Climate-driven variability of the Southern Ocean CO2 sink.

The Southern Ocean is a major sink of atmospheric CO2, but the nature and magnitude of its variability remains uncertain and debated. Estimates based on observations suggest substantial variability that is not reproduced by process-based ocean models, with increasingly divergent estimates over the past decade. We examine potential constraints on the nature and magnitude of climate-driven variability of the Southern Ocean CO2 sink from observation-based air-sea O2 fluxes. On interannual time scales, the variability in the air-sea fluxes of CO2 and O2 estimated from observations is consistent across the two species and positively correlated with the variability simulated by ocean models. Our analysis suggests that variations in ocean ventilation related to the Southern Annular Mode are responsible for this interannual variability. On decadal time scales, the existence of significant variability in the air-sea CO2 flux estimated from observations also tends to be supported by observation-based estimates of O2 flux variability. However, the large decadal variability in air-sea CO2 flux is absent from ocean models. Our analysis suggests that issues in representing the balance between the thermal and non-thermal components of the CO2 sink and/or insufficient variability in mode water formation might contribute to the lack of decadal variability in the current generation of ocean models. This article is part of a discussion meeting issue 'Heat and carbon uptake in the Southern Ocean: the state of the art and future priorities'.

Casimir light: field pressure.

The electromagnetic field is assigned a self-consistent role in which abrupt slowing of the collapse produces radiation and the pressure of the radiation produces abrupt slowing. A simple expression is introduced for the photon spectrum. Conditions for light emission are proposed that imply a high degree of spatial localization. Some numerical checks are satisfied. A study of the mechanical equations of motion suggests an explanation of the very short time scale in terms of oppositely directed field pressures and the speed of light.

Casimir light: pieces of the action.

More realistic dynamics for the collapsing dielectric fluid are introduced in stages by adding contributions to the Lagrangian that forms the action. The elements are kinetic energy, Casimir potential energy, air pressure potential energy, and electromagnetic coupling to the moving dielectric. There are successful tests of partial collapse time and of minimum radius.

Casimir light: photon pairs.

Expressions are developed for weak single pair emission probability and strong emission average number of pairs. The water transparency cutoff is closely realized, showing that the fundamental time scale is even shorter.

Casimir light: the source.

The release of Casimir energy in filling a dielectric hole is identified as the source of coherent sonoluminescence. Qualitative agreement with recently acquired data is found for the magnitude and shape of the spectrum.

Casimir light: a glimpse.

Light emission produced by the reversible collapse of a cavity in a dielectric medium is given an initial, simplified treatment. The agreement between planar and spherical shapes indicates the volume nature of the effect.

Casimir energy for dielectrics: spherical geometry.

An expression is produced for the Casimir energy of a dielectric medium with a spherically symmetrical dielectric discontinuity. Tests based on dielectric and geometrical limits are successful.

Casimir energy for dielectrics.

A treatment in terms of two scalar fields supplies the electromagnetic energy of attraction between two similar dielectric slabs with parallel plane interfaces.

Phonon Green's function.

The concepts of source and quantum action principle are used to produce the phonon Green's function appropriate for an initial phonon vacuum state. An application to the Mossbauer effect is presented.

Phonon dynamics.

An atomic lattice in its ground state is excited by the rapid displacement and release of an atomic constituent. The time dependence of the energy transfer to other constituents is studied by using a phonon dispersion relation that is linear in frequency and propagation vector components.

Phonon representations.

The gap between the nonlocalized lattice-phonon description and the localized Einstein oscillator treatment is filled by transforming the phonon Hamiltonian back to the particle variables. The particle-coordinate, normalized, wave function for the phonon vacuum state is exhibited.

Deep inelastic scattering of charged leptons.

The concept of a model based on the hypothesis of smooth extrapolation rather than explicit dynamical speculation is expounded. The existing body of successful applications is extended to the longitudinal cross section in deep inelastic scattering, and predictions are made for the asymmetry in scattering of polarized electrons on polarized protons.

Deep inelastic scattering of leptons.

The description of deep inelastic scattering as an extrapolation between resonance production and diffractive scattering is extended to give successful quantitative representations for the structure functions of unpolarized electron scattering on protons and neutrons, and of neutrino, antineutrino scattering on nucleons. The same ideas also supply a prediction for the polarization asymmetry in deep inelastic electron-proton scattering (paper no. 2, to be published).

Source theory analysis of electron-positron annihilation experiments.

The phenomenological viewpoint already applied to deep inelastic scattering is extended to the discussion of electron-positron annihilation experiments. Some heuristic arguments lead to simple forms for the pion differential cross section that are in reasonable accord with the published experimental data in the energy interval 3-4.8 Gev.