Maintenance and broadening of the ocean’s salinity distribution by the water cycle

The global water cycle leaves an imprint on ocean salinity through evaporation and precipitation. It has been proposed that observed changes in salinity can be used to infer changes in the water cycle. Here salinity is characterized by the distribution of water masses in salinity coordinates. Only mixing and sources and sinks of freshwater and salt can modify this distribution. Mixing acts to collapse the distribution, making saline waters fresher and fresh waters more saline. Hence, in steady state, there must be net precipitation over fresh waters and net evaporation over saline waters. A simple model is developed to describe the relationship between the breadth of the distribution, the water cycle, and mixing—the latter being characterized by an e-folding time scale. In both observations and a state-of-the-art ocean model, the water cycle maintains a salinity distribution in steady state with a mixing time scale of the order of 50 yr. The same simple model predicts the response of the salinity distribution to a change in the water cycle. This study suggests that observations of changes in ocean salinity could be used to infer changes in the hydrological cycle

Changes in ocean vertical heat transport with global warming

Heat transport between the surface and deep ocean strongly influences transient climate change. Mechanisms setting this transport are investigated using coupled climate models and by projecting ocean circulation into the temperature-depth diagram. In this diagram, a “cold cell” cools the deep ocean through the downwelling of Antarctic waters and upwelling of warmer waters and is balanced by warming due to a “warm cell,” coincident with the interhemispheric overturning and previously linked to wind and haline forcing. With anthropogenic warming, the cold cell collapses while the warm cell continues to warm the deep ocean. Simulations with increasingly strong warm cells, set by their mean Southern Hemisphere winds, exhibit increasing deep-ocean warming in response to the same anthropogenic forcing. It is argued that the partition between components of the circulation which cool and warm the deep ocean in the preindustrial climate is a key determinant of ocean vertical heat transport with global warming

The representation of ocean circulation and variability in thermodynamic coordinates

The ocean’s circulation is analyzed in Absolute Salinity SA and Conservative Temperature ? coordinates. It is separated into 1) an advective component related to geographical displacements in the direction normal to SA and ? isosurfaces and 2) into a local component, related to local changes in SA–? values, without a geographical displacement. In this decomposition, the sum of the advective and local components of the circulation is equivalent to the material derivative of SA and ?. The sum is directly related to sources and sinks of salt and heat. The advective component is represented by the advective thermohaline streamfunction . After removing a trend, the local component can be represented by the local thermohaline streamfunction . Here, can be diagnosed using a monthly averaged time series of SA and ? from an observational dataset. In addition, and are determined from a coupled climate model. The diathermohaline streamfunction is the sum of and and represents the nondivergent diathermohaline circulation in SA–? coordinates. The diathermohaline trend, resulting from the trend in the local changes of SA and ?, quantifies the redistribution of the ocean’s volume in SA–? coordinates over time. It is argued that the diathermohaline streamfunction provides a powerful tool for the analysis of and comparison among ocean models and observation-based gridded climatologies

The Atmospheric General Circulation in Thermodynamical Coordinates

The zonal and meridional components of the atmospheric general circulation are used to define a global thermodynamic streamfunction in dry static energy versus latent heat coordinates. Diabatic motions in the tropical circulations and fluxes driven by midlatitude eddies are found to form a single, global thermodynamic cycle. Calculations based on the Interim European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-Interim) dataset indicate that the cycle has a peak transport of 428 Sv (Sv ? 109 kg s?1). The thermodynamic cycle encapsulates a globally interconnected heat and water cycle comprising ascent of moist air where latent heat is converted into dry static energy, radiative cooling where dry air loses dry static energy, and a moistening branch where air is warmed and moistened. It approximately follows a tropical moist adiabat and is bounded by the Clausius–Clapeyron relationship for near-surface air. The variability of the atmospheric general circulation is related to ENSO events using reanalysis data from recent years (1979–2009) and historical simulations from the EC-Earth Consortium (EC-Earth) coupled climate model (1850–2005). The thermodynamic cycle in both EC-Earth and ERA-Interim widens and weakens with positive ENSO phases and narrows and strengthens during negative ENSO phases with a high correlation coefficient. Weakening in amplitude suggests a weakening of the large-scale circulation, while widening suggests an increase in mean tropical near-surface moist static energy

Varia

Le langage, l’espace public, la méthode, thèmes prégnants de ce numéro varia. La comparaison des classiques confucéens et des cosmogonies périphériques, telle celle des Hani dans la province du Yunnan, soulève d’abord la question des influences réciproques entre différentes constructions mythologiques que l’Empire du Milieu a mises en contact. L’analyse rhétorique vient ensuite éclairer les enjeux de la concurrence au salut des âmes que se livrent les voix catholiques, protestantes et musulmanes dans la Haute-Volta coloniale (aujourd’hui Burkina Faso). Les mots mêmes sont des êtres qui font agir au-delà du sens qu’ils véhiculent comme le rappelle l’examen d’un débat scolastique dans la chrétienté médiévale. Enfin, l’attention portée aux gestes, comme c’est le cas pour l’étude de certaines salutations cérémonielles au Brésil, met à jour leur force de lien. Dans une perspective de science politique, sont ensuite décrits le rôle joué par la philanthropie bouddhiste dans l’action sociale de la Chine contemporaine ainsi qu’en Italie l’émergence d’un islam national s’ancrant dans les collectivités locales. Deux réflexions de nature méthodologique et épistémologique ferment la marche : l’une sur la mesure quantitative des pratiques religieuses en Suisse; l’autre sur les limites de l’analogie religieuse dans l’approche de la célébrité publique. Un petit dossier thématique s’adjoint à cette livraison par un retour sur Thérèse de Lisieux comme figure littéraire (Theresiana). La jeune sainte carmélite fut-elle en effet une écrivaine, progressivement enfouie par le procès de sa sanctification ? Cette forte hypothèse, développée par Claude Langlois dans de nombreux ouvrages, est ici présentée, discutée et accompagnée par d’autres approches d’une expérience d’écriture féminine conventuelle à l’époque du Modernisme catholique

Les archives de la mise en scène

Longtemps méprisés, les spectacles populaires sont abordés ici sous l'angle d’une culture médiatique dont on suit l’essor à travers différentes formes de spectacles visuels et sonores, théâtre, cinéma, music-hall ou café-concert. Ce volume, Spectacles populaires et culture médiatique, s’inscrit dans la continuité du précédent ouvrage publié dans la même collection, Hypermédialités du théâtre. Les dix-neuf contributions que renferme le présent volume poursuivent l’analyse des archives du fonds de l’Association de la Régie Théâtrale (ART), déposé à la Bibliothèque Historique de la Ville de Paris. Peu étudiée jusqu’ici, cette riche collection rassemble les documents – près de 6 500 pour la période choisie – déposés par les régisseurs, metteurs en scène et directeurs de théâtre de la région parisienne : relevés de mise en scène, photographies, partitions, articles de presse… Une grande partie de ce fonds concerne des œuvres traditionnellement rangées dans la catégorie des spectacles populaires.Long despised by the critics, popular shows are studied in this book as a media culture evolving through different forms of aural and visual representations, theatre, cinema, music-hall and others, often with a hypermediatic dimension