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James C. Stephens and David P. Marshall

1. Introduction A tongue of warm and salty water known as the Mediterranean salinity tongue (MST) is the most prominent feature of the North Atlantic at middepths. It sets the temperature–salinity structure of a large part of the interior ocean in this region. Figure 1 shows salinity on potential density surfaces σ 1 = 31.85 (depth ∼ 600 m at the eastern boundary, the upper limit of the MST) and σ 1 = 32.35 (depth ∼ 1500 m). On σ 1 = 31.85 there is a pronounced northward as well as a

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Alberto Troccoli, Magdalena Alonso Balmaseda, Joachim Segschneider, Jerome Vialard, David L. T. Anderson, Keith Haines, Tim Stockdale, Frederic Vitart, and Alan D. Fox

assimilated. Not much attention has been given to salinity in the context of temperature data assimilation for seasonal climate forecasts. Hitherto, the most common approach has been to leave the salinity field unmodified when updating the temperature field. This is partly because subsurface salinity observations available in near–real time are very sparse, and partly because the salinity field was thought to be of less importance for the density in the upper tropical ocean. However we will show that not

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Parker MacCready

1. Introduction Estuarine circulation and salinity patterns are the result of several competing factors: river flow pushes seaward, denser ocean water slides landward, and tidal currents stir and mix the two. In particular, the “exchange flow” or “gravitational circulation,” with deep inflow and shallow outflow, dominates the circulation structure of many estuaries. We have sought to understand this complex system in part by tidal averaging. Theories have been developed to predict the subtidal

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Gaël Forget and Carl Wunsch

instantaneous temperature and salinity observations in least squares fitting problems that focus on the large-scale ocean state [e.g., Estimating the Circulation and Climate of the Ocean (ECCO); Wunsch and Heimbach (2006) ]. 2. Sources of information, hypotheses, and methodology We start from a set of sample variances, computed by Stephens et al. (2002) using “historical” data. Here p indexes groups of values; each group is the ensemble of measurements [of temperature ( T ) or salinity ( S )] collected

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Fabien Roquet, Jean-Benoit Charrassin, Stephane Marchand, Lars Boehme, Mike Fedak, Gilles Reverdin, and Christophe Guinet

oceanographers in the form of vertical profiles of temperature and salinity using a miniaturized conductivity–temperature–depth (CTD) cell ( Fedak 2004 ; Boehme et al. 2009 ). Fig . 1. CTD–SRDL deployed on a southern elephant seal. An additional VHF tracking device is attached on the back. Southern elephant seals ( Mirounga leonina ) are excellent candidates for the deployment of these new loggers. These top predators dive nearly continuously and to great depths ( Hindell et al. 1992 ). Moreover, they

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Gregory C. Johnson, John M. Toole, and Nordeen G. Larson

1. Introduction Salinity, temperature, and pressure are three basic-state variables that allow for the computation of ocean density and the associated physical properties of seawater. Temperature and pressure are generally measured directly, but salinity is usually calculated from these two variables together with conductivity. Such is the case with data acquired with a conductivity–temperature–depth (CTD) instrument, one of the observational mainstays of oceanography today. In many Sea

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Bruce A. Warren

1. Introduction In stationary conditions at a level sea surface, the vertical velocity ( w ) that is induced by evaporation ( E ) and precipitation ( P ) is nearly ( E − P ). In recognition that the mass flux into (or out of) the atmosphere is of freshwater alone, attempts have been made to improve the representation: w = ( E − P )/(1 − S ), where S is the mass-fraction salinity, at the sea surface (e.g., Schmitt et al. 1989 ); or w = ρ F ( E − P )/[ ρ (1 − S )], where ρ is

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Neill S. Cooper

VOLUME 18 JOURNAL OF PHYSICAL OCEANOGRAPHY MAY 1988The Effect of Salinity on Tropical Ocean Models NEILL S. COOPERThe Hooke Institute for Atmospheric Research, Clarendon Laboratory, Parks Road, Oxford, UK(Manuscript received 30 June 1987, in final form 23 October 1987)ABSTRACT The effect of horizontal salinity gradients on the tropical ocean cimulation has not previously been

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Ayan H. Chaudhuri, Avijit Gangopadhyay, and James J. Bisagni

attributed to Ekman drifts related to stronger westerlies in positive NAO phases. Lohmann et al. (2009) investigate the strength of the SPG to persistent positive and negative NAO forcing and indicate a nonlinear response. NAO-induced salinity changes in the eastern SPG ( Herbaut and Houssais 2009 ) show that salinity anomalies are mainly driven by local wind stress. Furthermore, Reverdin (2010) examines 115 yr of measurements from the northeast North Atlantic and finds a significant correlation

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Jonathan D. Nash and James N. Moum

salt fluxes, this has been a necessary assumption because it has not been possible to directly measure the turbulent flux of salt or the dissipation rate of salinity variance. It is well known that double-diffusive processes transport heat and salt at different rates ( Schmitt 1979 ). The unique dynamics associated with these structures are a direct consequence of the large value of the ratio D T / D S ≃ 100, but only occur when turbulence is weak and for a limited range of dT / dS. Having

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