Quality control procedures and methods of the CARINA database

Tanhua, Toste; Heuven, Steven van; Key, Robert M.; Velo, A.; Olsen, Are; Schirnick, Carsten

doi:10.5194/essd-2-35-2010

Cited by 120 publications

(202 citation statements)

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“…The suggested corrections are multiplicative. The CARINA-wide threshold for considering application of corrections to nutrient data were 2% (Tanhua et al, 2010b). However, in the deep Nordic Seas, 2% corresponds to ∼ 0.3 µmol kg −1 for nitrate, ∼ 0.02 µmol kg −1 for phosphate and ∼ 0.3 µmol kg −1 for silicate.…”

Section: Resultsmentioning

confidence: 99%

“…Out of the 188 CARINA cruises, 62 are included in the CARINA-AMS, and 35 of these considered as Nordic Seas cruises. Five of these are in common with the Atlantic Ocean subset of CARINA and three of those had nutrient data (Tanhua et al, 2010b). The recommendations for these are the same for the Atlantic and Nordic Seas groups, in order to ensure consistency between the regions.…”

Section: Data Provenance and Structurementioning

confidence: 99%

“…In such cases it was far from trivial, if not impossible to extract the nitrate and nitrite concentrations. However, given that nitrite is normally only a trace constituent or absent, particularly in oxygenated deep water, we follow here the example for CARINA cruises in the Atlantic and report these data as nitrate, ignoring the possible contribution of nitrite (Tanhua et al, 2010b). Two methods were used in the secondary quality controll of the data: crossover and inversion analysis and evaluation of phosphate-nitrate (P-N) relationships, these are described in the following two sections.…”

Section: Data Provenance and Structurementioning

confidence: 99%

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Nordic Seas nutrients data in CARINA

Ólafsson

Olsen

2010

Earth Syst. Sci. Data

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Abstract.Water column data of carbon and carbon relevant hydrographic and hydrochemical parameters from 188 cruises in the Arctic, Atlantic, and Southern Ocean have been assembled and the collection merged into a new database: CARINA (CARbon IN the Atlantic). The data have been subject to rigorous quality control (QC) in order to ensure highest possible quality and consistency. The data for most of the parameters included were examined in order to quantify systematic biases in the reported values, i.e. secondary quality control. Significant biases have been corrected for in the data products, i.e. the three merged files with measured, calculated and interpolated values for each of the three CARINA regions; the Arctic Mediterranean Seas (AMS), the Atlantic (ATL) and the Southern Ocean (SO). With the adjustments, the CARINA database is consistent both internally as well as with GLODAP (Key et al., 2004) and is suitable for accurate assessments of, for example, oceanic carbon inventories and uptake rates, and for model validation. The Arctic Mediterranean Seas is the collective term for the Arctic Ocean and the Nordic Seas, and the quality control was carried out separately in these two areas. This contribution presents an account of the quality control of the nutrients (nitrate, phosphate, and silicate) data from the Nordic Seas in CARINA. Out of the 35 cruises from the Nordic Seas included in CARINA, 33 had nutrients data. The nitrate data from 4 of these appeared to be of so poor quality that they should not be used, for phosphate this number is 7 and for silicate it is 3. We also recommend that the nitrate data from 4 of the cruises should be adjusted, for phosphate and silicate only data from one cruise should be adjusted. The final data appears consistent to 5% based on evaluation of deep data. For nitrate this corresponds to 0.6 µmol kg −1 , and for phosphate and silicate it corresponds to 0.04 and 0.6 µmol kg −1 , respectively. Data coverage and parameter measuredRepository-Reference:

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Section: Resultsmentioning

confidence: 99%

Section: Data Provenance and Structurementioning

confidence: 99%

Section: Data Provenance and Structurementioning

confidence: 99%

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Nordic Seas nutrients data in CARINA

Ólafsson

Olsen

2010

Earth Syst. Sci. Data

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“…The mean profile is calculated by first interpolating the individual profiles to standard depths using a piecewise cubic hermite interpolating method that do not allow too large vertical distances between data points, and then by taking the arithmetic mean of the interpolated profiles (e.g. Tanhua et al, 2010).The parameters are salinity, temperature, oxygen, CFC-12, CFC-12 age, tritium-3 He age, CFC-12 mean age, tritium mean age, and for the cruise of 2011 also the SF 6 mean age (mean ages means TTD-derived ages). A further instrument to identify changes in circulation is the comparison of CFC-12 and SF 6 ages determined in different years but at the same location.…”

Section: Combination and Comparison Of Nine Cruisesmentioning

confidence: 99%

Changes in ventilation of the Mediterranean Sea during the past 25 year

et al. 2014

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Abstract. Significant changes in the overturning circulation of the Mediterranean Sea has been observed during the last few decades, the most prominent phenomena being the Eastern Mediterranean Transient (EMT) in the early 1990s and the Western Mediterranean Transition (WMT) during the mid-2000s. During both of these events unusually large amounts of deep water were formed, and in the case of the EMT, the deep water formation area shifted from the Adriatic to the Aegean Sea. Here we synthesize a unique collection of transient tracer (CFC-12, SF 6 and tritium) data from nine cruises conducted between 1987 and 2011 and use these data to determine temporal variability of Mediterranean ventilation. We also discuss biases and technical problems with transient tracer-based ages arising from their different input histories over time; particularly in the case of time-dependent ventilation.We observe a period of low ventilation in the deep eastern (Levantine) basin after it was ventilated by the EMT so that the age of the deep water is increasing with time. In the Ionian Sea, on the other hand, we see evidence of increased ventilation after year 2001, indicating the restarted deep water formation in the Adriatic Sea. This is also reflected in the increasing age of the Cretan Sea deep water and decreasing age of Adriatic Sea deep water since the end of the 1980s. In the western Mediterranean deep basin we see the massive input of recently ventilated waters during the WMT. This signal is not yet apparent in the Tyrrhenian Sea, where the ventilation seems to be fairly constant since the EMT. Also the western Alboran Sea does not show any temporal trends in ventilation.

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“…However, the low dynamically range of phosphate (phosphate is roughly 170 times less sensitive to remineralization than oxygen is (Anderson and Sarmiento, 1994)), the lower accuracy, and the lower frequency of phosphate measurements vs. oxygen measurements (e.g. Tanhua et al, 2010) makes this choice less attractive for observational studies.…”

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confidence: 99%

Changes in column inventories of carbon and oxygen in the Atlantic Ocean

Tanhua

2012

Biogeosciences

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Abstract. Increasing concentrations of dissolved inorganic carbon (DIC) in the interior ocean are expected as a direct consequence of increasing concentrations of CO 2 in the atmosphere. This extra DIC is often referred to as anthropogenic carbon (C ant ), and its inventory, or increase rate, in the interior ocean has previously been estimated by a multitude of observational approaches. Each of these methods is associated with hard to test assumptions since C ant cannot be directly observed. Results from a simpler concept with fewer assumptions applied to the Atlantic Ocean are reported on here using two large data collections of carbon relevant bottle data. The change in column inventory on decadal time scales, i.e. the storage rate, of DIC, respiration compensated DIC and oxygen is calculated for the Atlantic Ocean. We report storage rates and the confidence intervals of the mean trend at the 95 % level (CI), reflecting the mean trend but not considering potential biasing effects of the spatial and temporal sampling. For the whole Atlantic Ocean the mean trends for DIC and oxygen are non-zero at the 95 % confidence level: DIC: 0.86 (CI: 0.72-1.00) and oxygen: −0.24 (CI: −0.41-(−0.07)) mol m −2 yr −1 . For oxygen, the whole Atlantic trend is dominated by the subpolar North Atlantic, whereas for other regions the O 2 trends are not significant. The storage rates are similar to changes found by other studies, although with large uncertainty. For the subpolar North Atlantic the storage rates show significant temporal and regional variation of all variables. This seems to be due to variations in the prevalence of subsurface water masses with different DIC and oxygen concentrations leading to sometimes different signs of storage rates for DIC compared to published C ant estimates. This study suggest that accurate assessment of the uptake of CO 2 by the oceans will require accounting not only for processes that influence C ant but also additional processes that modify CO 2 storage.

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Quality control procedures and methods of the CARINA database

Cited by 120 publications

References 10 publications

Nordic Seas nutrients data in CARINA

Nordic Seas nutrients data in CARINA

Changes in ventilation of the Mediterranean Sea during the past 25 year

Changes in column inventories of carbon and oxygen in the Atlantic Ocean

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