The GEOTRACES Intermediate Data Product 2014 (IDP2014) is the first publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2013. It consists of two parts: (1) a compilation of digital data for more than 200 trace elements and isotopes (TEls) as well as classical hydrographic parameters, and (2) the eGEOTRACES Electronic Atlas providing a strongly inter-linked on-line atlas including more than 300 section plots and 90 animated 3D scenes. The IDP2014 covers the Atlantic, Arctic, and Indian oceans, exhibiting highest data density in the Atlantic. The TEI data in the IDP2014 are quality controlled by careful assessment of intercalibration results and multi-laboratory data comparisons at cross-over stations. The digital data are provided in several formats, including ASCII spreadsheet, Excel spreadsheet, netCDF, and Ocean Data View collection. In addition to the actual data values the IDP2014 also contains data quality flags and 1-sigma data error values where available. Quality flags and error values are useful for data filtering. Metadata about data originators, analytical methods and original publications related to the data are linked to the data in an easily accessible way. The eGEOTRACES Electronic Atlas is the visual representation of the IDP2014 data providing section plots and a new kind of animated 3D scenes. The basin-wide 3D scenes allow for viewing of data from many cruises at the same time, thereby providing quick overviews of large-scale tracer distributions. In addition, the 3D scenes provide geographical and bathymetric context that is crucial for the interpretation and assessment of observed tracer plumes, as well as for making inferences about controlling processes. (C) 2015 The Authors. Published by Elsevier B.V
[1] To estimate decadal increases of anthropogenic CO 2 in the ocean, distributions of dissolved inorganic carbon (C T ) corrected by apparent oxygen utilization and salinity (nC T ANT ) were investigated along the World Ocean Circulation Experiment (WOCE Hydrographic Programme (WHP)) P6 section based on data obtained 10 years apart. Significant increases of nC T CAL were detected down to 1500 m (ffi27.5s q ) water depth, above which the Sub-Antarctic Mode Water (SAMW) and the Antarctic Intermediate Water (AAIW) are found. The decadal increases of nC T CAL on the isopycnal surfaces (26.6-26.9s q ) of SAMW were higher (5-8 mmol kg À1 ) to the east of 160°W than to the west of it, while the increases in AAIW were almost constant on the isopycnal surfaces (27.0-27.5s q ). The averaged increases of nC T CAL in SAMW and AAIW were 10 ± 3.1 and 4.1 ± 2.0 mmol kg À1 , respectively. Small but significant increases of nC T CAL and salinity-normalized C T (nC T ) were also found (approximately 3.0 and 5.0 mmol kg À1 , respectively) in abyssal waters occupying depths greater than 3500 m at longitude 180°-160°W, which correspond to Circumpolar Deep Water. Spatial differences of anthropogenic CO 2 accumulation are discussed in terms of water mass distributions. The water column inventory of increases of anthropogenic CO 2 in the South Pacific subtropical ocean was estimated to be 1.0 ± 0.4 mol m À2 yr À1 , which is almost the same as that previously reported.
The accident of the Fukushima Dai-ichi nuclear power plant in March 2011 released a large amount of radiocesium into the North Pacific Ocean. Vertical distributions of Fukushima-derived radiocesium were measured at stations along the 149°E meridian in the western North Pacific during the winter of 2012. In the subtropical region, to the south of the Kuroshio Extension, we found a subsurface radiocesium maximum at a depth of about 300 m. It is concluded that atmospheric-deposited radiocesium south of the Kuroshio Extension just after the accident had been transported not only eastward along with surface currents but also southward due to formation/subduction of subtropical mode waters within about 10 months after the accident. The total amount of decay-corrected 134Cs in the mode water was an estimated about 6 PBq corresponding to 10–60% of the total inventory of Fukushima-derived 134Cs in the North Pacific Ocean.
Using high‐quality data for dissolved inorganic carbon and related properties obtained about 10 years apart (1992/1993–2003), we examined decadal increases of anthropogenic CO2 (ΔnCTCAL) along 30°S (WHP A10 section) in the subtropical South Atlantic. Significant ΔnCTCAL was detectable down to an isopycnal surface of σθ = 27.3 (∼1000 m water depth). Averaged ΔnCTCAL in Sub‐Antarctic Mode Water (SAMW; 26.6–27.0 σθ, 350–700 m) was 6.8 ± 1.6 μmol kg−1 and that in Antarctic Intermediate Water (AAIW; 27.1–27.4 σθ, 700–1200 m) was 3.6 ± 1.4 μmol kg−1. In SAMW, ΔnCTCAL was higher by ∼7 μmol kg−1 west of 15°W than east of it, while ΔnCTCAL in AAIW did not show such a distinct east‐west difference. For deep waters, significant ΔnCTCAL was detected in Antarctic Bottom Water at depths greater than 4500 m in the Cape Basin (longitude 2°E–10°E). No significant ΔnCTCAL could be detected for North Atlantic Deep Water (NADW). We attributed ΔnCTCAL being higher west of 15°W in SAMW to differences of water mass distributions and flows. From a water column inventory, we estimated the uptake rate of anthropogenic CO2 over the decade from 1992/1993 to 2003 to be 0.6 ± 0.1 mol m−2 a−1, which is half the rate in the South Pacific (1.0 ± 0.4 mol m−2 a−1).
The Fukushima Dai-ichi Nuclear Power Plant accident in March 2011 released radiocaesium (137Cs and 134Cs) into the North Pacific Ocean. Meridional transects of the vertical distribution of radiocaesium in seawater were measured along 147 °E and 155 °E in October–November 2012, 19 months after the accident. These measurements revealed subsurface peaks in radiocaesium concentrations at locations corresponding to two mode waters, Subtropical Mode Water and Central Mode Water. Mode water is a layer of almost vertically homogeneous water found over a large geographical area. Here we show that repeated formation of mode water during the two winter seasons after the Fukushima accident and subsequent outcropping into surface water transported radiocaesium downward and southward to subtropical regions of the North Pacific. The total amount of Fukushima-derived 134Cs within Subtropical Mode Water, decay-corrected to April 2011, was estimated to be 4.2 ± 1.1 PBq in October–November 2012. This amount of 134Cs corresponds to 22–28% of the total amount of 134Cs released to the Pacific Ocean.
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