Showing papers on "Hydrostatic equilibrium published in 1968"

On the intensity of the general circulation of the atmosphere

Abstract: The intensity of the general circulation can be measured by the generation of available potential energy, the conversion of available potential energy to kinetic energy, or the dissipation of kinetic energy by frictional forces. Various estimates of the intensity are reviewed with special emphasis on the assumptions made in each investigation. There is a difference in principle between a nonhydrostatic and a hydrostatic system. In a hydrostatic system the internal and potential energies are proportional to each other, although the potential energy communicates directly with reservoirs of kinetic energy in a nonhydrostatic atmosphere. The review of the concept of available potential energy shows that the approximate form is exact for a quasi-geostrophic formulation of atmospheric dynamics. A critical evaluation is made of the generation of available potential energy and the dissipation of kinetic energy.

The dynamical state of the interstellar gas and field. V - Reduced dynamical equations.

Abstract: Interstellar gas suspended on horizontal magnetic field, obtaining results for hydrostatic equilibrium and small perturbations of equilibrium by simplifying dynamical equations

A Re-Evaluation of the Theory for the Hydrostatic Figure of the Earth

Abstract: The classical equations of de Sitter for the hydrostatic figure of the earth are modified to make their development independent of the external potential theory. The modification is essential to demonstrate clearly the correct structure of the problem of hydrostatic equilibrium for the earth. An expression is obtained giving the hydrostatic flattening in terms of other parameters, which seems to have the advantage of easy numerical manipulation. If J and H of the hydrostatic earth are taken to be equal to those determined observationally for the real earth and only the hydrostatic equations are used (as advocated by most of the post-satellite investigators), the value of hydrostatic flattening obtained is 1/296.70 ± 0.05, in contrast to the value of 1/299.86 as found from de Sitter's equations. Of course, it is possible to obtain the value of 1/299.86 for hydrostatic flattening, but the approach involved is different from the approach advocated in most of the recent investigations. It is not our intention to prove that the value of hydrostatic flattening reported in this paper is necessarily the correct value but to show that if the presently accepted method of computing hydrostatic flattening is adopted the value will be 1/296.70 ± 0.05.

Some large‐scale features of the vertical distribution of atmospheric ozone associated with the thermal structure of the atmosphere

Abstract: Ten-case running means of the vertical distributions of hydrostatic stability and of the vertical fractional gradient of the partial pressure of ozone computed from ozone and temperature soundings arranged according to tropopause height are presented for four stations located in different latitudes. It is shown that the characteristic large-scale features of the vertical distributions of the vertical ozone gradient correspond closely to similar characteristic large-scale features of the thermal structure of the atmosphere depicted by the vertical distributions of the hydrostatic stability. The layer structure of the ozone gradient and of the hydrostatic stability both show characteristic features that vary significantly with latitude and with the height of the tropopause.

On the Equilibrium Figure of the Earth

Abstract: If de Sitter's hydrostatic equations are developed independent of the external potential theory, the hydrostatic geopotential coefficient J(sub h) occurs explicitly on the right-hand side of those equations. J(sub h) here has to be treated as an unknown in the solution, it becomes rather difficult to solve the equations independently, regardless of which of the dynamical parameters associated with the earth is taken as the initial datum. Solution is possible, however, with the help of a boundary condition derived from the external potential theory which neither assumes nor discounts the presence of equilibrium conditions in the earth's interior. If a general solution i s constructed on this basis, the three particular solutions, usually quoted in literature, stem from it in the wake of the appropriate assumptions. Of course, the only meaningful solution--of these-- is that corresponding to the polar moment of inertia as the initial datum. It is essential that the solution be constructed in this way in order to demonstrate clearly the correct structure of the problem of hydrostatic equilibrium. The anomalous gravity field of the earth referred to the hydrostatic figure is compared with that referred to the international reference ellipsoid.

Temperature Measurement under Pressure

Abstract: One of the major problems in research in the area of high pressure has been the lack of an accurate and reliable method for continuous and simultaneous in situ evaluation of true pressure and temperature. Up to now, most of the temperature sensors have been developed for use at atmospheric pressure. On the other hand pressure calibration is difficult at temperatures far from room temperature, for instance close to absolute zero. The problem of temperature measurement in high pressure experiments has become more acute with the development of internally heated pressure cells. The great majority of sensors developed for use under pressure have been thermocouples, whose small size makes them suitable for high pressure experiments, even if such techniques are not free of problems as we will see. In the measurement of temperature at high pressure the biggest additional difficulty arises from the fact that it is difficult to get truly hydrostatic conditions; most of the high temperature, high pressure cells are composed of materials like levastone, talc or graphite which do not permit a close approximation to hydrostatic conditions.

Total potential energy of finite columns

Abstract: The relation between enthalpy and total potential energy in a column of finite horizontal extent is investigated. The limitations of the quasistatic approximation are introduced a priori rather than a posteriori , i.e., cyclone-scale air masses are assumed to be in hydrostatic equilibrium, but any differential equation implying small-scale hydrostatic balance is deliberately avoided. It is found that the enthalpy and total potential energy are equal for columns over ocean, but in general, there is an orographic term which cannot be eliminated by redefining the zero-level of geopotential. There is also a term consequent of the departure from hydrostatic balance in the neighborhood of surface irregularities; this term is presumably negligible for columns of cyclone-scale lateral extent. DOI: 10.1111/j.2153-3490.1968.tb00407.x