO2 sink along the Southern Ocean continental shelf may be currently underestimated. Whereas N2 was mostly supersaturated in surface waters, atmospheric processes and mixed layer entrainment resulted in super-saturation and under-saturation of mixed layer O2. Net community production derived from entrainment-corrected surface ΔO2/Ar data showed good coherence with independent estimates based on seasonal mixed layer DIC deficits, with the highest values (~200 mmol O2 m-2 d-1) observed in frontal mixing zones and stratified regions of sea-ice melt. Our results demonstrate the utility of various gas tracers in examining the impact of physical and biological forcing on surface water biogeochemistry in oceanographic complex waters of the Antarctic continental shelf

GLODAPv2.2020 – the second update of GLODAPv2

The Global Ocean Data Analysis Project (GLODAP) is a synthesis effort providing regular compilations of surface to bottom ocean biogeochemical data, with an emphasis on seawater inorganic carbon chemistry and related variables determined through chemical analysis of water samples. GLODAPv2.2020 is an update of the previous version, GLODAPv2.2019. The major changes are: data from 106 more cruises added, extension of time coverage until 2019, and the inclusion of available discrete fugacity of CO2 (fCO2) values in the merged product files. GLODAPv2.2020 includes measurements from more than 1.2 million water samples from the global oceans collected on 946 cruises. The data for the 12 GLODAP core variables (salinity, oxygen, nitrate, silicate, phosphate, dissolved inorganic carbon, total alkalinity, pH, CFC-11, CFC-12, CFC-113, and CCl4) have undergone extensive quality control, especially systematic evaluation of bias. The data are available in two formats: (i) as submitted by the data originator but updated to WOCE exchange format and (ii) as a merged data product with adjustments applied to minimize bias. These adjustments were derived by comparing the data from the 106 new cruises with the data from the 840 quality-controlled cruises of the GLODAPv2.2019 data product. They correct for errors related to measurement, calibration, and data handling practices, while taking into account any known or likely time trends or variations in the variables evaluated. The compiled and adjusted data product is believed to be consistent to better than 0.005 in salinity, 1 % in oxygen, 2 % in nitrate, 2 % in silicate, 2 % in phosphate, 4 μmol kg−1 in dissolved inorganic carbon, 4 μmol kg−1 in total alkalinity, 0.01–0.02, depending on region, in pH, and 5 % in the halogenated transient tracers. The other variables included in the compilation, such as isotopic tracers and discrete fCO2 were not subjected to bias comparison or adjustments. The original data, their documentation and doi codes are available at the Ocean Carbon Data System of NOAA NCEI (https://www.nodc.noaa.gov/ocads/oceans/GLODAPv2_2020/, last access: 22 June 2020). This site also provides access to the merged data product, which is provided as a single global file and as four regional ones – the Arctic, Atlantic, Indian, and Pacific oceans – under https://doi.org/10.25921/2c8h-sa89 (Olsen et al., 2020). The bias corrected product files also include significant ancillary and approximated data. These were obtained by interpolation of, or calculation from, measured data. This living data update documents the GLODAPv2.2020 methods and provides a broad overview of the secondary quality control procedures and results

GLODAPv2.2019 – an update of GLODAPv2

The Global Ocean Data Analysis Project (GLODAP) is asynthesis effort providing regular compilations of surface to bottom oceanbiogeochemical data, with an emphasis on seawater inorganic carbon chemistryand related variables determined through chemical analysis of water samples.This update of GLODAPv2, v2.2019, adds data from 116 cruises to the previousversion, extending its coverage in time from 2013 to 2017, while also addingsome data from prior years. GLODAPv2.2019 includes measurements from morethan 1.1 million water samples from the global oceans collected on 840cruises. The data for the 12 GLODAP core variables (salinity, oxygen,nitrate, silicate, phosphate, dissolved inorganic carbon, total alkalinity,pH, CFC-11, CFC-12, CFC-113, and CCl4) have undergone extensive qualitycontrol, especially systematic evaluation of bias. The data are available intwo formats: (i) as submitted by the data originator but updated to WOCEexchange format and (ii) as a merged data product with adjustments appliedto minimize bias. These adjustments were derived by comparing the data fromthe 116 new cruises with the data from the 724 quality-controlled cruises ofthe GLODAPv2 data product. They correct for errors related to measurement,calibration, and data handling practices, taking into account any known orlikely time trends or variations. The compiled and adjusted data product isbelieved to be consistent to better than 0.005 in salinity, 1 % in oxygen,2 % in nitrate, 2 % in silicate, 2 % in phosphate, 4 µmol kg−1 in dissolved inorganic carbon, 4 µmol kg−1 in totalalkalinity, 0.01–0.02 in pH, and 5 % in the halogenated transienttracers. The compilation also includes data for several other variables,such as isotopic tracers. These were not subjected to bias comparison oradjustments.The original data, their documentation and DOI codes are available in theOcean Carbon Data System of NOAA NCEI(https://www.nodc.noaa.gov/ocads/oceans/GLODAPv2_2019/, last access: 17 September 2019). Thissite also provides access to the merged data product, which is provided as asingle global file and as four regional ones – the Arctic, Atlantic, Indian,and Pacific oceans – under https://doi.org/10.25921/xnme-wr20(Olsen et al., 2019). Theproduct files also include significant ancillary and approximated data.These were obtained by interpolation of, or calculation from, measured data.This paper documents the GLODAPv2.2019 methods and provides a broad overviewof the secondary quality control procedures and results