http://hdl.handle.net/1957/12777 Search the Channel search http://ir.library.oregonstate.edu/jspui/simple-search http://hdl.handle.net/1957/14779 Title: Pacific ventilation of the Artic Ocean's lower halocline by upwelling and diapycnal mixing over the continental margin<br/><br/>Authors: Woodgate, Rebecca A.; Aagaard, Knut; Swift, James H.; Falkner, Kelly; Smethie, William M.<br/><br/>Abstract: Pacific winter waters, a major source of nutrients and buoyancy to the Arctic Ocean, are thought to ventilate the Arctic's lower halocline either by injection (isopycnal or penetrative) of cold saline shelf waters, or by cooling and freshening Atlantic waters upwelled onto the shelf. Although ventilation at salinity (S) > 34 psu has previously been attributed to hypersaline polynya waters, temperature, salinity, nutrient and tracer data suggest instead that much of the western Arctic's lower halocline is in fact influenced by a diapycnal mixing of Pacific winter waters (with S ~ 33.1 psu) and denser eastern Arctic halocline (Atlantic) waters, the mixing taking place possibly over the northern Chukchi shelf/slope. Estimates from observational data confirm that sufficient quantities of Atlantic water may be upwelled to mix with the inflowing Pacific waters, with volumes implying the halocline over the Chukchi Borderland region may be renewed on timescales of order a year.<br/><br/>Description: copyrighted by American Geophysical Union http://hdl.handle.net/1957/14780 Title: Quantitative considerations of dissolved barium as a tracer in the Arctic Ocean<br/><br/>Authors: Taylor, John Ryan; Falkner, Kelly; Schauer, Ursula; Meredith, Mike<br/><br/>Abstract: Dissolved barium (Ba) was measured along transects across Fram and DenmarkStraits as part of the 1998 ARK-XIV/2 Polarstern expedition. Results are combinedwith other available tracer observations to analyze water mass composition at Fram Strait. Acombination of Pacific water and Eurasian river runoff dominated (>80% and >10% of thetotal mass, respectively) the upper East Greenland Current (EGC), while the remainder ofthe section was dominated by North Atlantic water. A much smaller contribution ofPacific water to the EGC (≈50%) at Fram Strait in 1987 suggests that this component can bequite variable in time. North American river water was not detectable at Fram Strait in 1998.Presumably, the Eurasian river water we observed at Fram Strait transited eastward alongshelf within the Arctic, mixed with Pacific water in the vicinity of the East Siberian Sea,and was borne by the transpolar drift across the Arctic Ocean. In the absence ofsignificant net ice formation along the way such a pathway can be expected to produce morepronounced freshening of the EGC than when Eurasian river water mixes more directly offshelf into salty Atlantic waters and Pacific water is diverted largely through theCanadian archipelago. Existing measurements at the main Arctic gateways were used toconstruct a Ba budget for the Arctic Ocean under conditions of simultaneous mass, heat,and salt conservation. This preliminary budget is statistically consistent with the steady statehypothesis. On the Arctic basin scale, Ba appears to be conservative.<br/><br/>Description: copyrighted by American Geophysical Union http://hdl.handle.net/1957/14781 Title: Tracing Pacific water in the North Atlantic Ocean<br/><br/>Authors: Jones, E. P.; Swift, J. H.; Anderson, L. G.; Lipizer, M.; Civitarese, G.; Falkner, Kelly; Kattner, G.; McLaughlin, F.<br/><br/>Abstract: In the Arctic Ocean, Pacific source water can be distinguished from Atlantic sourcewater by nitrate-phosphate concentration relationships, with Pacific water having higherphosphate concentrations relative to those of nitrate. Furthermore, Pacific water, originallyfrom the inflow through Bering Strait, is clearly recognizable in the outflows of lowsalinitywaters from the Arctic Ocean to the northern North Atlantic Ocean through theCanadian Arctic Archipelago and through Fram Strait. In the Canadian ArcticArchipelago, we observe that almost all of the waters flowing through Lancaster and Jonessounds, most of the water in the top 100 m in Smith Sound (containing the flow throughNares Strait), and possibly all waters in Hudson Bay contain no water of Atlanticorigin. Significant amounts of Pacific water are also observed along the western coast ofBaffin Bay, along the coast of Labrador, and above the 200-m isobath of the GrandBanks. There is a clear signal of Pacific water flowing south through Fram Strait and alongthe east coast of Greenland extending at least as far south as Denmark Strait. Pacific watersignature can be seen near the east coast of Greenland at 66°N, but not in data at60°N. Temporal variability in the concentrations of Pacific water has been observed atseveral locations where multiple-year observations are available.<br/><br/>Description: copyrighted by American Geophysical Union http://hdl.handle.net/1957/14782 Title: Wind-driven transport pathways for Eurasian Arctic river discharge<br/><br/>Authors: Guay, Christopher K. H.; Falkner, Kelly; Muench, Robin D.; Mensch, Manfred; Frank, Markus; Bayer, Reinhold<br/><br/>Abstract: Distributions of temperature, salinity, and barium in near-surface waters (depth ≤ 50 m) of the Laptev Sea and adjacent areas of the Arctic Ocean are presented for the summers of 1993, 1995, and 1996. The tracer data indicate that while fluvial discharge was largely confined to the shelf region of the Laptev Sea in the summer of 1993, surface waters containing a significant fluvial component extended beyond the shelf break and over the slope and basin areas north of the Laptev Sea in the summers of 1995 and 1996. These distributions of fluvial discharge are consistent with local winds and suggest two principal pathways by which river waters can enter the central Arctic basins from the Laptev Sea. When southerly to southeasterly wind conditions prevail, river waters are transported northward beyond the shelf break and over the slope and adjacent basin areas. These waters can then enter the interior Arctic Ocean via upper layer flow in the vicinity of the Lomonosov Ridge. Under other wind conditions, river waters are steered primarily along the inner Laptev shelf and into the East Siberian Sea as part of the predominantly eastward coastal current system. These waters then appear to cross the shelf and enter the interior Arctic Ocean via upper layer flow aligned roughly along the Mendeleyev Ridge. The extent to which either pathway is favored in a given year is largely determined by local wind patterns during the summer months, when fluvial discharge is greatest and shelf waters are at the lowest salinity of their annual cycle.<br/><br/>Description: copyrighted by the American Geophysical Union