Biogeochemical (BGC) profiling floats can be used to study oceanic processes over large spatial and temporal scales. As the number of BGC float deployments continue to increase and BGC floats represent an ever-larger fraction of our BGC observing system, it will be essential that float measurements be free of bias relative to shipboard data. Biases in float data could create spurious variability or long-term changes in oxygen and other BGC float parameters that are either derived from (e.g., total carbon) or quality controlled using oxygen (e.g., pH and nitrate). Argo float oxygen data undergoes a drift correction being adjusted to ship deployment casts, to ship-based oxygen climatologies, or to float measurements of atmospheric oxygen (in-situ calibration). However, recent studies have shown the in-situ surface adjustment while good in the upper ocean, may not be fully sufficient to adjust oxygen at depth. In this study we perform a crossover comparison between the oxygen Argo dataset and a secondary quality-controlled shipboard dataset between 1450 and 2000 db. We have identified persistent negativeoxygen offsets (float minus ship) with a median of -2.1 µmol kg-1 (mean of 1.98 ± 3.93 (1 SD) μmol kg-1 and a 95% confidence interval (CI) around the mean of {-2.36 to -1.85}). These oxygen offsets translate to float parameter biases in nitrate with a median of 0.18 μmol kg-1(mean of 0.18 ± 0.59; CI95%{0.12 to 0.24}), in pH with a median of -5.57 mpH (mean of -5.92 ± 7.71; CI95%{-7.12 to -4.72}), and in DIC with a median of 3.2 μmol kg-1 (mean of 3.84 ± 6.76; CI95%{2.93 to 4.75}). To address this problem, we apply a correction scheme derived from the relationship between each float’s crossover offsets in dissolved oxygen and the corresponding float oxygen percent saturation which creates a corrected float-based oxygen synthesis product that is consistent with shipboard measurements and internally consistent among BGC float observations. We have also created a merged oxygen product containing the corrected BGC float data and shipboard observations that has been gridded to a monthly resolution with 1° x 1° bin-averaged fields at standard depth and density levels that will be useful to communities interested in ocean deoxygenation, acidification, changes to the carbon cycle, and air-sea fluxes of oxygen and carbon.  

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