Publications

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1972
Cooper, AR, Varshney.Ak, Sarkar SK, Swift J, Yen F, Klein L.  1972.  Some aspects of the thermal history of lunar glass. Journal of the American Ceramic Society. 55:260-264.   10.1111/j.1151-2916.1972.tb11276.x   AbstractWebsite

Electron microprobe examination revealed that glassy lunar fragments had inclusions as well as boundaries between mineral glasses of different compositions. Glassy lunar spherules (40 to 60 μm in diameter) showed detectable heterogeneity less marked than that of the fragments. The room-temperature refractive indices and densities of the spherules are changed by heat-treating them at 500° to 7O0°C. The large increases (as much as 2% in density and 0.7% in index of refraction) are difficult to explain on the basis of classical glass-transition phenomena alone unless extremely rapid cooling rates are assumed. Further, the spherules darkened significantly when they were heated in air or a medium vacuum (∼10−5 mm Hg) above 625°C.

1976
Swift, JH, Aagaard K.  1976.  Upwelling near Samalga Pass. Limnology and Oceanography. 21:399-408. AbstractWebsite
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1980
Swift, JH, Aagaard K, Malmberg SA.  1980.  The contribution of the Denmark strait overflow to the deep North Atlantic. Deep-Sea Research Part a-Oceanographic Research Papers. 27:29-42.   10.1016/0198-0149(80)90070-9   AbstractWebsite

Dense water formed in the seas north of the Greenland-Scotland ridge system overflows the ridges and sinks in the North Atlantic. The overflow through Denmark Strait provides the densest component of the Northwest Atlantic Bottom Water, a principal component of the North Atlantic Deep Water. Vertical hydrographic trends in the deep northwest Atlantic differ markedly, however, from those at and north of the Denmark Strait sill. Norwegian Sea Deep Water (NSDW), the densest water mass found north of the sill, contributes less than 10% to the overflow through Denmark Strait. Instead, the principal dense component of this overflow is an intermediate water of arctic origin, at slightly under 34.9% and about 5 T.U. This water is in part formed in winter at the sea surface in the Iceland Sea. The remainder is of more northerly origin, carried southward by the East Greenland Current. Though this intermediate water mass is only slightly less dense than NSDW, its residence time (3 to 4 years) in the waters north of Iceland is an order of magnitude less than that of NSDW. Hence, the deep North Atlantic may be more sensitive to climatological and ecological perturbations than hitherto believed.

1981
Swift, JH, Aagaard K.  1981.  Seasonal transitions and water mass formation in the Iceland and Greenland seas. Deep-Sea Research Part a-Oceanographic Research Papers. 28:1107-1129.   10.1016/0198-0149(81)90050-9   AbstractWebsite

The dense waters of the Iceland and Greenland sea gyres are not simply the product of a gradual transition between cold, relatively fresh polar waters on the west and warmer, saline Atlantic water on the east, but instead constitute a unique hydrographic region, bounded by the polar and arctic fronts, which we term the arctic domain. Although deep and bottom water is the best-known water mass formed in the arctic domain, the region also produces a spectrum of dense intermediate water types in winter. Our study concentrates upon water mass formation in the Iceland Sea, where the principal winter product is an intermediate water mass nearly as cold as the deep water, but slightly less saline and therefore always lying above the deep water. The intermediate water mass produced in greatest volume in the Greenland Sea is warmer and more saline, although of nearly the same density as that produced in the Iceland Sea. The principal difference between the seasonal transitions in the Greenland and Iceland seas is that the transition in the Greenland Sea involves slightly more saline water than does that in the Iceland Sea, due to a more pronounced contribution of cooled Atlantic water. Subsequent along-isopycnal mixing of the intermediate water masses produces water which needs only to undergo a final cooling stage to be transformed into new deep and bottom water.

1983
Brewer, PG, Broecker WS, Jenkins WJ, Rhines PB, Rooth CG, Swift JH, Takahashi T, Williams RT.  1983.  A climatic freshening of the deep Atlantic north of 50°N over the past 20 years. Science. 222:1237-1239.   10.1126/science.222.4629.1237   AbstractWebsite

Observations made in summer 1981 show a significant and widespread decrease in salinity, averaging 0.02 per mil, in deep waters of the subpolar North Atlantic over the past two decades. This implies a relatively rapid response of deep water formation to climatic perturbation.

Swift, JH, Takahashi T, Livingston HD.  1983.  The contribution of the Greenland and Barents seas to the deep water of the Arctic Ocean. Journal of Geophysical Research-Oceans and Atmospheres. 88:5981-5986.   10.1029/JC088iC10p05981   AbstractWebsite

The deep waters of the Arctic Ocean are traditionally held to be fed by an influx of Norwegian Sea Deep Water (NSDW) via the northward flowing West Spitsbergen Current. Discrete sample and CTD observations obtained from the Greenland-Spitsbergen Passage in August 1981 during the Transient Tracers in the Ocean (TTO) North Atlantic expedition showed a ≈ 100-m-thick layer of modified Greenland Sea Deep Water (GSDW: colder and fresher than NSDW) at 2500 m, spreading northward along the bottom of a deep, unimpeded channel, underneath the NSDW. Since the available data indicate that Arctic Ocean Deep Water (AODW) has a higher salinity than NSDW, mixing of NSDW and GSDW can not produce AODW. Therefore, other sources, such as the peripheral arctic shelf seas, must contribute dense saline water to the Arctic Ocean. Concentrations of 137Cs and 90Sr observed in AODW are greater than those observed in GSDW and NSDW. The concentrations of these radionuclides on the Barents Sea shelf are sufficiently high and in the correct relative proportions to support this proposition.

1984
Swift, JH.  1984.  The circulation of the Denmark Strait and Iceland-Scotland overflow waters in the North Atlantic. Deep-Sea Research Part a-Oceanographic Research Papers. 31:1339-1355.   10.1016/0198-0149(84)90005-0   AbstractWebsite

The bottom waters of the northernmost northeast Atlantic are derived from a dense outflow from the Norwegian Sea through the Faeroe Bank Channel. Near-still mixing increases the salinity and lowers the dissolved oxygen content of the outflow, but when the mixed water later enters the northwest Atlantic through the Charlie-Gibbs Fracture Zone, it is freshened and oxygenated by mixing with the denser, lower-salinity overflow water from Denmark Strait. The end product contributes to a deep tongue of relatively saline, oxygen-rich water that has been traced in other studies throughout much of the World Ocean. This study traces the saline tongue from its origin in the Faeroe Bank Channels to the deep waters south of the Grand Banks. The relatively close coupling of the deep northern North Atlantic with the sea surface in the Greenland, Iceland, and Norwegian seas makes this region potentially responsive to changes introduced at the sea surface, though this study shows no significant temperature and salinity changes in the deep water over the 1957 to 1973 period emphasized in the analysis.

Swift, JH.  1984.  A recent -S Shift in the deep water of the northern North Atlantic. Climate processes and climate sensitivity. 5( Hansen JE, Takahashi T, Eds.).:39-47., Washington, D.C.: American Geophysical Union Abstract

Papers presented at the Fourth Biennial Maurice Ewing Symposium held at Palisades, NY, October 25-27, 1982 arranged under the headings: Atmosphere and ocean dynamics; Hydrologic cycle and clouds; Albedo and radiation processes; Cryospheric processes; Ice cores and glacial history; Ocean chemistry.

Swift, JH.  1984.  Review of North Atlantic source waters. North Atlantic deep water formation : proceedings of a workshop held at Lamont-Doherty Geological Observatory. NASA Publication CP-2367( Bennett T, Broecker WS, Hansen JE, Eds.).:2-4., Palisades, New York: National Aeronautics and Space Administration, Scientific and Technical Information Branch Abstract
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1985
Livingston, HD, Swift JH, Ostlund HG.  1985.  Artificial radionuclide tracer supply to the Denmark Strait overflow between 1972 and 1981. Journal of Geophysical Research-Oceans. 90:6971-6982.   10.1029/JC090iC04p06971   AbstractWebsite

Measurements of the concentrations of the artificial radionuclides 3H, 137Cs, and 90Sr in the northern Irminger Sea in 1972 and 1981 are reported. In both years, tracer measurements from this area included data from samples of the dense overflow water from the north through Denmark Strait. All three tracers were strongly correlated inversely with salinity in the dense outflows—the tracer maxima being related directly to the salinity minimum. When the tracer characteristics in the outflows in 1972 and 1981 were compared, concentrations of all in 1981 were observed to be about double the 1972 values. The individual tracer concentrations—on a decay-corrected, density-normalized basis—were higher in increasing order: 90Sr (+93%) < 3H (+115%) < 137Cs (+150%). The relatively greater increases for 3H and 137Cs were attributed to contributions of new sources of these tracers in northern surface waters: the 3H source is argued to derive from atmospheric hydrological recycling, whereas the 137Cs source is identified as the input to the Greenland and Iceland seas of advected European nuclear fuel reprocessing wastes. Both the tracer and hydrographic data are used to identify northern locations of intermediate water formation capable of supplying the observed dense overflow water characteristics. It is argued, from the time taken for the overflow water to reflect the new surface 137Cs source, that transport from the source to the overflow can be quite rapid (about 2 years).

Aagaard, K, Swift JH, Carmack EC.  1985.  Thermohaline circulation in the Arctic Mediterranean Seas. Journal of Geophysical Research-Oceans. 90:4833-4846.   10.1029/JC090iC03p04833   AbstractWebsite

The renewal of the deep North Atlantic by the various overflows of the Greenland-Scotland ridges is only one manifestation of the convective and mixing processes which occur in the various basins and shelf areas to the north: the Arctic Ocean and the Greenland, Iceland, and Norwegian seas, collectively called the Arctic Mediterranean. The traditional site of deep ventilation for these basins is the Greenland Sea, but a growing body of evidence also points to the Arctic Ocean as a major source of deep water. This deep water is relatively warm and saline, and it appears to be a mixture of dense, brine-enriched shelf water with intermediate strata in the Arctic Ocean. The deep water exits the Arctic Ocean along the Greenland slope to mix with the Greenland Sea deep water. Conversely, very cold low-salinity deep water from the Greenland Sea enters the Arctic Ocean west of Spitsbergen. Within the Arctic Ocean, the Lomonosov Ridge excludes the Greenland Sea deep water from the Canadian Basin, leaving the latter warm, saline, and rich in silica. In general, the entire deep-water sphere of the Arctic Mediterranean is constrained by the Greenland-Scotland ridges to circulate internally. Therefore it is certain of the intermediate waters formed in the Greenland and Iceland seas which ventilate the North Atlantic. These waters have a very short residence time in their formation areas and are therefore able to rapidly transmit surface-induced signals into the deep North Atlantic.

Swift, JH.  1985.  A few comments on a recent deep-water freshening. Glaciers, ice sheets, and sea level : effect of a CO2-induced climatic change. :129-138., Washington, D.C.: U.S. Dep. of Energy Abstract
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1986
Swift, JH.  1986.  The Arctic waters. The Nordic Seas. ( Hurdle BG, Ed.).:129-153., New York: Springer-Verlag Abstract

Thorough, multidisciplinary account of the physical environment of this ocean area which includes the Greenland, Barents and Norwegian seas. Includes chapters on climatology; ice cover; the physical properties of the sea ice cover; brief overview of the physical oceanography; the arctic waters; the sound-speed structure; features of fjord and ocean interaction; tide, bathymetry; seafloor topography, sediments and paleoenvironments; geophysical and geochemical signatures and plate tectonics.

1987
Ostlund, HG, Possnert G, Swift JH.  1987.  Ventilation rate of the deep Arctic Ocean from carbon 14 data. Journal of Geophysical Research-Oceans. 92:3769-3777.   10.1029/JC092iC04p03769   AbstractWebsite

Application of mass balances of 18O, tritium and salt, plus 14C data show that the deep Eurasian Basin exchanges water with the subarctic Atlantic Ocean on a time scale of 10 to 100 years, while the deep Canada Basin has an exchange time scale of about 700 years. Only small fractions, less than 10 to 15% of the deep waters, originate from the shelves. The deep Canada Basin cannot consist of fossil water from glacial time or from the latest cool climate spell, just 100 to 300 years ago.

1988
The Polarstern Shipboard Scientific Party.  1988.  Breakthrough in Arctic deep-sea research; the R/V Polarstern expedition 1987. EOS, Transactions, American Geophysical Union. 69:665,676--678., Washington, DC, United States (USA): American Geophysical Union, Washington, DC   10.1029/EO069i025p00665   AbstractWebsite

During summer 1987, the R/V Polarstern of the Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Federal Republic of Germany (FRG), succeeded in penetrating the eastern Arctic ice pack as far north as the Nansen-Gakkel Ridge in the central eastern Arctic Basin. Our northernmost location, at 86°H′N (Figure 1), was further north than any surface vessel dedicated to marine research has attained previously, although Soviet nuclear-powered ice breakers have managed to penetrate to the North Pole. Prior to this cruise, most knowledge about the eastern Arctic Basin came from remote sensing techniques, Nansen's Fram expedition during 1893–1896 [Bøggild, 1906; Gran, 1904; Nansen, 1902, 1904, 1906], Russian ice camps [Gordienko and Laktionov, 1969], the U.S. ice island camps Fram I-Fram IV, 1979–1982 [Hunkins et al, 1979; Baggeroer and Dyer, 1982; Manley et al, 1982; Kristoffersen, 1982; Kristoffersen et al, 1982; Kristoffersen and Husebye, 1985], and explorations by submarines.

Swift, JH, Koltermann KP.  1988.  The origin of Norwegian Sea Deep Water. Journal of Geophysical Research-Oceans. 93:3563-3569.   10.1029/JC093iC04p03563   AbstractWebsite

A nearly homogeneous water mass, the Norwegian Sea Deep Water, is found below 2000-m depth in the Norwegian and Lofoten basins of the Norwegian Sea. Recent observations indicate that this water is a mixture of relatively cold and fresh Greenland Sea Deep Water with warmer, saltier Eurasian Basin Deep Water from the Arctic Ocean. We have found this mixture along the western and southern periphery of the Greenland Sea, near the level where the pressure-compensated densities of the parent water masses are equal. The along-isopycnal mixing produces a remarkably uniform water mass, which can be traced only a short distance away from its entry into the Norwegian Sea through gaps in the mid-ocean ridge north of Jan Mayen Island. Direct measurements of flow through these gaps confirm motion in the proper sense to accomplish this connection.

Smethie, WM, Chipman DW, Swift JH, Koltermann KP.  1988.  Chlorofluoromethanes in the Arctic mediterranean seas: evidence for formation of bottom water in the Eurasian Basin and deep-water exchange through Fram Strait. Deep-Sea Research Part a-Oceanographic Research Papers. 35:347-369.   10.1016/0198-0149(88)90015-5   AbstractWebsite

During July–August of 1984, the polar research vessel R.V. Polarstern occupied sections of oceanographic stations in and north of Fram Strait and across the Greenland Sea (Boreas Basin) south of Fram Strait. The temperature, salinity and chlorofluoromethane (CFM) data for the Polarstern stations within the Eurasian Basin reveal two deep-water masses, Eurasian Basin Bottom Water (EBBW) which lies below the σ2 = 37.46 density surface and Eurasian Basin Deep Water (EBDW) which lies above this surface. The depth of this surface is close to the 2600 m sill depth of Fram Strait. The CFM, temperature and salinity distributions suggest that EBBW is partially composed of dense, high salinity shelf water advected into the deep Eurasian Basin, where it probably circulates around the basin in a deep cyclonic boundary current. An upper limit of about 0.1 Sv was estimated from the CFM data for the transport of pure high salinity shelf water into the Eurasian Basin below 3000 m. These data together with data collected on previous cruises to the Norwegian and Greenland seas reveal that EBDW exchanges with water masses south of Fram Strait, first flowing through Fram Strait in a narrow (<10 km) deep boundary current, then mixing with Greenland Sea Deep Water in the periphery of the Greenland Gyre to form new Norwegian Sea Deep Water (NSDW). Some of this new NSDW flows southeastward into the Norwegian Sea and a mixture of old and new NSDW flows northward on the eastern side of Fram Strait, returning to the Eurasian Basin. We estimate the volume transport of EBDW southwrd through Fram Strait to be 0.80–0.93 Sv. Volume transports between the deep Greenland and deep Norwegian seas and between the surface and deep Greenland Sea were also estimated with respective values of 0.80–0.93 Sv and 0.50 –0.52 Sv.

1989
Anderson, LG, Jones EP, Koltermann KP, Schlosser P, Swift JH, Wallace DWR.  1989.  The first oceanographic section across the Nansen Basin in the Arctic Ocean. Deep-Sea Research. 36:475-482.   10.1016/0198-0149(89)90048-4   AbstractWebsite

The first quasi-synoptic oceanographic section across a major deep basin of the Arctic Ocean reveals three different regimes: a narrow boundary current system along the northern Barents Shelf slope, a wide interior basin regime and a northern boundary current regime with several distinct cores along the Nansen-Gakkel Ridge at 86 degree N. The southern boundary current cores are marked by high oxygen concentrations, high salinities and low temperatures that indicate sources on the shelf and in Fram Strait. The northern boundary current regime contains water mass signatures that are thought to come from the Amundsen Basin as well as from Fram Strait. The Nansen Basin interior is only slowly ventilated from the boundary currents and shelves, the deep water having an age of several decades.

Smethie, WM, Swift JH.  1989.  The tritium:krypton-85 age of Denmark Strait Overflow Water and Gibbs Fracture Zone Water just south of Denmark Strait. Journal of Geophysical Research-Oceans. 94:8265-8275.   10.1029/JC094iC06p08265   AbstractWebsite

The opposite time trends of the input of tritium and 85Kr to the surface ocean produce a tritium:85Kr ratio for surface water that is a strong function of time and this ratio was used to determine the age of Denmark Strait Overflow Water (DSOW) and Gibbs Fracture Zone Water (GFZW) just south of Denmark Strait. DSOW and GFZW were identified by their temperature, salinity, oxygen, and silica characteristics in a section of stations 460 km south of Denmark Strait taken during the Transient Tracers in the Ocean/North Atlantic Study expedition in 1981. DSOW was the densest water observed in the section and there were two types, a low salinity type and a slightly higher salinity, more dense type. Both types originated from Arctic Intermediate Water (AIW) behind the Greenland-Iceland ridge. The tritium and 85Kr data reveal that the low salinity type resided behind the Greenland-Iceland ridge for about 1 year before flowing into the Irminger Sea, compared to about 15 years for the higher salinity type. The volume transport of the low salinity type of DSOW was estimated to have a lower limit of 0.8 Sv. GFZW forms in the northeastern Atlantic from a mixture of water flowing out of the Norwegian Sea at about 900 m depth and the northeastern Atlantic water into which it flows. About 70% of the tritium and 85Kr burden of GFZW comes from northeastern Atlantic water and 30% from Norwegian Sea water. The age of GFZW just south of Denmark Strait relative to its formation in the northeastern Atlantic is 7.5+4/−6.5 years which corresponds to a mean current speed of 1.6+10.1/−0.6 cm/s.

1990
The GSP Group.  1990.  Greenland Sea Project: A venture toward improved understanding of the oceans' role in climate. Eos, Transactions American Geophysical Union. 71:750-751,754-755.   10.1029/90EO00208   Abstract

The Greenland Sea is one of the few major areas where convective renewal of intermediate and deep waters contributes to world ocean ventilation. Basin-scale cyclonic circulation, boundary currents advecting waters of Atlantic and Polar origin, mixing across the fronts related to the boundary currents, wintertime heat loss to the atmosphere, ice formation and related brine release and sequences of penetrative plumes control the renewal. The scales involved range from gyrescale to small-scale and from interannual to hours. This wide range of environmental conditions provides an extreme ecosystem for which biota have evolved specific surviving strategies. In a joint effort, research groups from 11 nations are investigating both the processes and the rates of water-mass transformation and transport and are working on the food chain dynamics and the life cycles of dominant species up to the zooplankton level in a several-year program—the Greenland Sea Project (GSP).

Clarke, RA, Swift JH, Reid JL, Koltermann KP.  1990.  The formation of Greenland Sea Deep Water: double diffusion or deep convection? Deep-Sea Research Part a-Oceanographic Research Papers. 37:1385-1424.   10.1016/0198-0149(90)90135-i   AbstractWebsite

An examination of the extensive hydrographic data sets collected by C.S.S. Hudson and F.S. Meteor in the Norwegian and Greenland Seas during February–June 1982 reveals property distributions and circulation patterns broadly similar to those seen in earlier data sets. These data sets, however, reveal the even stronger role played by topography, with evidence of separate circulation patterns and separate water masses in each of the deep basins. The high precision temperature, salinity and oxygen data obtained reveals significant differences in the deep and bottom waters found in the various basins of the Norwegian and Greenland Seas.A comparison of the 1982 data set with earlier sets shows that the renewal of Greenland Sea Deep Water must have taken place sometime over the last decade; however there is no evidence that deep convective renewal of any of the deep and bottom waters in this region was taking place at the time of the observations.The large-scale density fields, however, do suggest that deep convection to the bottom is most likely to occure in the Greenland Basin due to its deep cyclonic circulation. The hypothesis that Greenland Sea Deep Water (GSDW) is formed through dipycnal mixing processes acting on the warm salty core of Atlantic Water entering the Greenland Sea is examined. θ-S correlations and oxygen concentrations suggest that the salinity maxima in the Greenland Sea are the product of at least two separate mixing processes, not the hypothesized single mixing process leading to GSDW.A simple one-dimensional mixed layer model with ice growth and decay demonstrates that convective renewal of GSDW would have occurred within the Greenland Sea had the winter been a little more severe. The new GSDW produced would have only 0.003 less salt and less than 0.04 ml 1−1 greater oxygen concentration than that already in the basin. Consequently, detection of whether new deep water has been produced following a winter cooling season could be difficult even with the best of modern accuracy.

1991
Hamann, IM, Swift JH.  1991.  A consistent inventory of water mass factors in the intermediate and deep Pacific Ocean derived from conservative tracers. Deep-Sea Research Part a-Oceanographic Research Papers. 38:S129-S169.   10.1016/S0198-0149(12)80008-2   AbstractWebsite

Estimates of the characteristics and proportional importance of water mass factors are determined by exploratory multivariate Q-mode factor analysis (QMFA) of Pacific Ocean hydrographic data from the region north of 30-degrees-S. The inter-tracer ratios between potential temperature, salinity, the calculated parameters "NO" and "PO" and silicate are used to establish a matrix of similarity coefficients between all station locations. Its rotated eigenvectors ("factors") are viewed as distinct water types of the system. On individual key density surfaces QMFA shows that the spatial distribution of relative contributions from the primary factors can be linked to known or suspected water types and their subsequent spreading. The minor factors reflect smaller perturbations of the dominating ratios. Another QMFA was done in three dimensions by combining all density layers to determine factors derived from diapycnal as well as isopycnal property gradients. Two primary factors represent the opposing vertical temperature and salinity-nutrients gradient: "a deep water melange", which concentrates in the Northeast Pacific (maximum where sigma-1 greater-than-or-equal-to 31.93), and a "subtropical thermocline" factor (maximum on sigma-theta = 25.80) centered in the subtropical gyres. The spatially uneven decrease of relative contribution from a "shallow" factor as one moves down from the upper to the lower thermocline suggests areas where the exchange with the "deeper" factor may be enhanced.

Roemmich, D, McCallister T, Swift J.  1991.  A transpacific hydrographic section along latitude 24°N: the distribution of properties in the subtropical gyre. Deep-Sea Research Part a-Oceanographic Research Papers. 38:S1-S20.   10.1016/S0198-0149(12)80002-1   AbstractWebsite

An intensively sampled transpacific hydrographic section along 24-degrees-N was completed in the spring of 1985. The data are described here in terms of the spatial distribution of properties, the distribution along isopycnal surfaces, and, where possible, the relationship of these distributions to the large-scale circulation of the Pacific Ocean. Near-surface waters of subtropical origin display a salinity maximum in mid-ocean, with lower salinity to the west due to greater rainfall and lower salinity in the east due to advection of water from the north. In the next layers down, containing waters of subpolar origin, the low salinity and high dissolved oxygen concentrations of those waters are most pronounced in the eastern ocean where the subpolar water is swept clockwise into the subtropical gyre. Differences between patterns of dissolved oxygen concentration and salinity indicate that both horizontal advection and upwelling contribute to observed distributions near the eastern boundary and that the two tracers contain independent information. In the upper kilometer, the eastern Pacific is richer in tracer signals and has steeper property gradients than the west. The deep Pacific has long been recognized to be the most uniform of the oceans. Although property gradients are small, they are significant, and it is found that on all isopycnal surfaces below the upper kilometer salinity increases and dissolved oxygen concentration decreases towards the east on basin-wide scales. These zonal gradients are weakest in the abyss, where there is a substantial net input of southern water, and strongest at mid-depth. Vertical diffusion is the likely cause of the uniformity in this pattern over so much of the deep North Pacific, with oxygen consumption in waters of greater age in the east also being a plausible contributor. With a highly sampled data set such as the 24-degrees-N transpacific section it is appropriate to ask how many stations are required to define property distributions and to estimate large-scale circulation and transport. Estimation of geostrophic transport requires high spatial resolution to detect flow near sloping topography at all depths. A 50% decimation of the 24-degrees-N station pattern yields a severe degradation in the estimation of transport.

Aagaard, K, Fahrbach E, Meincke J, Swift JH.  1991.  Saline outflow from the Arctic Ocean: Its contribution to the deep waters of the Greenland, Norwegian, and Iceland seas. Journal of Geophysical Research-Oceans. 96:20433-20441.   10.1029/91jc02013   AbstractWebsite

Since 1985 various investigators have proposed that Norwegian Sea deep water (NSDW) is formed by mixing of warm and saline deep water from the Arctic Ocean with the much colder and fresher deep water formed by convection in the Greenland Sea (GSDW). We here report on new observations which suggest significant modification and expansion of this conceptual model. We find that saline outflows from the Arctic Ocean result in several distinct intermediate and deep salinity maxima within the Greenland Sea; the southward transport of the two most saline modes is probably near 2 Sv. Mixing of GSDW and the main outflow core found over the Greenland slope, derived from about 1700 m in the Arctic Ocean, cannot by itself account for the properties of NSDW. Instead, the formation of NSDW must at least in part involve a source which in the Arctic Ocean is found below 2000 m. The mixing of various saline outflows is diapycnal. While significant NSDW production appears to occur in northern Fram Strait, large amounts of saline Arctic Ocean outflow also traverse the western Greenland Sea without mixing and enter the Iceland Sea. During the past decade, deep convection in the Greenland Sea has been greatly reduced, while deep outflow from the Arctic Ocean appears to have continued, resulting in a markedly warmer, slightly more saline, and less dense deep regime in the Greenland Sea.

1992
Meincke, J, Jonsson S, Swift JH.  1992.  Variability of convective conditions in the Greenland Sea. Hydrobiological variability in the ICES area, 1980-1989. 195( Dickson RR, Maelkki P, Radach G, Saetre R, Sissenwine MP, Meincke J, Eds.).:32-39., Copenhagen (Denmark): ICES Abstract

Recent observations and data compilations show decadal and interannual variations in the depth of wintertime convection in the Greenland Sea. In a qualitative study the fluctuations are related to changes in wind and thermohaline forcing. Changes in both wind-stress curl and sea-ice cover concur with the results from hydrographic observations indicating that no renewal of deep water has taken place during the 1980s.