Ozone depletion above Kiruna (67.9N, 21.1E), Sweden, was investigated using daily ozone and temperature measurements by ozonesondes between 1 February and 25 March 1997. Using UKMO Ertel’s potential vorticity (EPV) and wind fields, three dynamically distinct regions were defined on a grid of isentropic surfaces viz.: the polar vortex boundary region characterized by steep EPV gradients, the are...

A major question for climate studies is to quantify the role of turbulent eddy fluxes in maintaining the observed atmospheric mean state. Both the equator-to-pole temperature gradient and the static stability of the extratropical atmosphere are set by a balance between these eddy fluxes and the radiative forcing. Much attention has been paid to the adjustment of the isentropic slope, which rela...

For the purpose of engineering, it is important to study convergent rates in process low Mach number limit. However, there are only a few results on this issue, which focus cases isentropic regime or ones without solid boundaries. In paper, we obtain convergence for local strong solutions non-isentropic compressible Navier-Stokes equations with well-prepared initial data and Navier-slip boundar...

Starting from a standard description of an ideal, isentropic fluid, we derive the effective theory governing a gapless non-relativistic mode—the sound mode. The theory, which is dictated by the requirement of Galilei invariance, entails the entire set of hydrodynamic equations. The gaplessness of the sound mode is explained by identifying it as the Goldstone mode associated with the spontaneous...

SUMMARY The aerodynamic design and experimental performance of a centrifugal compressor designed for a pressure ratio of 6.5 and a specific speed of 68 are described, The compressor consisted of a radially-vaned impeller and a transonic, vaned radial diffuser. At design speed a peak overall total-to-total isentropic efficiency of 0.746 was achieved at the maximum pressure ratio of 5.9, rising t...