Publications with links

Export 149 results:
Sort by: [ Author  (Desc)] Title Type Year
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 
T
Talley, LD, Joyce TM.  1992.  The Double Silica Maximum in the North Pacific. Journal of Geophysical Research-Oceans. 97:5465-5480.   10.1029/92jc00037   AbstractWebsite

The North Pacific has two vertical silica maxima. The well-known intermediate maximum occurs between 2000 and 2500 m with a potential density relative to 2000 dbar of 36.90 in the northeastern Pacific. The deep maximum, which has not been observed extensively before, is found at or near the ocean bottom in the northern North Pacific in a narrow latitude range. Maps of silica on isopycnals which intersect the intermediate and bottom maxima show that the lowest silica is found in the western tropical North Pacific, suggesting a route for the spread of South Pacific water into the deep North Pacific. Low-silica water is found along the western boundary of the North Pacific, with a separate broad tongue south of Hawaii. The highest silica on both isopycnals is in the northeast Pacific. A bottom maximum in the Cascadia Basin in the northeastern Pacific can be differentiated from both open-ocean maxima. Four sources for the vertical maxima are considered: in situ dissolution of sinking panicles, bottom sediment dissolution, hydrothermal venting, and upslope advection in the northeastern Pacific. Because not enough is known about any of these sources, only rough estimates of their contributions can be made. The bottom maximum is most likely to result from bottom sediment dissolution but requires a flux larger than some current direct estimates. The Cascadia Basin bottom maximum may result from both bottom sediment dissolution and hydrothermal venting. The intermediate maximum is likely to result primarily from dissolution of sinking particles. There is no quantitative estimate of the effect of possible upslope advection or enhancement of bottom fluxes due to the Columbia River outflow.

Talley, LD.  1999.  Some aspects of ocean heat transport by the shallow, intermediate and deep overturning circulations. Mechanisms of global climate change at millennial time scales. ( Clark PU, Webb RS, Keigwin LD, Eds.).:1-22., Washington, DC: American Geophysical Union Abstract
n/a
Talley, LD.  1984.  Meridional Heat-Transport in the Pacific-Ocean. Journal of Physical Oceanography. 14:231-241.   10.1175/1520-0485(1984)014<0231:mhtitp>2.0.co;2   AbstractWebsite

The heat transported meridionally in the Pacific Ocean is calculated from the surface heat budgets of Clark and Weare and others; both budgets were based on Bunker's method with different radiation formulas. The meridional heat transport is also calculated from the surface heat budget of Esbensen and Kushnir, who used Budyko's method. The heat transport is southward at most latitudes if the numbers of Clark and of Weare are used. It is northward in the North Pacific and southward in the South Pacific if Eshensen and Kushnir's numbers are used. Systematic errors in both calculations appear to be so large that confident determination of even the sign of the heat transport in the North Pacific is not possible. The amount of heat transported poleward by all oceans is obtained from the Pacific Ocean calculation and transports in the Atlantic and Indian Oceans based on Bunker's surface heat fluxes.

Talley, LD, Reid JL, Robbins PE.  2003.  Data-based meridional overturning streamfunctions for the global ocean. Journal of Climate. 16:3213-3226.   10.1175/1520-0442(2003)016<3213:dmosft>2.0.co;2   AbstractWebsite

The meridional overturning circulation for the Atlantic, Pacific, and Indian Oceans is computed from absolute geostrophic velocity estimates based on hydrographic data and from climatological Ekman transports. The Atlantic overturn includes the expected North Atlantic Deep Water formation ( including Labrador Sea Water and Nordic Sea Overflow Water), with an amplitude of about 18 Sv through most of the Atlantic and an error of the order of 3 - 5 Sv (1 Sv = 10(6) m(3) s(-1)). The Lower Circumpolar Deep Water ( Antarctic Bottom Water) flows north with about 8 Sv of upwelling and a southward return in the South Atlantic, and 6 Sv extending to and upwelling in the North Atlantic. The northward flow of 8 Sv in the upper layer in the Atlantic ( sea surface through the Antarctic Intermediate Water) is transformed to lower density in the Tropics before losing buoyancy in the Gulf Stream and North Atlantic Current. The Pacific overturning streamfunction includes 10 Sv of Lower Circumpolar Deep Water flowing north into the South Pacific to upwell and return southward as Pacific Deep Water, and a North Pacific Intermediate Water cell of 2 Sv. The northern North Pacific has no active deep water formation at the sea surface, but in this analysis there is downwelling from the Antarctic Intermediate Water into the Pacific Deep Water, with upwelling in the Tropics. For global Southern Hemisphere overturn across 30degreesS, the overturning is separated into a deep and a shallow overturning cell. In the deep cell, 22 - 27 Sv of deep water flows southward and returns northward as bottom water. In the shallow cell, 9 Sv flows southward at low density and returns northward just above the intermediate water density. In all three oceans, the Tropics appear to dominate upwelling across isopycnals, including the migration of the deepest waters upward to the thermocline in the Indian and Pacific. Estimated diffusivities associated with this tropical upwelling are the same order of magnitude in all three oceans. It is shown that vertically varying diffusivity associated with topography can produce deep downwelling in the absence of external buoyancy loss. The rate of such downwelling for the northern North Pacific is estimated as 2 Sv at most, which is smaller than the questionable downwelling derived from the velocity analysis.

Talley, LD.  2013.  Hydrographic Atlas of the World Ocean Circulation Experiment (WOCE). Volume 4: Indian Ocean. ( and M. Sparrow CPJ, Ed.)., Southampton, U.K.: International WOCE Project Office
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

n/a

Talley, LD, Rosso I, Kamenkovich I, Mazloff MR, Wang J, Boss E, Gray AR, Johnson KS, Key RM, Riser SC, Williams NL, Sarmiento JL.  2019.  Southern Ocean biogeochemical float deployment strategy, with example from the Greenwich meridian line (GO-SHIP A12). Journal of Geophysical Research-Oceans. 124:403-431.   10.1029/2018jc014059   AbstractWebsite

Biogeochemical Argo floats, profiling to 2,000-m depth, are being deployed throughout the Southern Ocean by the Southern Ocean Carbon and Climate Observations and Modeling program (SOCCOM). The goal is 200 floats by 2020, to provide the first full set of annual cycles of carbon, oxygen, nitrate, and optical properties across multiple oceanographic regimes. Building from no prior coverage to a sparse array, deployments are based on prior knowledge of water mass properties, mean frontal locations, mean circulation and eddy variability, winds, air-sea heat/freshwater/carbon exchange, prior Argo trajectories, and float simulations in the Southern Ocean State Estimate and Hybrid Coordinate Ocean Model (HYCOM). Twelve floats deployed from the 2014-2015 Polarstern cruise from South Africa to Antarctica are used as a test case to evaluate the deployment strategy adopted for SOCCOM's 20 deployment cruises and 126 floats to date. After several years, these floats continue to represent the deployment zones targeted in advance: (1) Weddell Gyre sea ice zone, observing the Antarctic Slope Front, and a decadally-rare polynya over Maud Rise; (2) Antarctic Circumpolar Current (ACC) including the topographically steered Southern Zone chimney where upwelling carbon/nutrient-rich deep waters produce surprisingly large carbon dioxide outgassing; (3) Subantarctic and Subtropical zones between the ACC and Africa; and (4) Cape Basin. Argo floats and eddy-resolving HYCOM simulations were the best predictors of individual SOCCOM float pathways, with uncertainty after 2years of order 1,000km in the sea ice zone and more than double that in and north of the ACC.

Talley, LD.  1983.  Radiating Barotropic Instability. Journal of Physical Oceanography. 13:972-987.   10.1175/1520-0485(1983)013<0972:rbi>2.0.co;2   AbstractWebsite

The linear stability of zonal, parallel shear flow on a beta-plane is discussed. While the localized shear region supports unstable waves, the far-field can support Rossby waves because of the ambient potential-vorticity gradient. An infinite zonal flow with a continuous cross-stream velocity gradient is approximated with segments of uniform flow, joined together by segments of uniform potential vorticity. This simplification allows an exact dispersion relation to be found. There are two classes of linearly unstable solutions. One type is trapped to the source of energy and has large growth rates. The second type is weaker instabilities which excite Rossby waves in the far-field: the influence of these weaker instabilities extends far beyond that of the most unstable waves.

Talley, LD.  1996.  Physical oceanography. Encylopedia of Earth Sciences. :745-749., New York: MacMillan Publishing Abstract
n/a
Talley, LD, Johnson GC.  1994.  Deep, Zonal Subequatorial Currents. Science. 263:1125-1128.   10.1126/science.263.5150.1125   AbstractWebsite

Large-scale, westward-extending tongues of warm (Pacific) and cold (Atlantic) water are found between 2000 and 3000 meters both north and south of the equator in the Pacific and Atlantic oceans. They are centered at 5-degrees to 8-degrees north and 10-degrees to 15-degrees south (Pacific) and 5-degrees to 8-degrees north and 15-degrees to 20-degrees south (Atlantic). They are separated in both oceans by a contrasting eastward-extending tongue, centered at about 1-degrees to 2-degrees south, in agreement with previous helium isotope observations (Pacific). Thus, the indicated deep tropical westward flows north and south of the equator and eastward flow near the equator may result from more general forcing than the hydrothermal forcing previously hypothesized.

Talley, LD, Stammer D, Fukumori I.  2001.  The WOCE Synthesis. Ocean circulation and climate : observing and modelling the global ocean. ( Siedler G, Church J, Gould WJ, Eds.).:525-546., San Diego, Calif. London: Academic Abstract
n/a
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.

Talley, LD, White WB.  1987.  Estimates of Time and Space Scales at 300-Meters in the Midlatitude North Pacific from the Transpac-Xbt Program. Journal of Physical Oceanography. 17:2168-2188.   10.1175/1520-0485(1987)017<2168:eotass>2.0.co;2   AbstractWebsite

Estimates of length and time scales of temperature variability at 300 meters in the midlatitude North Pacific are made. Data are XBT traces collected from 1976 to 1984 in the TRANSPAC Volunteer Observing Ship program. Temperatures at 300 meters are grouped in two-mouth bins and gridded using the Surface II mapping program.Temperature variance about the time mean is largest in the Kuroshio Extension and nearly constant in the eastern North Pacific. A cooling trend occurred in the eastern North Pacific over the eight years of the dataset. In the western Pacific, the annual cycle is most intense 1°–2° north of the Kuroshio Extension, with an indication of meridional propagation away from the region of most intense variability. Propagation of annual waves in the eastern Pacific was predominantly northwestward.Wavenumber and frequency spectra are computed from normalized temperatures with the mean and bimonthly average removed in order to eliminate the dominant annual cycle. Based on the overall temperature variance, the North Pacific was divided into western and eastern regions. Zonal wavenumber and frequency spectra and two-dimensional ω/k spectra were computed for a number of latitudes in the eastern and western regions. Two-dimensional k/l spectra were also computed for the western and eastern regions. The spectra indicate westward propagation throughout the midlatitude North Pacific with additional eastward propagation in the Kuroshio Extension region, shorter length and time scales in the Kuroshio Extension compared with other regions, and slight dominance of southwestward propagation in bath the eastern and western North Pacific.Tests to determine the effective spatial resolution of the dataset indicate that local average-station spacing is a good measure of local Nyquist wavelength. However, because of the nearly random sampling in a spatially limited region, an unresolved wave is aliased more or less in a band stretching towards low wavenumber rather than folded in coherent, predictable locations in the spectrum. With the choice of a two-month time bin, spectra are about equally aliased in space and time, with Nyquist wavelength and period close to the beginning of energy rolloff reported in other surveys, which have better spatial resolution but less degrees of freedom.

Talley, LD, Baringer MO.  1997.  Preliminary results from WOCE hydrographic sections at 80 degrees E and 32 degrees S in the central Indian Ocean. Geophysical Research Letters. 24:2789-2792.   10.1029/97gl02657   AbstractWebsite

The hydrographic properties and circulation along sections at 80 degrees E and 32 degrees S in March, 1995, in the Indian Ocean are described very briefly. A halocline was well-developed in the tropics. A westward coastal jet of fresh Bay of Bengal water was present at the sea surface at Sri Lanka with eastward flow of saline Arabian Sea water below. The Equatorial Undercurrent was well developed as were the deep equatorial jets. The Indonesian throughflow jet presented a large dynamic signature at 10 to 14 degrees S coinciding with a strong front in all properties to great depth. Its mid-depth salinity minimum is separated from that of the Antarctic Intermediate Water. The Subantarctic Mode Water of the southeastern Indian Ocean imparts its high oxygen ventilation signature to the whole of the transects, including the tropical portion. The deepest water in the Central Indian Basin is pooled in the center of the basin, and its principal source appears to be the sill at 11 degrees S through the Ninetyeast Ridge. Northward deep water transports across the 32 degrees S section were similar to those observed in 1987 but the deep water was lower in oxygen and fresher than in 1987. Upper ocean waters at 32 degrees S were more saline and warmer in 1995.

Talley, LD, Nagata Y, Fujimura M, Iwao T, Kono T, Inagake D, Hirai M, Okuda K.  1995.  North Pacific Intermediate Water in the Kuroshio Oyashio Mixed Water Region. Journal of Physical Oceanography. 25:475-501.   10.1175/1520-0485(1995)025<0475:npiwit>2.0.co;2   AbstractWebsite

The North Pacific Intermediate Water (NPIW) orginates as a vertical salinity minimum in the mixed water region (MWR) between the Kuroshio and Oyashio, just east of Japan. Salinity minima in this region are examined and related to the water mass structures, dynamical features, and winter mixed layer density of waters of Oyashio origin. Stations in the MWR are divided into five regimes, of which three represent source waters (from the Kuroshio, Oyashio, and Tsugaru Current) and two are mixed waters formed from these three inputs. Examination of NPIW at stations just east of the MWR indicates that the mixed waters in the MWR are the origin of the newest NPIW. Multiple salinity minima with much finestructure are seen throughout the MWR in spring 1989, with the most fragmented occurring around the large warm core ring centered at 37 degrees N, 144 degrees E, suggesting that this is a dominant site for salinity minimum formation. The density of the NPIW in the MWR is slightly higher than the apparent late winter surface density of the subpolar water. It is hypothesized that the vertical mixing that creates interfacial layers above the salinity minima also increases the density of the minima to the observed NPIW density. Transport of new intermediate water (26.65-27.4 sigma(theta)) eastward out of the MWR is about 6 Sv (Sv = 10(6)m(3)s(-1)), of which roughly 45% is of Oyashio origin and the other 55% of Kuroshio origin. Therefore, the transport of subpolar water into the subtropical gyre in the western North Pacific is estimated to be about 3 Sv.

Talley, LD.  1985.  Ventilation of the Sub-Tropical North Pacific - the Shallow Salinity Minimum. Journal of Physical Oceanography. 15:633-649.   10.1175/1520-0485(1985)015<0633:votsnp>2.0.co;2   AbstractWebsite

The shallow salinity minimum of the subtropical North Pacific is shown to be a feature of the ventilated, wind-driven circulation. Subduction of low salinity surface water in the northeastern subtropical gyre beneath higher salinity water to the south causes the salinity minimum. Variation of salinity along surface isopycnals causes variations in density and salinity at the minimum.A model of ventilated flow is used to demonstrate how the shallow salinity minimum can arise. The model is modified to account for nonzonal, realistic winds; it is also extended to examine the three-dimensional structure of the western shadow zone. The boundary between the subtropical and subpolar gyres is given by the zero of the zonal integral of Ekman pumping. The western shadow zone fills the subtropical gyre at the base of the ventilated layers and decreases in extent with decreasing density. For parameters appropriate to the North Pacific, the eastern shadow zone is of very limited extent.Observations of salinity and potential vorticity within and below the ventilated layer bear out model predictions of the extent of the western shadow zone.

S
Suga, T, Talley LD.  1995.  Antarctic Intermediate Water Circulation in the Tropical and Subtropical South-Atlantic. Journal of Geophysical Research-Oceans. 100:13441-13453.   10.1029/95jc00858   AbstractWebsite

Recent hydrographic data from the South Atlantic Ventilation Experiment cruises and others are combined with historical data and used to map the isopycnal properties corresponding to the Antarctic Intermediate Water (AAIW) in the Atlantic Ocean. The low salinity of the AAIW extends eastward across the South Atlantic just south of the equator (3-4 degrees S). Evidence of a weak eastward flow just north of the equator (1-2 degrees N) is also shown. Lateral and vertical homogenization of properties in the AAIW is found at the equator between 2 degrees S and 2 degrees N; there is no clear zonal gradient in salinity just along the equator. These observations suggest enhanced mixing within the equatorial baroclinic deformation radius. The South Atlantic tropical gyre is shown to consist of the following three cells: one cyclonic cell centered at about 7 degrees S, another centered at about 19 degrees S in the west and 23 degrees S in the east, and one anticyclonic cell centered at about 13 degrees S. These cells are associated with a westward extension at 10 degrees S of high salinity and low oxygen which originates in the eastern tropical South Atlantic and a front in these properties at about 15 degrees S in the west and about 20 degrees S in the east.

Speer, KG, Siedler G, Talley L.  1995.  The Namib Col Current. Deep-Sea Research Part I-Oceanographic Research Papers. 42:1933-1950.   10.1016/0967-0637(95)00088-7   AbstractWebsite

Recent measurements indicate the transatlantic extent of the Namib Col Current at depths of 1300-3000 m near Lat. 22 degrees S in the South Atlantic Ocean. This current forms a continuous circulation structure from the Namib Col on the Walvis Ridge to the western trough, though its characteristic change as deepwater with varying properties enters and leaves the current owing to a meridional flow component. Transport estimates from hydrographic sections on the Walvis Ridge and at 15 degrees W near the crest of the Mid-Atlantic Ridge indicate a strength of about 3 x 10(6) m(3) s(-1) The current is part of a larger-scale eastward Row at Lon. 25 degrees W; transport estimates across the salinity maximum core there show a similar strength. Associated with this high-salinity high-oxygen current is a basin-wide front in these properties of varying intensity (weaker in the east) marking the transition to deep water whose North Atlantic characteristics have been partly erased by mixing with Circumpolar Deep Water in the southwest South Atlantic. The water which finally crosses the Walvis Ridge is supplied both by the eastward flow of this (diluted) North Atlantic Deep Water and by a general southeastward interior flow from the northern Angola Basin. Evidence suggests that this deep water continues south in the eastern Cape Basin, leaving the South Atlantic near the African continent.

Snyder, S, Franks PJS, Talley LD, Xu Y, Kohin S.  2017.  Crossing the line: Tunas actively exploit submesoscale fronts to enhance foraging success. Limnology and Oceanography Letters. 2:187-194.   10.1002/lol2.10049   Abstract

Fronts—i.e., the boundaries between water masses—are ubiquitous in the world oceans and have been shown to significantly influence pelagic ecosystems with enhanced local productivity and increased abundances of forage fish and top predators. Here we use data from archival tags to document how four juvenile albacore tunas foraged at and exploited a thermal front. Of the 3098 observed trips, the albacore mainly swam across the front between the warm side above the thermocline and the cold side below the thermocline with an average of 78 ± 20.4 cross-frontal trips per fish per day. The warm frontal surface waters provided a thermal resource, allowing the tuna to maintain higher body temperatures and thus forage more efficiently in the food-rich waters of the cold side of the front. Foraging success of the tunas decreased as the cross-front thermal gradient weakened. This first look into small-scale use of fronts by a top predator demonstrates that ephemeral, submesoscale oceanic features can play a significant role in pelagic ecology.

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.

Sloyan, BM, Wanninkhof R, Kramp M, Johnson GC, Talley LD, Tanhua T, McDonagh E, Cusack C, O'Rourke E, McGovern E, Katsumata K, Diggs S, Hummon J, Ishii M, Azetsu-Scott K, Boss E, Ansorge I, Perez FF, Mercier H, Williams MJM, Anderson L, Lee JH, Murata A, Kouketsu S, Jeansson E, Hoppema M, Campos E.  2019.  The Global Ocean Ship-Based Hydrographic Investigations Program (GO-SHIP): A platform for integrated multidisciplinary ocean science. Frontiers in Marine Science. 6   10.3389/fmars.2019.00445   AbstractWebsite

The Global Ocean Ship-Based Hydrographic Investigations Program (GO-SHIP) provides a globally coordinated network and oversight of 55 sustained decadal repeat hydrographic reference lines. GO-SHIP is part of the global ocean/climate observing systems (GOOS/GCOS) for study of physical oceanography, the ocean carbon, oxygen and nutrient cycles, and marine biogeochemistry. GO-SHIP enables assessment of the ocean sequestration of heat and carbon, changing ocean circulation and ventilation patterns, and their effects on ocean health and Earth's climate. Rapid quality control and open data release along with incorporation of the GO-SHIP effort in the Joint Technical Commission for Oceanography and Marine Meteorology (JCOMM) in situ Observing Programs Support Center (JCOMMOPS) have increased the profile of, and participation in, the program and led to increased data use for a range of efforts. In addition to scientific discovery, GO-SHIP provides climate quality observations for ongoing calibration of measurements from existing and new autonomous platforms. This includes biogeochemical observations for the nascent array of biogeochemical (BGC)-Argo floats; temperature and salinity for Deep Argo; and salinity for the core Argo array. GO-SHIP provides the relevant suite of global, full depth, high quality observations and co-located deployment opportunities that, for the foreseeable future, remain crucial to maintenance and evolution of Argo's unique contribution to climate science. The evolution of GO-SHIP from a program primarily focused on physical climate to increased emphasis on ocean health and sustainability has put an emphasis on the addition of essential ocean variables for biology and ecosystems in the program measurement suite. In conjunction with novel automated measurement systems, ocean color, particulate matter, and phytoplankton enumeration are being explored as GO-SHIP variables. The addition of biological and ecosystem measurements will enable GO-SHIP to determine trends and variability in these key indicators of ocean health. The active and adaptive community has sustained the network, quality and relevance of the global repeat hydrography effort through societally important scientific results, increased exposure, and interoperability with new efforts and opportunities within the community. Here we provide key recommendations for the continuation and growth of GO-SHIP in the next decade.

Shi, JR, Xie SP, Talley LD.  2018.  Evolving relative importance of the Southern Ocean and North Atlantic in anthropogenic ocean heat uptake. Journal of Climate. 31:7459-7479.   10.1175/jcli-d-18-0170.1   AbstractWebsite

Ocean uptake of anthropogenic heat over the past 15 years has mostly occurred in the Southern Ocean, based on Argo float observations. This agrees with historical simulations from phase 5 of the Coupled Model Intercomparison Project (CMIP5), where the Southern Ocean (south of 30 degrees S) accounts for 72% +/- 28% of global heat uptake, while the contribution from the North Atlantic north of 30 degrees N is only 6%. Aerosols preferentially cool the Northern Hemisphere, and the effect on surface heat flux over the subpolar North Atlantic opposes the greenhouse gas (GHG) effect in nearly equal magnitude. This heat uptake compensation is associated with weakening (strengthening) of the Atlantic meridional overturning circulation (AMOC) in response to GHG (aerosol) radiative forcing. Aerosols are projected to decline in the near future, reinforcing the greenhouse effect on the North Atlantic heat uptake. As a result, the Southern Ocean, which will continue to take up anthropogenic heat largely through the mean upwelling of water from depth, will be joined by increased relative contribution from the North Atlantic because of substantial AMOC slowdown in the twenty-first century. In the RCP8.5 scenario, the percentage contribution to global uptake is projected to decrease to 48% +/- 8% in the Southern Ocean and increase to 26% +/- 6% in the northern North Atlantic. Despite the large uncertainty in the magnitude of projected aerosol forcing, our results suggest that anthropogenic aerosols, given their geographic distributions and temporal trajectories, strongly influence the high-latitude ocean heat uptake and interhemispheric asymmetry through AMOC change.

Shcherbina, AY, Rudnick DL, Talley LD.  2005.  Ice-draft profiling from bottom-mounted ADCP data. Journal of Atmospheric and Oceanic Technology. 22:1249-1266.   10.1175/jtech1776.1   AbstractWebsite

The feasibility of ice-draft profiling using an upward-looking bottom-mounted acoustic Doppler current profiler (ADCP) is demonstrated. Ice draft is determined as the difference between the instrument depth, derived from high-accuracy pressure data, and the distance to the lower ice surface, determined by the ADCP echo travel time. Algorithms for the surface range estimate from the water-track echo intensity profiles, data quality control, and correction procedures have been developed. Sources of error in using an ADCP as an ice profiler were investigated using the models of sound signal propagation and reflection. The effects of atmospheric pressure changes, sound speed variation, finite instrument beamwidth, hardware signal processing, instrument tilt, beam misalignment, and vertical sensor offset are quantified. The developed algorithms are tested using the data from the winter-long ADCP deployment on the northwestern shelf of the Okhotsk Sea.

Shcherbina, AY, Talley LD, Rudnick DL.  2004.  Dense water formation on the northwestern shelf of the Okhotsk Sea: 1. Direct observations of brine rejection. Journal of Geophysical Research-Oceans. 109   10.1029/2003jc002196   AbstractWebsite

[1] Dense Shelf Water (DSW) formation due to brine rejection in the coastal polynya on the northwestern shelf of the Okhotsk Sea was studied using two bottom moorings during the winter of 1999 - 2000. A steady salinity and density increase that continued for over a month was observed at the shallower mooring. The maximum density of sigma(theta) = 26.92 kg m(-3) was reached during this period. The density increase terminated abruptly in late February, while the active brine rejection continued for several more weeks based on indirect evidence from water properties and ice cover. This termination was possibly due to the onset of baroclinic instability of the density front at the polynya edge facilitating offshore eddy transport of the density anomaly. Observed periodic baroclinic tide intensification events are hypothesized to be an indicator of the presence of such baroclinic eddies. No significant density increase was observed at the deeper, offshore mooring, indicating a robust demarcation of the offshore extent of newly formed DSW. The relatively fresh water of the tidally mixed zone inshore of the shelf front was the precursor of the DSW, aided by the late-autumn offshore transition of the front.

Shcherbina, AY, Talley LD, Firing E, Hacker P.  2003.  Near-surface frontal zone trapping and deep upward propagation of internal wave energy in the Japan/East Sea. Journal of Physical Oceanography. 33:900-912.   10.1175/1520-0485(2003)33<900:nfztad>2.0.co;2   AbstractWebsite

The full-depth current structure in the Japan/East Sea was investigated using direct velocity measurements performed with lowered and shipboard acoustic current Doppler profilers. Rotary spectral analysis was used to investigate the three-dimensional energy distribution as well as wave polarization with respect to vertical wave-numbers, yielding information about the net energy propagation direction. Highly energetic near-inertial downward-propagating waves were found in localized patches along the southern edge of the subpolar front. Between 500- and 2500-m depth, the basin average energy propagation was found to be upward, with the maximum of relative difference between upward- and downward-propagating energy lying at about 1500-m depth. This difference was most pronounced in the southeastern part of the basin.