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2012
Whalen, CB, Talley LD, MacKinnon JA.  2012.  Spatial and temporal variability of global ocean mixing inferred from Argo profiles. Geophysical Research Letters. 39:n/a-n/a.   10.1029/2012GL053196   AbstractWebsite

The influence of turbulent ocean mixing transcends its inherently small scales to affect large scale ocean processes including water-mass transformation, stratification maintenance, and the overturning circulation. However, the distribution of ocean mixing is not well described by sparse ship-based observations since this mixing is both spatially patchy and temporally intermittent. We use strain information from Argo float profiles in the upper 2,000 m of the ocean to generate over 400,000 estimates of the energy dissipation rate, indicative of ocean mixing. These estimates rely on numerous assumptions, and do not take the place of direct measurement methods. Temporally averaged estimates reveal clear spatial patterns in the parameterized dissipation rate and diffusivity distribution across all the oceans. They corroborate previous observations linking elevated dissipation rates to regions of rough topography. We also observe heightened estimated dissipation rates in areas of high eddy kinetic energy, as well as heightened diffusivity in high latitudes where stratification is weak. The seasonal dependence of mixing is observed in the Northwest Pacific, suggesting a wind-forced response in the upper ocean.

2011
Hartin, CA, Fine RA, Sloyan BM, Talley LD, Chereskin TK, Happell J.  2011.  Formation rates of Subantarctic mode water and Antarctic intermediate water within the South Pacific. Deep-Sea Research Part I-Oceanographic Research Papers. 58:524-534.   10.1016/j.dsr.2011.02.010   AbstractWebsite

The formation of Subantarctic Mode Water (SAMW) and Antarctic Intermediate Water (AAIW) significantly contributes to the total uptake and storage of anthropogenic gases, such as CO(2) and chlorofluorocarbons (CFCs), within the world's oceans. SAMW and AAIW formation rates in the South Pacific are quantified based on CFC-12 inventories using hydrographic data from WOCE. CLIVAR, and data collected in the austral winter of 2005. This study documents the first wintertime observations of CFC-11 and CFC-12 saturations with respect to the 2005 atmosphere in the formation region of the southeast Pacific for SAMW and AAIW. SAMW is 94% and 95% saturated for CFC-11 and CFC-12, respectively, and AAIW is 60% saturated for both CFC-11 and CFC-12. SAMW is defined from the Subantarctic Front to the equator between potential densities 26.80-27.06 kg m(-3), and AAIW is defined from the Polar Front to 20 degrees N between potential densities 27.06-27.40 kg m(-3). CFC-12 inventories are 16.0 x 10(6) moles for SAMW and 8.7 x 10(6) moles for AAIW, corresponding to formation rates of 7.3 +/- 2.1 Sv for SAMW and 5.8 +/- 1.7 Sv for AAIW circulating within the South Pacific. Inter-ocean transports of SAMW from the South Pacific to the South Atlantic are estimated to be 4.4 +/- 0.6 Sv. Thus, the total formation of SAMW in the South Pacific is approximately 11.7 +/- 2.2 Sv. These formation rates represent the average formation rates over the major period of CFC input, from 1970 to 2005. The CFC-12 inventory maps provide direct evidence for two areas of formation of SAMW, one in the southeast Pacific and one in the central Pacific. Furthermore, eddies in the central Pacific containing high CFC concentrations may contribute to SAMW and to a lesser extent AAIW formation. These CFC-derived rates provide a baseline with which to compare past and future formation rates of SAMW and AAIW. (C) 2011 Elsevier Ltd. All rights reserved.

Cerovecki, I, Talley LD, Mazloff MR.  2011.  A Comparison of Southern Ocean Air-Sea Buoyancy Flux from an Ocean State Estimate with Five Other Products. Journal of Climate. 24:6283-6306.   10.1175/2011jcli3858.1   AbstractWebsite

The authors have intercompared the following six surface buoyancy flux estimates, averaged over the years 2005-07: two reanalyses [the recent ECMWF reanalysis (ERA-Interim; hereafter ERA), and the National Centers for Environmental Prediction (NCEP)-NCAR reanalysis 1 (hereafter NCEP1)], two recent flux products developed as an improvement of NCEP1 [the flux product by Large and Yeager and the Southern Ocean State Estimate (SOSE)], and two ad hoc air sea flux estimates that are obtained by combining the NCEP1 or ERA net radiative fluxes with turbulent flux estimates using the Coupled Ocean Atmosphere Response Experiment (COARE) 3.0 bulk formulas with NCEP1 or ERA input variables. The accuracy of SOSE adjustments of NCEP1 atmospheric fields (which SOSE uses as an initial guess and a constraint) was assessed by verification that SOSE reduces the biases in the NCEP1 fluxes as diagnosed by the Working Group on Air-Sea Fluxes (Taylor), suggesting that oceanic observations may be a valuable constraint to improve atmospheric variables. Compared with NCEP1, both SOSE and Large and Yeager increase the net ocean heat loss in high latitudes, decrease ocean heat loss in the subtropical Indian Ocean, decrease net evaporation in the subtropics, and decrease net precipitation in polar latitudes. The large-scale pattern of SOSE and Large and Yeager turbulent heat flux adjustment is similar, but the magnitude of SOSE adjustments is significantly larger. Their radiative heat flux adjustments patterns differ. Turbulent heat fluxes determined by combining COARE bulk formulas with NCEP1 or ERA should not be combined with unmodified NCEP1 or ERA radiative fluxes as the net ocean heat gain poleward of 25 degrees S becomes unrealistically large. The other surface flux products (i.e., NCEP1, ERA, Large and Yeager, and SOSE) balance more closely. Overall, the statistical estimates of the differences between the various air-sea heat flux products tend lobe largest in regions with strong ocean mesoscale activity such as the Antarctic Circumpolar Current and the western boundary currents.

Talley, LD, Pickard GL, Emery WJ, Swift JH.  2011.  Descriptive physical oceanography : an introduction. :viii,555p.,60p.ofplates., Amsterdam ; Boston: Academic Press Abstract

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2010
Chereskin, TK, Talley LD, Sloyan BM.  2010.  Nonlinear vorticity balance of the Subantarctic Front in the southeast Pacific. Journal of Geophysical Research-Oceans. 115   10.1029/2009jc005611   AbstractWebsite

Direct velocity observations from shipboard and lowered acoustic Doppler current profilers are used to examine the velocity and vorticity structure of the Subantarctic Front (SAF) between the East Pacific Rise and Drake Passage from surveys made in 2005 and 2006. The SAF is characterized by meanders of horizontal wavelength approximately 250-300 km in this region of relatively smooth topography. The depth-averaged SAF jet is observed to be closely aligned with the flow at 150 m, as in an equivalent barotropic flow. The barotropic or depth-averaged vorticity exhibits a balance between advection of planetary vorticity and relative vorticity, as would be seen in a Doppler-shifted short barotropic Rossby wave in a mean flow. The implied wave speed is consistent with the observed range of current speeds. An exponential fit to the vertical structure of the current consistent with the vorticity balance suggests a vertical decay scale of about 1900 m. The vorticity balance at 150 m implies a surface divergence which must be balanced at depth by a divergence of the opposite sign. The calculation confirms the tentative conclusions of Hughes (2005) for this region, which were based on a surface climatology but indicates a larger vertical decay scale and wave speed.

Sloyan, BM, Talley LD, Chereskin TK, Fine R, Holte J.  2010.  Antarctic Intermediate Water and Subantarctic Mode Water Formation in the Southeast Pacific: The Role of Turbulent Mixing. Journal of Physical Oceanography. 40:1558-1574.   10.1175/2010jpo4114.1   AbstractWebsite

During the 2005 austral winter (late August-early October) and 2006 austral summer (February-mid-March) two intensive hydrographic surveys of the southeast Pacific sector of the Southern Ocean were completed. In this study the turbulent kinetic energy dissipation rate epsilon, diapycnal diffusivity kappa, and buoyancy flux J(b) are estimated from the CTD/O(2) and XCTD profiles for each survey. Enhanced kappa of O(10(-3) to 10(-4) m(2) s(-1)) is found near the Subantarctic Front (SAF) during both surveys. During the winter survey, enhanced kappa was also observed north of the "subduction front,'' the northern boundary of the winter deep mixed layer north of the SAF. In contrast, the summer survey found enhanced kappa across the entire region north of the SAF below the shallow seasonal mixed layer. The enhanced kappa below the mixed layer decays rapidly with depth. A number of ocean processes are considered that may provide the energy flux necessary to support the observed diffusivity. The observed buoyancy flux (4.0 x 10(-8) m(2) s(-3)) surrounding the SAF during the summer survey is comparable to the mean buoyancy flux (0.57 x 10(-8) m(2) s(-3)) associated with the change in the interior stratification between austral summer and autumn, determined from Argo profiles. The authors suggest that reduced ocean stratification during austral summer and autumn, by interior mixing, preconditions the water column for the rapid development of deep mixed layers and efficient Antarctic Intermediate Water and Subantarctic Mode Water formation during austral winter and early spring.

Cronin, MF, Bond N, Booth J, Ichikawa H, Joyce TM, Kelly K, Kubota M, Qiu B, Reason C, Rouault M, Sabine C, Saino T, Small J, Suga T, Talley LD, Thompson LA, Weller RA.  2010.  Monitoring Ocean - Atmosphere Interactions in Western Boundary Current Extensions. Proceedings of OceanObs’09: Sustained Ocean Observations and Information for Society. 2( Hall J, Harrison DE, Stammer D, Eds.).   doi:10.5270/OceanObs09.cwp.20   Abstract
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Talley, L, Fine R, Lumpkin R, Maximenko N, Morrow R.  2010.  Surface Ventilation and Circulation. Proceedings of OceanObs’09: Sustained Ocean Observations and Information for Society. 1( Hall J, Harrison DE, Stammer D, Eds.).   10.5270/OceanObs09.pp.38   Abstract
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2009
Marshall, J, Andersson A, Bates N, Dewar W, Doney S, Edson J, Ferrari R, Forget G, Fratantoni D, Gregg M, Joyce T, Kelly K, Lozier S, Lumpkin R, Maze G, Palter J, Samelson R, Silverthorne K, Skyllingstad E, Straneo F, Talley L, Thomas L, Toole J, Weller R, Climode G.  2009.  The CLIMODE FIELD CAMPAIGN Observing the Cycle of Convection and Restratification over the Gulf Stream. Bulletin of the American Meteorological Society. 90:1337-1350.   10.1175/2009bams2706.1   AbstractWebsite
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Holte, J, Talley L.  2009.  A New Algorithm for Finding Mixed Layer Depths with Applications to Argo Data and Subantarctic Mode Water Formation. Journal of Atmospheric and Oceanic Technology. 26:1920-1939.   10.1175/2009jtecho543.1   AbstractWebsite

A new hybrid method for finding the mixed layer depth (MLD) of individual ocean profiles models the general shape of each profile, searches for physical features in the profile, and calculates threshold and gradient MLDs to assemble a suite of possible MLD values. It then analyzes the patterns in the suite to select a final MLD estimate. The new algorithm is provided in online supplemental materials. Developed using profiles from all oceans, the algorithm is compared to threshold methods that use the C. de Boyer Monte gut et al. criteria and to gradient methods using 13 601 Argo profiles from the southeast Pacific and southwest Atlantic Oceans. In general, the threshold methods find deeper MLDs than the new algorithm and the gradient methods produce more anomalous MLDs than the new algorithm. When constrained to using only temperature profiles, the algorithm offers a clear improvement over the temperature threshold and gradient methods; the new temperature algorithm MLDs more closely approximate the density algorithm MLDs than the temperature threshold and gradient MLDs. The algorithm is applied to profiles from a formation region of Subantarctic Mode Water (SAMW) and Antarctic Intermediate Water (AAIW). The density algorithm finds that the deepest MLDs in this region routinely reach 500 dbar and occur north of the A. H. Orsi et al. mean Subantarctic Front in the southeastern Pacific Ocean. The deepest MLDs typically occur in August and September and are congruent with the subsurface salinity minimum, a signature of AAIW.

Macdonald, AM, Mecking S, Robbins PE, Toole JM, Johnson GC, Talley L, Cook M, Wijffels SE.  2009.  The WOCE-era 3-D Pacific Ocean circulation and heat budget. Progress in Oceanography. 82:281-325.   10.1016/j.pocean.2009.08.002   AbstractWebsite

To address questions concerning the intensity and spatial structure of the three-dimensional circulation within the Pacific Ocean and the associated advective and diffusive property flux divergences, data from approximately 3000 high-quality hydrographic stations collected on 40 zonal and meridional cruises have been merged into a physically consistent model. The majority of the stations were occupied as part of the World Ocean Circulation Experiment (WOCE), which took place in the 1990s. These data are supplemented by a few pre-WOCE surveys of similar quality, and time-averaged direct-velocity and historical hydrographic measurements about the equator. An inverse box model formalism is employed to estimate the absolute along-isopycnal velocity field, the magnitude and spatial distribution of the associated diapycnal flow and the corresponding diapycnal advective and diffusive property flux divergences. The resulting large-scale WOCE Pacific circulation can be described as two shallow overturning cells at mid- to low latitudes, one in each hemisphere, and a single deep cell which brings abyssal waters from the Southern Ocean into the Pacific where they upwell across isopycnals and are returned south as deep waters. Upwelling is seen to occur throughout most of the basin with generally larger dianeutral transport and greater mixing occurring at depth. The derived pattern of ocean heat transport divergence is compared to published results based on air-sea flux estimates. The synthesis suggests a strongly east/west oriented pattern of air-sea heat flux with heat loss to the atmosphere throughout most of the western basins, and a gain of heat throughout the tropics extending poleward through the eastern basins. The calculated meridional heat transport agrees well with previous hydrographic estimates. Consistent with many of the climatologies at a variety of latitudes as well, our meridional heat transport estimates tend toward lower values in both hemispheres. (C) 2009 Elsevier Ltd. All rights reserved.

2008
Talley, LD.  2008.  Freshwater transport estimates and the global overturning circulation: Shallow, deep and throughflow components. Progress in Oceanography. 78:257-303.   10.1016/j.pocean.2008.05.001   AbstractWebsite

Meridional ocean freshwater transports and convergences are calculated from absolute geostrophic velocities and Ekman transports. The freshwater transports are analyzed in terms of mass-balanced contributions from the shallow, ventilated circulation of the subtropical gyres, intermediate and deep water overturns, and Indonesian Throughflow and Bering Strait components. The following are the major conclusions: 1. Excess freshwater in high latitudes must be transported to the evaporative lower latitudes, as is well known. The calculations here show that the northern hemisphere transports most of its high latitude freshwater equatorward through North Atlantic Deep Water (NADW) formation (as in [Rahmstorf, S., 1996. On the freshwater forcing and transport of the Atlantic thermohaline circulation. Climate Dynamics 12, 799-811]), in which saline subtropical surface waters absorb the freshened Arctic and subpolar North Atlantic surface waters (0.45 +/- 0.15 Sv for a 15 Sv overturn), plus a small contribution from the high latitude North Pacific through Bering Strait (0.06 +/- 0.02 Sv). In the North Pacific, formation of 2.4 Sv of North Pacific Intermediate Water (NPIW) transports 0.07 +/- 0.02 Sv of freshwater equatorward. In complete contrast, almost all of the 0.61 +/- 0.13 Sv of freshwater gained in the Southern Ocean is transported equatorward in the upper ocean, in roughly equal magnitudes of about 0.2 Sv each in the three subtropical gyres, with a smaller contribution of <0. 1 Sv from the Indonesian Throughflow loop through the Southern Ocean. The large Southern Ocean deep water formation (27 Sv) exports almost no freshwater (0.01 +/- 0.03 Sv) or actually imports freshwater if deep overturns in each ocean are considered separately (-0.06 +/- 0.04 Sv). This northern-southern hemisphere asymmetry is likely a consequence of the "Drake Passage" effect, which limits the southward transport of warm, saline surface waters into the Antarctic [Toggweiler, J.R., Samuels, B., 1995a. Effect of Drake Passage on the global thermohaline circulation. Deep-Sea Research 1 42(4), 477-500]. The salinity contrast between the deep Atlantic, Pacific and Indian source waters and the denser new Antarctic waters is limited by their small temperature contrast, resulting in small freshwater transports. No such constraint applies to NADW formation, which draws on warm, saline subtropical surface waters. 2. The Atlantic/Arctic and Indian Oceans are net evaporative basins, hence import freshwater via ocean circulation. For the Atlantic/Arctic north of 32 degrees S, freshwater import (0.28 +/- 0.04 Sv) comes from the Pacific through Bering Strait (0.06 0.02 Sv), from the Southern Ocean via the shallow gyre circulation (0.20 +/- 0.02 Sv), and from three nearly canceling conversions to the NADW layer (0.02 0.02 Sv): from saline Benguela Current surface water (-0.05 +/- 0.01 Sv), fresh AAIW (0.06 0.01 Sv) and fresh AABW/LCDW (0.01 0.01 Sv). Thus, the NADW freshwater balance is nearly closed within the Atlantic/Arctic Ocean and the freshwater transport associated with export of NADW to the Southern Ocean is only a small component of the Atlantic freshwater budget. For the Indian Ocean north of 32 degrees S, import of the required 0.37 +/- 0.10 Sv of freshwater comes from the Pacific through the Indonesian Throughflow (0.23 +/- 0.05 Sv) and the Southern Ocean via the shallow gyre circulation (0.18 +/- 0.02 Sv), with a small export southward due to freshening of bottom waters as they upwell into deep and intermediate waters (-0.04 +/- 0.03 Sv). The Pacific north of 28 degrees S is essentially neutral with respect to freshwater, -0.04 +/- 0.09 Sv. This is the nearly balancing sum of export to the Atlantic through Bering Strait (-0.07 +/- 0.02 Sv), export to the Indian through the Indonesian Throughflow (-0.17 +/- 0.05 Sv), a negligible export due to freshening of upwelled bottom waters (-0.03 +/- 0.03 Sv), and import of 0.23 +/- 0.04 Sv from the Southern Ocean via the shallow gyre circulation. 3. Bering Strait's small freshwater transport of <0.1 Sv helps maintains the Atlantic-Pacific salinity difference. However, proportionally large variations in the small Bering Strait transport would only marginally impact NADW salinity, whose freshening relative to saline surface water is mainly due to air-sea/runoff fluxes in the subpolar North Atlantic and Arctic. In contrast, in the Pacific, because the total overturning rate is much smaller than in the Atlantic, Bering Strait freshwater export has proportionally much greater impact on North Pacific salinity balances, including NPIW salinity. (C) 2008 Elsevier Ltd. All rights reserved.

Dong, S, Sprintall J, Gille ST, Talley L.  2008.  Southern Ocean mixed-layer depth from Argo float profiles. Journal of Geophysical Research-Oceans. 113   10.1029/2006jc004051   AbstractWebsite

Argo float profiles of temperature, salinity, and pressure are used to derive the mixed-layer depth (MLD) in the Southern Ocean. MLD is determined from individual profiles using both potential density and potential temperature criteria, and a monthly climatology is derived from individual MLDs using an objective mapping method. Quantitative data are available in the auxiliary material. The spatial structures of MLDs are similar in each month, with deep mixed layers within and just north of the Antarctic Circumpolar Current (ACC) in the Pacific and Indian oceans. The deepest mixed layers are found from June to October and are located just north of the ACC where Antarctic Intermediate Water (AAIW) and Subantarctic Mode Water ( SAMW) are formed. Examination of individual MLDs indicates that deep mixed layers ( MLD >= 400 m) from both the density and temperature criteria are concentrated in a narrow surface density band which is within the density range of SAMW. The surface salinity for these deep mixed layers associated with the SAMW formation are slightly fresher compared to historical estimates. Differences in air-sea heat exchanges, wind stress, and wind stress curl in the Pacific and Indian oceans suggest that the mode water formation in each ocean basin may be preconditioned by different processes. Wind mixing and Ekman transport of cold water from the south may assist the SAMW formation in the Indian Ocean. In the eastern Pacific, the formation of mode water is potentially preconditioned by the relative strong cooling and weak stratification from upwelling.

Brambilla, E, Talley LD.  2008.  Subpolar Mode Water in the northeastern Atlantic: 1. Averaged properties and mean circulation. Journal of Geophysical Research-Oceans. 113   10.1029/2006jc004062   AbstractWebsite

Subpolar Mode Waters (SPMW) in the eastern North Atlantic subpolar gyre are investigated with hydrographic and Lagrangian data (surface drifters and isopycnal floats). Historical hydrographic data show that SPMWs are surface water masses with nearly uniform properties, confined between the ocean surface and the permanent pycnocline. SPMWs represented by densities 27.3(sigma theta), 27.4(sigma theta), and 27.5(sigma theta) are present in the eastern subpolar gyre and are influenced by the topography and the regional circulation. Construction of an absolute surface stream function from surface drifters shows that SPMWs are found along the mean path of each of the several branches of the North Atlantic Current (NAC) and their density increases gradually downstream. The Rockall Trough branch of the NAC carries 27.3(sigma theta), 27.4(sigma theta), and 27.5(sigma theta) SPMW toward the Iceland-Faroe Front. In the Iceland Basin, the Subarctic Front along the western flank of the Rockall Plateau carries a similar sequence of SPMW. The western side of the Central Iceland Basin branch of the NAC, on the other hand, veers westward and joins the East Reykjanes Ridge Current, feeding the 27.5(sigma theta) SPMW on the Reykjanes Ridge. The separation among the various NAC branches most likely explains the different properties that characterize the 27.5(sigma theta) SPMW found on the Reykjanes Ridge and on the Iceland-Faroe Ridge. Since the branches of the NAC have a dominant northeastward direction, the newly observed distribution of SPMW combined with the new stream function calculation modify the original hypothesis of McCartney and Talley (1982) of a smooth cyclonic pathway for SPMW advection and density increase around the subpolar gyre.

Brambilla, E, Talley LD, Robbins PE.  2008.  Subpolar Mode Water in the northeastern Atlantic: 2. Origin and transformation. Journal of Geophysical Research-Oceans. 113   10.1029/2006jc004063   AbstractWebsite

The processes that lead to the transformation and origin of the eastern North Atlantic Subpolar Mode Waters (SPMW) are investigated from observational data using an extended Walin framework. Air-sea flux data from the National Oceanography Center, Southampton (NOCS), and hydrographic data from the A24 cruise collected during the World Ocean Circulation Experiment (WOCE) are used to estimate the contribution of diapycnal and isopycnal fluxes to the density classes that include SPMW. Surface diapycnal volume flux is the dominant source of waters in the SPMW density. In the North Atlantic subpolar gyre the diapycnal volume flux occurs along the main branches of the North Atlantic Current (NAC) and it has an average transport of 14 +/- 6.5 Sv, with a maximum of 21.5 Sv across the 27.35(sigma theta) isopycnal. The regional distribution of the diapycnal flux on isopycnal surfaces is computed to identify the areas with the largest diapycnal flux. These regions coincide with the location of SPMW based on potential vorticity. The surface diapycnal flux is associated with obduction and subduction through the permanent pycnocline. Therefore, the water involved in the transformation of SPMWs is continuously exchanged with the ocean interior. In addition, we suggest that subduction is not associated with smooth advection from the mixed layer to the ocean interior, but is water mass loss entrainment into the deep overflows of the subpolar gyre. The isopycnal component of the SPMW throughput is estimated from the geostrophic transport across the A24 section from Greenland to Scotland and is 10% to 40% of the diapycnal flux.

2007
Tishchenko, PY, Talley LD, Lobanov VB, Nedashkovskii AP, Pavlova GY, Sagalaev SG.  2007.  The influence of geochemical processes in the near-bottom layer on the hydrochemical characteristics of the waters of the Sea of Japan. Oceanology. 47:350-359.   10.1134/s0001437007030071   AbstractWebsite

According to the results of the international expedition aboard the R/Vs Roger Revelle and Professor Khromov in the summer 1999, areas with low oxygen contents (below 210 mu M/kg) and those with increased contents of dissolved inorganic carbon and phosphates were found that roughly coincided with one another. These areas are located near the bottom on the southwestern slope of the Tsushima Basin in the region of the Korea Strait and on the continental slope in the region of the Tatar Strait in the northern part of the sea at about 46 degrees N. The set of hydrochemical data points to a high geochemical activity in the near-bottom layer of the areas noted. This activity is confirmed by direct observations of the composition of the interstitial water in the sediments collected in the northern part of the sea during the expedition of R/V Akademik M.A. Lavrent'ev in 2003. It was supposed that the main cause of the increased geochemical activity is the runoff of suspended and dissolved matter from the Korea and Tatar straits. In the areas mentioned, the near-bottom waters are characterized by low values of the nitrogen-phosphorus ratio (below 10), which is geochemical proof of the denitrification process occurring under the conditions of high oxygen concentrations characteristic of the Sea of Japan. Based on the value of the annual production in the Sea of Japan, a rate of denitrification equal to 3.4 x 10(12) gN/year was calculated. Hence, it is confirmed that the geochemical processes in the near-bottom layer have a direct influence on the spatiotemporal characteristics of the hydrochemical properties of the waters of the Sea of Japan.

Oka, E, Talley LD, Suga T.  2007.  Temporal variability of winter mixed layer in the mid- to high-latitude North Pacific. Journal of Oceanography. 63:293-307.   10.1007/s10872-007-0029-2   AbstractWebsite

Temperature and salinity data from 2001 through 2005 from Argo profiling floats have been analyzed to examine the time evolution of the mixed layer depth (MLD) and density in the late fall to early spring in mid to high latitudes of the North Pacific. To examine MLD variations on various time scales from several days to seasonal, relatively small criteria (0.03 kg m(-3) in density and 0.2 degrees C in temperature) are used to determine MLD. Our analysis emphasizes that maximum MLD in some regions occurs much earlier than expected. We also observe systematic differences in timing between maximum mixed layer depth and density. Specifically, in the formation regions of the Subtropical and Central Mode Waters and in the Bering Sea, where the winter mixed layer is deep, MLD reaches its maximum in late winter (February and March), as expected. In the eastern subarctic North Pacific, however, the shallow, strong, permanent halocline prevents the mixed layer from deepening after early January, resulting in a range of timings of maximum MLD between January and April. In the southern subtropics; from 20 degrees to 30 degrees N, where the winter mixed layer is relatively shallow, MLD reaches a maximum even earlier in December-January. In each region, MLD fluctuates on short time scales as it increases from late fall through early winter. Corresponding to this short-term variation, maximum MLD almost always occurs 0 to 100 days earlier than maximum mixed layer density in all regions.

Talley, LD.  2007.  Hydrographic Atlas of the World Ocean Circulation Experiment (WOCE). Volume 2: Pacific Ocean. ( Sparrow M, Chapman P, Gould J, Eds.)., Southampton, UK: International WOCE Project Office Abstract

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Bindoff, NL, Willebrand J, Artale V, Cazenave A, Gregory J, Gulev S, Hanawa K, Le Quere C, Levitus S, Nojiri Y, Shum CK, Talley LD, Unnikrishnan A.  2007.  Observations: Oceanic Climate Change and Sea Level. Climate change 2007 : the physical science basis : contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. ( Solomon S, Qin D, Manning M, Chen Z, Marquis M, Avery KB, Tignor M, Miller H, Eds.).:387-432., Cambridge ; New York: Cambridge University Press Abstract
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2006
Park, GH, Lee K, Tishchenko P, Min DH, Warner MJ, Talley LD, Kang DJ, Kim KR.  2006.  Large accumulation of anthropogenic CO(2) in the East (Japan) Sea and its significant impact on carbonate chemistry. Global Biogeochemical Cycles. 20   10.1029/2005gb002676   AbstractWebsite

[ 1] This paper reports on a basin-wide inventory of anthropogenic CO(2) in the East ( Japan) Sea determined from high-quality alkalinity, chlorofluorocarbon, and nutrient data collected during a summertime survey in 1999 and total dissolved inorganic carbon data calculated from pH and alkalinity measurements. The data set comprises measurements from 203 hydrographic stations and covers most of the East Sea with the exception of the northwestern boundary region. Anthropogenic CO(2) concentrations are estimated by separating this value from total dissolved inorganic carbon using a tracer-based ( chlorofluorocarbon) separation technique. Wintertime surface CFC-12 data collected in regions of deep water formation off Vladivostok, Russia, improve the accuracy of estimates of anthropogenic CO(2) concentrations by providing improved air-sea CO(2) disequilibrium values for intermediate and deep waters. Our calculation yields a total anthropogenic CO(2) inventory in the East Sea of 0.40 +/- 0.06 petagrams of carbon as of 1999. Anthropogenic CO(2) has already reached the bottom of the East Sea, largely owing to the effective transport of anthropogenic CO(2) from the surface to the ocean interior via deep water formation in the waters off Vladivostok. The highest specific column inventory ( vertically integrated inventory per square meter) of anthropogenic CO(2) of 80 mol C m(-2) is found in the Japan Basin ( 40 degrees N - 44 degrees N). Comparison of this inventory with those for other major basins of the same latitude band reveal that the East Sea values are much higher than the inventory for the Pacific Ocean (20 - 30 mol C m(-2)) and are similar to the inventory for the North Atlantic (66 - 72 mol C m(-2)). The substantial accumulation of anthropogenic CO(2) in the East Sea during the industrial era has caused the aragonite and calcite saturation horizons to move upward by 80 - 220 m and 500 - 700 m, respectively. These upward movements are approximately 5 times greater than those found in the North Pacific. Both the large accumulation of anthropogenic CO(2) and its significant impact on carbonate chemistry in the East Sea suggest that this sea is an important site for monitoring the future impact of the oceanic invasion of anthropogenic CO(2).

Brambilla, E, Talley LD.  2006.  Surface drifter exchange between the North Atlantic subtropical and subpolar gyres. Journal of Geophysical Research-Oceans. 111   10.1029/2005jc003146   AbstractWebsite

[ 1] Surface drifters deployed in the subtropical and subpolar North Atlantic from 1990 to 2002 show almost no connection between the subtropical and subpolar gyres; only one drifter crosses the intergyre boundary even though other data types ( e. g., dynamic topography and tracers) suggest a major connection. Two of several possible causes for the lack of intergyre connectivity in this two-dimensional data set are examined: ( 1) undersampling and short drifter lifetime leading to underestimation of the northward flow, and ( 2) the southward mean Ekman velocity. Advection of a large number of long-lived synthetic drifters through the observed mean velocity results in a 5% increase in cross-gyre flux compared with that for synthetic drifters with realistic lifetimes. By further advecting synthetic drifters through the observed mean velocity field with and without the Ekman component, estimated from the wind field associated with the actual drifters, it is shown that removal of the Ekman component further increases the intergyre flux by up to 6%. With a turbulent component added to the mean velocity field to simulate the eddy field, there is a further increase in connection by 5%. Thus the Ekman and eddy contributions to the drifter trajectories nearly cancel each other. Consideration of three-dimensional processes ( subduction and obduction) is reserved for complete modeling studies.

Fiedler, PC, Talley LD.  2006.  Hydrography of the eastern tropical Pacific: A review. Progress in Oceanography. 69:143-180.   10.1016/j.pocean.2006.03.008   AbstractWebsite

Eastern tropical Pacific Ocean waters lie at the eastern end of a basin-wide equatorial current system, between two large subtropical gyres and at the terminus of two eastern boundary currents. Descriptions and interpretations of surface, pycnocline, intermediate and deep waters in the region are reviewed. Spatial and temporal patterns are discussed using (1) maps of surface temperature, salinity, and nutrients (phosphate, silicate, nitrate and nitrite), and thermocline and mixed layer parameters, and (2) meridional and zonal sections of temperature, salinity, potential density, oxygen, and nutrients. These patterns were derived from World Ocean Database observations by an ocean interpolation algorithm: loess-weighted observations were projected onto quadratic functions of spatial coordinates while simultaneously fitting annual and semiannual harmonics and the Southern Oscillation Index to account for interannual variability. Contrasts between the equatorial cold tongue and the eastern Pacific warm pool are evident in all the hydrographic parameters. Annual cycles and ENSO (El Nino-Southern Oscillation) variability are of similar amplitude in the eastern tropical Pacific, however, there are important regional differences in relative variability at these time scales. Unique characteristics of the eastern tropical Pacific are discussed: the strong and shallow pycnocline, the pronounced oxygen minimum layer, and the Costa Rica Dome. This paper is part of a comprehensive review of the oceanography of the eastern tropical Pacific. (c) 2006 Elsevier Ltd. All rights reserved.

Talley, LD, Min DH, Lobanov VB, Luchin VA, Ponomarev VI, Salyuk AN, Shcherbina AY, Tishchenko PY, Zhabin I.  2006.  Japan/East Sea water masses and their relation to the sea's circulation. Oceanography. 19:32-49.   10.5670/oceanog.2006.42   Abstract

The Japan/East Sea is a major anomaly in the ventilation and overturn picture of the Pacific Ocean. The North Pacific is well known to be nearly unventilated at intermediate and abyssal depths, reflected in low oxygen concentration at 1000 m (Figure 1). (High oxygen indicates newer water in more recent contact with the atmosphere. Oxygen declines as water "ages" after it leaves the sea surface mainly because of bacterial respiration.) Even the small production of North Pacific Intermediate Water in the Okhotsk Sea (Talley, 1991; Shcherbina et al., 2003) and the tiny amount of new bottom water encountered in the deep Bering Sea (Warner and Roden, 1995) have no obvious impact on the overall oxygen distribution at 1000 m and below, down to 3500 m, which is the approximate maximum depth of the Bering, Okhotsk, and Japan/East Seas.

2005
Talley, LD, Sprintall J.  2005.  Deep expression of the Indonesian Throughflow: Indonesian Intermediate Water in the South Equatorial Current. Journal of Geophysical Research-Oceans. 110   10.1029/2004jc002826   AbstractWebsite

[1] The narrow westward flow of the South Equatorial Current ( SEC), centered at 12 degrees S and carrying freshened water from the Indonesian seas, is traced across the Indian Ocean using data from the World Ocean Circulation Experiment. The jet is remarkably zonal and quasi-barotropic, following the potential vorticity contours characteristic of the tropics, separating higher-oxygen and lower-nutrient waters of the subtropics from the oxygen-depleted waters of the tropics. The fresh surface waters are the usual Indonesian Throughflow Water reported previously. Less well studied is the intermediate-depth SEC carrying fresher water from the Banda Sea and Pacific, known as Indonesian Intermediate Water (IIW) or Banda Sea Intermediate Water. The high-silica signature of IIW is documented here, permitting us to ( 1) trace the spread of IIW from sill density at Leti Strait to higher density as it is diluted toward the west and ( 2) define an IIW core for transport estimates, of 3 to 7 Sv westward, using geostrophic and LADCP velocities. The high IIW silica is traced to the Banda Sea, arising from known diapycnal mixing of Pacific waters entering through Lifamatola Strait and local sources. New heat, freshwater, oxygen, and silica budgets within the Indonesian seas suggest at least 3 Sv of inflow through the relatively deep Lifamatola Strait, supplementing the observed 9 Sv through the shallower Makassar Strait. Both shallow and deep inflows and outflows, along with vigorous mixing and internal sources within the Indonesian seas, are required to capture the transformation of Pacific to Indonesian Throughflow waters.

Treguier, AM, Theetten S, Chassignet EP, Penduff T, Smith R, Talley L, Beismann JO, Boning C.  2005.  The North Atlantic subpolar gyre in four high-resolution models. Journal of Physical Oceanography. 35:757-774.   10.1175/jpo2720.1   AbstractWebsite

The authors present the first quantitative comparison between new velocity datasets and high-resolution models in the North Atlantic subpolar gyre [1/10 degrees Parallel Ocean Program model (POPNA10), Miami Isopycnic Coordinate Ocean Model (MICOM), 1/6 degrees Atlantic model (ATL6), and Family of Linked Atlantic Ocean Model Experiments (FLAME)]. At the surface, the model velocities agree generally well with World Ocean Circulation Experiment (WOCE) drifter data. Two noticeable exceptions are the weakness of the East Greenland coastal current in models and the presence in the surface layers of a strong southwestward East Reykjanes Ridge Current. At depths, the most prominent feature of the circulation is the boundary current following the continental slope. In this narrow flow, it is found that gridded float datasets cannot be used for a quantitative comparison with models. The models have very different patterns of deep convection, and it is suggested that this could be related to the differences in their barotropic transport at Cape Farewell. Models show a large drift in watermass properties with a salinization of the Labrador Sea Water. The authors believe that the main cause is related to horizontal transports of salt because models with different forcing and vertical mixing share the same salinization problem. A remarkable feature of the model solutions is the large westward transport over Reykjanes Ridge [10 Sv (Sv = 10(6) m(3) s(-1)) or more].