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shelf-and river-derived elements to the central Arctic Ocean • The TPD is rich in dissolved organic matter (DOM), which facilitates long-range transport of trace metals that form complexes with DOM • Margin trace element fluxes may increase with future Arctic warming due to DOM release from permafrost thaw and increasing river discharge

a b s t r a c tAs the highest precision devices of celestial navigation system [1], star sensors have been getting more and more attention in recent years. In which the star image positioning and recognition is the key technology of CNS, while the extraction of stars from star maps is the first step. By the background noise, there are some error extractions when traditional methods are used, which can even lead to the failure of star map matching. To solve this problem, a denoising method based on overcomplete sparse representation is presented in this paper. This method uses the adaptive sparse decomposition of star map in the redundant dictionary to process the threshold, as a result, the reliability of star extraction is improved. The experimental results show that the correct rate of this method that extracting star after reducing background noise of star map is close to 100%.

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

The size partitioning of dissolved Fe (dFe<0.2 µm) into soluble (sFe<0.02 µm) and colloidal (0.02 µm < cFe < 0.2 µm) species was investigated at 28 stations along the GEOTRACES GA03 North Atlantic Transect. Upper ocean dFe size partitioning was highly variable with depth: 79±6% of aerosolderived surface dFe was maintained in the colloidal size fraction, while cFe disappeared completely at the deep chlorophyll maximum, presumably a result of preferential cFe biological uptake and/or scavenging. In the intermediate and deep ocean, however, dFe was evenly partitioned ~50:50% into sFe and cFe phases, which we hypothesize results from a "steady state" of dFe exchange reactions during and following remineralization including ligand exchange, sorption/desorption, and aggregation/disaggregation. There were only two exceptions to this constant partitioning in the intermediate/deep ocean. First, cFe dominated (82-96%) at and downstream of the Mid-Atlantic Ridge hydrothermal system. Also, along Line W between Woods Hole and Bermuda the dFe partitioning