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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.

Feely, RA, Talley LD, Johnson GC, Sabine CL, Wanninkhof R.  2005.  Repeat hydrography cruises reveal chemical changes in the North Atlantic. Eos, Transactions American Geophysical Union. 86:399,404-405. Abstract
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, Rudnick DL.  2004.  Dense water formation on the northwestern shelf of the Okhotsk Sea: 2. Quantifying the transports. Journal of Geophysical Research-Oceans. 109   10.1029/2003jc002197   AbstractWebsite

A combination of direct bottom mooring measurements, hydrographic and satellite observations, and meteorological reanalysis was used to estimate the rate of formation of Dense Shelf Water (DSW) due to brine rejection on the Okhotsk Sea northwestern shelf and the rate of export of DSW from this region. On the basis of remote sensing data, an estimated 8.6x10(12) m(3) of DSW was formed during the winter of 1999-2000, resulting in a mean annual production rate of 0.3 Sv. According to direct observations, the export rate of DSW during this period varied from negligibly small in autumn to 0.75+/-0.27 Sv in winter (January-February), to 0.34+/-0.12 Sv in spring (March-April). From these observations the mean annual export rate can be estimated to be 0.27 Sv. The same relationships used to obtain the integral estimates were also applied differentially using an advective approach incorporating realistic flow and heat flux fields, which allowed direct comparison with the moored observations. The comparison highlights the importance of along-shelf advection and cross-shelf eddy transport to the accurate parameterization of DSW formation.

Fukamachi, Y, Mizuta G, Ohshima KI, Talley LD, Riser SC, Wakatsuchi M.  2004.  Transport and modification processes of dense shelf water revealed by long-term moorings off Sakhalin in the Sea of Okhotsk. Journal of Geophysical Research-Oceans. 109   10.1029/2003jc001906   AbstractWebsite

The region off the east coast of Sakhalin is thought of as an important pathway of dense shelf water (DSW) from its production region in the northwestern Okhotsk Sea to the southern Okhotsk Sea. From July 1998 to June 2000, the first long-term mooring experiment was carried out in this region to observe the southward flowing East Sakhalin Current (ESC) and DSW. Moored and associated hydrographic data show considerable modification of cold dense water via mixing with warm offshore water in the slope region off northern Sakhalin. Significant onshore eddy heat flux was observed at the northernmost mooring (54.9degreesN), which suggests the occurrence of baroclinic instability. The eddy heat flux was not significant farther south. At moorings along 53degreesN, cold anticyclonic eddies were identified that were consistent with isolated eddies seen in the hydrographic data. The three years of hydrographic data also showed large differences in extent and properties of DSW. Furthermore, the mooring data show that seasonal variability of DSW was quite different in the two years. The average DSW transport for sigma(theta) > 26.7 evaluated using the moored data at 53degreesN for 1 year (1998-1999) was similar to0.21 Sv (= 10(6) m(3) s(-1)). This value is at the lower end of the previous indirect estimates. Along with the DSW modification, this transport estimate indicates that DSW was not only carried southward by the ESC but was spread offshore by eddies off northern Sakhalin.

Talley, LD, Tishchenko P, Luchin V, Nedashkovskiy A, Sagalaev S, Kang DJ, Warner M, Min DH.  2004.  Atlas of Japan (East) Sea hydrographic properties in summer, 1999. Progress in Oceanography. 61:277-348.   10.1016/j.pocean.2004.06.011   AbstractWebsite

Hydrographic properties from CTD and discrete bottle sample profiles covering the Japan (East) Sea in summer, 1999, are presented in vertical sections, maps at standard depths, maps on isopycnal surfaces, and as property-property distributions. This data set covers most of the Sea with the exception of the western boundary region and northern Tatar Strait, and includes nutrients, pH, alkalinity, and chlorofluorocarbons, as well as the usual temperature, salinity, and oxygen observations. (C) 2004 Elsevier Ltd. All rights reserved.

Tishchenko, PY, Talley LD, Lobanov VB, Zhabin IA, Luchm VA, Nedashkovskii AP, Sagalaev SG, Chichkin RV, Shkirnikova EM, Ponomarev VI, Masten D, Kang DJ, Kim KR.  2003.  Seasonal variability of the hydrochemical conditions in the sea of Japan. Oceanology. 43:643-655. AbstractWebsite

In the summer of 1999 and the winter of 2000, during international expeditions of R/Vs Professor Khromov and Roger Revelle, hydrological and hydrochemical studies of the Sea of Japan were performed. Comparing the hydrochemical characteristics of the Sea of Japan in the summer and winter seasons, we have found that the seasonal variability affects not only the upper quasihomogeneous layer but also the deeper layers. This variability is caused by the intensification of vertical mixing during the winter season. It was shown that the mixing intensification in the deep layers of the sea in the winter might be caused both by the slope convection and by the deep convection in the open part of the sea, penetrating deeper than 1000 in. It was found that the area of positive values of the biological constituent of the apparent oxygen consumption coincides with the area of deep convection. The climatic zoning in the distribution of partial pressure of carbon dioxide was revealed for both seasons. In the northwestern part of the sea, carbon dioxide is released into the atmosphere due to the deep convection in the winter and the heating process in the summer. The southern part of the sea absorbs the atmospheric carbon dioxide because of the process of photosynthesis and cooling of the waters supplied from the Korea Strait.

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   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.

Alley, RB, Marotzke J, Nordhaus WD, Overpeck JT, Peteet DM, Pielke RA, Pierrehumbert RT, Rhines PB, Stocker TF, Talley LD, Wallace JM.  2003.  Abrupt climate change. Science. 299:2005-2010.   10.1126/science.1081056   AbstractWebsite

Large, abrupt, and widespread climate changes with major impacts have occurred repeatedly in the past, when the Earth system was forced across thresholds. Although abrupt climate changes can occur for many reasons, it is conceivable that human forcing of climate change is increasing the probability of large, abrupt events. Were such an event to recur, the economic and ecological impacts could be large and potentially serious. Unpredictability exhibited near climate thresholds in simple models shows that some uncertainty will always be associated with projections. In light of these uncertainties, policy-makers should consider expanding research into abrupt climate change, improving monitoring systems, and taking actions designed to enhance the adaptability and resilience of ecosystems and economies.

Talley, LD.  2003.  Shallow, intermediate, and deep overturning components of the global heat budget. Journal of Physical Oceanography. 33:530-560.   10.1175/1520-0485(2003)033<0530:siadoc>;2   AbstractWebsite

The ocean's overturning circulation and associated heat transport are divided into contributions based on water mass ventilation from 1) shallow overturning within the wind-driven subtropical gyres to the base of the thermocline, 2) overturning into the intermediate depth layer (500-2000 m) in the North Atlantic and North Pacific, and 3) overturning into the deep layers in the North Atlantic (Nordic Seas overflows) and around Antarctica. The contribution to South Pacific and Indian heat transport from the Indonesian Throughflow is separated from that of the subtropical gyres and is small. A shallow overturning heat transport of 0.6 PW dominates the 0.8-PW total heat transport at 24degreesN in the North Pacific but carries only 0.1-0.4 PW of the 1.3-PW total in the North Atlantic at 24degreesN. Shallow overturning heat transports in the Southern Hemisphere are also poleward: -0.2 to -0.3 PW southward across 30degreesS in each of the Pacific and Indian Oceans but only -0.1 PW in the South Atlantic. Intermediate water formation of 2 and 7 Sv (1 Sv = 10(6) m(3) s(-1)) carries 0.1 and 0.4 PW in the North Pacific and Atlantic, respectively, while North Atlantic Deep Water formation of 19 Sv carries 0.6 PW. Because of the small temperature differences between Northern Hemisphere deep waters that feed the colder Antarctic Bottom Water (Lower Circumpolar Deep Water), the formation of 22 Sv of dense Antarctic waters is associated with a heat transport of only -0.14 PW across 30degreesS (all oceans combined). Upwelling of Circumpolar Deep Water north of 30degreesS in the Indian (14 Sv) and South Pacific (14 Sv) carries -0.2 PW in each ocean.

Gladyshev, S, Talley L, Kantakov G, Khen G, Wakatsuchi M.  2003.  Distribution, formation, and seasonal variability of Okhotsk Sea Mode Water. Journal of Geophysical Research-Oceans. 108   10.1029/2001jc000877   AbstractWebsite

Russian historical data and recently completed conductivity-temperature-depth surveys are used to examine the formation and spread in the deep Ohkotsk Sea of dense shelf water (DSW) produced in the Okhotsk Sea polynyas. Isopycnal analysis indicates that all of the main polynyas contribute to the ventilation at sigma(theta) < 26.80, including the Okhotsk Sea Mode Water (OSMW), which has densities σ(θ) = 26.7-27.0. At densities greater than 26.9 σ(θ) the northwest polynya is the only contributor to OSMW. (Although Shelikhov Bay polynyas produce the densest water with σ(θ) > 27.1, vigorous tidal mixing leads to outflow of water with a density of only about 26.7 sigma(theta)). In the western Okhotsk Sea the East Sakhalin Current rapidly transports modified dense shelf water along the eastern Sakhalin slope to the Kuril Basin, where it is subject to further mixing because of the large anticyclonic eddies and tides. Most of the dense water flows off the shelves in spring. Their average flux does not exceed 0.2 Sv in summer and fall. The shelf water transport and water exchange with the North Pacific cause large seasonal variations of temperature at densities of 26.7-27.0 sigma(theta) (depths of 150-500 m) in the Kuril Basin, where the average temperature minimum occurs in April-May, and the average temperature maximum occurs in September, with a range of 0.2degrees-0.7degreesC. The average seasonal variations of salinity are quite small and do not exceed 0.05 psu. The Soya Water mixed by winter convection, penetrating to depths greater than 200 m, in the southern Kuril Basin also produces freezing water with density greater than 26.7 sigma(theta). Using a simple isopycnal box model and seasonal observations, the OSMW production rate is seen to increase in summer up to 2.2 +/- 1.7 Sv, mainly because of increased North Pacific inflow, and drops in winter to 0.2 +/- 0.1 Sv. A compensating decrease in temperature in the Kuril Basin implies a DSW volume transport of 1.4 +/- 1.1 Sv from February through May. The residence time of the OSMW in the Kuril Basin is 2 +/- 1.7 years.

Flatau, MK, Talley L, Niiler PP.  2003.  The North Atlantic Oscillation, surface current velocities, and SST changes in the subpolar North Atlantic. Journal of Climate. 16:2355-2369.   10.1175/2787.1   AbstractWebsite

Changes in surface circulation in the subpolar North Atlantic are documented for the recent interannual switch in the North Atlantic Oscillation (NAO) index from positive values in the early 1990s to negative values in 1995/96. Data from Lagrangian drifters, which were deployed in the North Atlantic from 1992 to 1998, were used to compute the mean and varying surface currents. NCEP winds were used to calculate the Ekman component, allowing isolation of the geostrophic currents. The mean Ekman velocities are considerably smaller than the mean total velocities that resemble historical analyses. The northeastward flow of the North Atlantic Current is organized into three strong cores associated with topography: along the eastern boundary in Rockall Trough, in the Iceland Basin ( the subpolar front), and on the western flank of the Reykjanes Ridge (Irminger Current). The last is isolated in this Eulerian mean from the rest of the North Atlantic Current by a region of weak velocities on the east side of the Reykjanes Ridge. The drifter results during the two different NAO periods are compared with geostrophic flow changes calculated from the NASA/Pathfinder monthly gridded sea surface height (SSH) variability products and the Advanced Very High Resolution Radiometer (AVHRR) SST data. During the positive NAO years the northeastward flow in the North Atlantic Current appeared stronger and the circulation in the cyclonic gyre in the Irminger Basin became more intense. This was consistent with the geostrophic velocities calculated from altimetry data and surface temperature changes from AVHRR SST data, which show that during the positive NAO years, with stronger westerlies, the subpolar front was sharper and located farther east. SST gradients intensified in the North Atlantic Current, Irminger Basin, and east of the Shetland Islands during the positive NAO phase, associated with stronger currents. SST differences between positive and negative NAO years were consistent with changes in air-sea heat flux and the eastward shift of the subpolar front. SST advection, as diagnosed from the drifters, likely acted to reduce the SST differences.

Talley, LD, Lobanov V, Ponomarev V, Salyuk A, Tishchenko P, Zhabin I, Riser S.  2003.  Deep convection and brine rejection in the Japan Sea. Geophysical Research Letters. 30   10.1029/2002gl016451   AbstractWebsite

Direct water mass renewal through convection deeper than 1000 m and the independent process of dense water production through brine rejection during sea ice formation occur at only a limited number of sites globally. Our late winter observations in 2000 and 2001 show that the Japan (East) Sea is a part of both exclusive groups. Japan Sea deep convection apparently occurs every winter, but massive renewal of bottom waters through brine rejection had not occurred for many decades prior to the extremely cold winter of 2001. The sites for both renewal mechanisms are south of Vladivostok, in the path of cold continental air outbreaks.

Shcherbina, AY, Talley LD, Rudnick DL.  2003.  Direct observations of North Pacific ventilation: Brine rejection in the Okhotsk Sea. Science. 302:1952-1955.   10.1126/science.1088692   AbstractWebsite

Brine rejection that accompanies ice formation in coastal polynyas is responsible for ventilating several globally important water masses in the Arctic and Antarctic. However, most previous studies of this process have been indirect, based on heat budget analyses or on warm-season water column inventories. Here, we present direct measurements of brine rejection and formation of North Pacific Intermediate Water in the Okhotsk Sea from moored winter observations. A steady, nearly linear salinity increase unambiguously caused by local ice formation was observed for more than a month.

Yun, JY, Talley LD.  2003.  Cabbeling and the density of the North Pacific Intermediate Water quantified by an inverse method. Journal of Geophysical Research-Oceans. 108   10.1029/2002jc001482   AbstractWebsite

North Pacific Intermediate Water (NPIW), defined as the main salinity minimum in the subtropical North Pacific, at a density of 26.7-26.8sigma(theta), is denser than the winter surface water in the Oyashio which is the source of the salinity minimum. We showed previously that cabbeling and double diffusion during mixing between the Oyashio water and more saline Kuroshio water can account for the density increase from the surface source water to the salinity minimum. An inverse method is employed herein to quantify the effect of cabbeling, using CTD data from the western North Pacific. The difference between proportional mixing between parcels of Oyashio and Kuroshio waters and mixing along isopycnals is exploited to compute the convergence of water into density layers. The diapycnal transport convergence associated with cabbeling into the NPIW density layer is estimated to be 0.56 Sv for an assumed turnover time of 1 year in the region between 142degreesE and 152degreesE. Diapycnal transport convergences in the regions 152degreesE-165degreesE, 165degreesE-175degreesW, and 175degreesW-136degreesW are similarly estimated by assuming longer turnover times. We estimate that the total diapycnal transport convergence into the NPIW density layer may be up to 2.3 Sv in the entire NPIW region.

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   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.

Tishchenko, PY, Talley LD, Nedashkovskii AP, Sagalaev SG, Zvalinskii VI.  2002.  Temporal variability of the hydrochemical properties of the waters of the Sea of Japan. Oceanology. 42:795-803. AbstractWebsite

Hydrochemical studies were performed in the Sea of Japan from onboard R/V Akademik Vinogradov in 1992 and R/Vs Roger Revelle and Professor Khromov in 1999. A comparison of the hydrochemical properties (concentrations of dissolved oxygen and nutrients and proteins of the carbonate system) of the waters of the Sea of Japan with those of the adjacent basins (the Sea of Okhotsk, Pacific Ocean, and East China Sea) demonstrates significant differences between them. In addition, a significant temporal variability of the hydrochemical properties of the intermediate and abyssal waters of the Sea of Japan was revealed. A general increase in the contents of inorganic forms of phosphorus, nitrogen, and normalized organic matter along with a general decrease in the oxygen concentration and normalized alkalinity with time was established. We suggest a model for an open basin, in which the principal reason for the observed features and temporal variability of the hydrochemical properties is related to the water exchange between the Sea of Japan and adjacent basins. A supposition is posed on the strong dependence of the water exchange on the variability of the intensity analysis direction of the major currents of the northwestern Pacific Ocean, especially the Kuroshio Current.

Gordon, AL, Giulivi CF, Lee CM, Furey HH, Bower A, Talley L.  2002.  Japan/East Sea intrathermocline eddies. Journal of Physical Oceanography. 32:1960-1974.   10.1175/1520-0485(2002)032<1960:jesie>;2   AbstractWebsite

Intrathermocline eddies (ITE) with diameters of 100 km and of thickness greater than 100 m are observed within each of the three quasi-stationary meanders of the Tsushima Current of the Japan/East Sea. Within the ITE homogenous, anticyclonic flowing core, the temperature is near 10degreesC with a salinity of 34.12 psu. Because of compensatory baroclinicity of the upper and lower boundaries of the ITE core, the ITE has minor sea level expression. The ITE core displays positive oxygen and negative salinity anomalies in comparison to the surrounding thermocline water, indicative of formation from winter mixed layer water along the southern side of the Japan/East Sea subpolar front. The winter mixing layer is then overridden, or slips below, the regional upper thermocline stratification with its characteristic salinity maximum layer. The winter mixed layer off the coast of Korea closely matches the ITE core characteristics, and is considered as a potential source region. Other sources may be present along the southern boundary of the subpolar front, including a frequently observed warm eddy over the western side of Yamato Rise.

Hanawa, K, Talley LD.  2001.  Mode Waters. Ocean circulation and climate : observing and modelling the global ocean. ( Siedler G, Church J, Gould WJ, Eds.).:373-386., San Diego, Calif. London: Academic Abstract
Talley, LD, Yun JY.  2001.  The role of cabbeling and double diffusion in setting the density of the North Pacific intermediate water salinity minimum. Journal of Physical Oceanography. 31:1538-1549.   10.1175/1520-0485(2001)031<1538:trocad>;2   AbstractWebsite

The top of the North Pacific Intermediate Water (NPIW) in the subtropical North Pacific is identified with the main salinity minimum in the density range sigma (theta) = 26.7-26.8. The most likely source of low salinity for the NPIW salinity minimum is the Oyashio winter mixed layer, of density sigma (theta) = 26.5- 26.65. The Oyashio waters mix with Kuroshio waters in the broad region known as the Mixed Water Region (MWR), between the separated Kuroshio and Oyashio Fronts just east of Japan. It is shown that cabbeling during mixing of the cold, fresh Oyashio winter mixed layer water with the warm, saline Kuroshio water increases the density of the mixture by up to sigma (theta) = 0.07 at densities around sigma (theta) = 26.6-26.65, regardless of the mixing mechanism. Thus cabbeling accounts for about half of the observed density difference between the Oyashio winter mixed layer water and the top of the NPIW. Double diffusion during mixing of the interleaving layers of Oyashio and Kuroshio waters in the MWR can also change the density of the mixing intrusions. Density ratios favorable to double diffusion are shown to be especially prominent in Oyashio intrusions into a Kuroshio warm core ring in the 1989 data examined here. The average potential temperature-salinity profile of the new subtropical NPIW just east of the MWR, with its nearly uniform salinity, suggests the dominance of salt fingering over diffusive layering. Using the observed salinity and density differences between Oyashio surface water and the NPIW salinity minimum, after subtracting the density difference ascribed to cabbeling, an effective flux ratio of about 0.8 is estimated for possible double diffusive processes in the MWR.

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
Flatau, M, Talley L, Musgrave D.  2000.  Interannual variability in the Gulf of Alaska during the 1991-94 El Nino. Journal of Climate. 13:1664-1673.   10.1175/1520-0442(2000)013<1664:ivitgo>;2   AbstractWebsite

Mass and heat budgets in the Gulf of Alaska during the 1991-94 El Nino are examined using hydrographic data from several cruises undertaken as part of the International North Pacific Ocean Climate program and the repeated Canadian hydrographic sections out to Ocean weather Station Papa. The geostrophic ocean circulation resulted in convergence of heat into the region in spring 1992 and spring 1993. The advective heat convergence in spring 1992 corresponded to an average surface heat flux from the ocean to the atmosphere of about 74 W m(-2) in comparison with only 30 W m(-2) during spring 1993. The larger ocean heat loss to the atmosphere in 1992 followed a winter of large tropical SST anomalies and anomalously low pressure in the Aleutian low.

McCarthy, MC, Talley LD, Roemmich D.  2000.  Seasonal to interannual variability from expendable bathythermograph and TOPEX/Poseidon altimeter data in the South Pacific subtropical gyre. Journal of Geophysical Research-Oceans. 105:19535-19550.   10.1029/2000jc900056   AbstractWebsite

Estimates of dynamic height anomalies from expendable bathythermograph (XBT) and TOPEX/Poseidon (T/P) sea surface height (SSH) measurements were compared along a, transect at similar to 30 degrees S in the South Pacific. T/P SSH anomalies were calculated relative to a 5 year time mean. XBT dynamic height was calculated relative to 750 m using measured temperature and an objectively mapped climatological temperature-salinity relationship. The anomaly was obtained by subtracting out an objectively-mapped climatological dynamic height relative to 750 m. XBT temperature sections show evidence of a double-gyre structure, related to changes in shallow isopycnals near the gyre's center. XBT dynamic height and T/P SSH anomalies compare well with an RMS difference of 3.8 cm and a coherence above 0.7 for scales larger than 300 km. The differences between the two measures of dynamic height yield systematic patterns. Time-varying spatial averages of the differences are found to be related to changes in Sverdrup transport, zonal surface slope differences, and the 6 degrees C isotherm depth. Higher zonally averaged altimetry SSH than zonally averaged XBT height and larger northward transport from altimetry SSH than from XBT height correspond to gyre spinup determined from Sverdrup transport changes. This implies mass storage during gyre spinup due to the phase lag between the Ekman pumping and the full baroclinic Sverdrup response. Increases in the spatially averaged differences and zonal slope differences, associated with gyre spinup, correspond to shoaling in the 6 degrees C isotherm depth, requiring deep baroclinic changes out of phase with the 6 degrees C isotherm depth changes.

McCarthy, MC, Talley LD.  1999.  Three-dimensional isoneutral potential vorticity structure in the Indian Ocean. Journal of Geophysical Research-Oceans. 104:13251-13267.   10.1029/1999jc900028   AbstractWebsite

The three-dimensional isoneutral potential vorticity structure of the Indian Ocean is examined using World Ocean Circulation Experiment and National Oceanic and Atmospheric Administration conductivity-temperature-depth data and historical bottle data. The distribution of the potential vorticity is set by the Indian Ocean's source waters and their circulation inside the basin. The lower thermocline has a high potential vorticity signal extending westward from northwest of Australia and a low signal from the Subantarctic Mode Water in the south. The Antarctic Intermediate Water inflow creates patches of high potential vorticity at intermediate depths in the southern Indian Ocean, below which the field becomes dominated by planetary vorticity, indicating a weaker meridional circulation and weaker potential vorticity sources. Wind-driven gyre depths have lower potential vorticity gradients primarily due to same-source waters. Homogenization and western shadow zones are not observed. The P-effect dominates the effect of the Somali Current and the Red Sea Water on the potential vorticity distribution. Isopleths tilt strongly away from latitude lines in the deep and abyssal waters as the Circumpolar Deep Water fills the basins in deep western boundary currents, indicating a strong meridional circulation north of the Antarctic Circumpolar Current. The lower-gradient intermediate layer surrounded vertically by layers with higher meridional potential vorticity gradients in the subtropical Indian Ocean suggests that Rossby waves will travel similar to 1.3 times faster than standard theory predicts. To the south, several pools of homogenized potential vorticity appear in the upper 2000 m of the Southern Ocean where gyres previously have been identified. South of Australia the abyssal potential vorticity structure is set by a combination of the Antarctic Circumpolar Current and the bathymetry.

Talley, LD.  1999.  Simple coupled midlatitude climate models. Journal of Physical Oceanography. 29:2016-2037.   10.1175/1520-0485(1999)029<2016:scmcm>;2   AbstractWebsite

A set of simple analytical models is presented and evaluated for interannual to decadal coupled ocean-atmosphere modes at midlatitudes. The atmosphere and ocean are each in Sverdrup balance at these long timescales. The atmosphere's temperature response to heating determines the spatial phase relation between SST and sea level pressure (SLP) anomalies. Vertical advection balancing heating produces high (low) SLP lying east of warm (cold) SST anomalies, as observed in the Antarctic circumpolar wave (ACW), the decadal North Pacific mode, and the interannual North Atlantic mode. Zonal advection in an atmosphere with a rigid lid produces low SLP east of warm SST. However, if an ad hoc equivalent barotropic atmospheric response is assumed, high SLP lies east of warm SST. Relaxation to heating produces behavior like the observed North Atlantic decadal pattern, with low SLP over warm SST. Meridional advection in the atmosphere cannot produce the observed SST/SLP patterns. The dominant balance in the oceans temperature equation determines the phase speed of the modes. The coupled mode is nondispersive in all models examined here, indicating the need for additional processes. For modes with an SST-SLP offset as observed in the ACW and North Pacific, Ekman convergence acting as a heat source causes eastward propagation relative to the mean ocean flow. Sverdrup response to Ekman convergence, acting on the mean meridional temperature gradient, causes westward propagation relative to the mean ocean Row. When the ocean temperature adjusts through surface heat flux alone, the mode is advected by the mean ocean flow and is damped. Relaxation to heating in the atmosphere, when operating with Sverdrup response in the ocean, produces the only complete solution presented here that exhibits growth, with an a-folding timescale of order (100 days). This solution appears appropriate for the North Atlantic decadal mode. In Northern Hemisphere basins, with meridional boundaries, the: same sets of dynamics create the observed SST-SLP phase relation. An additional factor is the creation of SST anomalies through variations in the western boundary current strengths, which are related to the zonally integrated wind stress curl over the whole basin. If barotropic and hence fast adjustment is assumed, the resulting positive feedback can maintain or strengthen the coupled anomalies in the North Pacific and interannual North Atlantic modes.