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- Roquet, Fabien, et al.
(författare)
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Estimates of the Southern Ocean general circulation improved by animal-borne instruments
- 2013
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Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 40:23, s. 6176-6180
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Tidskriftsartikel (refereegranskat)abstract
- Over the last decade, several hundred seals have been equipped with conductivity-temperature-depth sensors in the Southern Ocean for both biological and physical oceanographic studies. A calibrated collection of seal-derived hydrographic data is now available, consisting of more than 165,000 profiles. The value of these hydrographic data within the existing Southern Ocean observing system is demonstrated herein by conducting two state estimation experiments, differing only in the use or not of seal data to constrain the system. Including seal-derived data substantially modifies the estimated surface mixed-layer properties and circulation patterns within and south of the Antarctic Circumpolar Current. Agreement with independent satellite observations of sea ice concentration is improved, especially along the East Antarctic shelf. Instrumented animals efficiently reduce a critical observational gap, and their contribution to monitoring polar climate variability will continue to grow as data accuracy and spatial coverage increase.
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| 2. |
- Murphy, Kathleen, 1972, et al.
(författare)
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Exploring the limits of dissolved organic matter fluorescence for determining seawater sources and ballast water exchange on the US Pacific coast
- 2013
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Ingår i: Journal of Marine Systems. - : Elsevier BV. - 0924-7963. ; 111-112, s. 157-166
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Tidskriftsartikel (refereegranskat)abstract
- To minimize the risk of biological invasions associated with commercial shipping, vessels are required to conduct ballast water exchange (BWE)≤200 nautical miles offshore when arriving in the US from foreign ports, and some states require coastal BWE≤50 miles offshore along domestic routes. Previous research suggests that the intensity of fluorescent dissolved organic matter (fDOM) can be used to verify whether BWE was implemented. This study examined seasonal and spatial variability of fDOM in Pacific rim ports and the adjacent seas, using the North American coast as a model system to test whether regional fluorescence intensity thresholds consistently distinguish port sites from coastal and oceanic sites at increasing distances from shore. Over 2000 samples from major port systems on the US Pacific coast and along offshore (perpendicular) and alongshore (parallel) transects were analyzed. Overall, humic fDOM fluorescence intensity (C3*=370/494nm) effectively discriminated port versus oceanic sites located further than 100. miles from shore, but discriminated only a subset of coastal versus oceanic sources within the northeastern Pacific. Data from additional global ports are needed to predict the frequency of false positive or false negative ballast source determinations using fDOM for foreign vessel traffic. © 2012 Elsevier B.V.
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