We analyze spectral scans of narrow-band images across the Na D2 line. They were obtained from disc centre of the Sun with our Fabry-Perot interferometer (FPI) in the Vacuum Tower Telescope at the Observatorio del Teide. The FPI was set to a bandwidth of 200 mÅ FWHM and the spectral stepwidth was 100 mÅ. Our aim is to study the variation of the granulation pattern with height in the atmosphere....

The conventional definition of rogue waves in the ocean is that their heights, from crest to trough, are more than about twice the significant wave height, which is the average wave height of the largest one-third of nearby waves. When modeling deep water waves using the nonlinear Schrödinger equation, the most likely candidate satisfying this criterion is the so-called Peregrine solution. It i...

Mountain waves could be modified as the boundary layer varies between stable and convective. However case studies show mountain waves day and night, and above e.g. convective rolls with precipitation lines over mountains. VHF radar measurements of vertical wind (1990–2006) confirm a seasonal variation of mountain-wave amplitude, yet there is little diurnal variation of amplitude. Mountain-wave ...

Observations from the island of Montserrat in the Caribbean have shown that volcanic eruptions (particularly explosive ones) can generate internal waves in the atmosphere that can be observed by microbarographs at ground level. It is possible that observations of such waves may give early information about volcanic eruptions when other methods are unavailable (because of bad weather, nocturnal ...

We investigate wave solutions of a lubrication model for surfactant-driven flow of a thin liquid film down an inclined plane. We model the flow in one space dimension with a system of nonlinear PDEs of mixed hyperbolic-parabolic type in which the effects of capillarity and surface diffusion are neglected. Numerical solutions reveal distinct patterns of waves that are described analytically by c...

It has only been in the last few years that accurate measurement of the horizontal pressure gradient has been possible over complex terrain using an airborne platform. To infer forcing mechanisms for the wind, an independent measure of the height of an isobaric surface is required. Differential GPS analyses have enabled determination of the aircraft height with sufficient accuracy to infer isob...

OBJECTIVES This study sought to present evidence that short stature is a hemodynamic liability, which could explain in part the inverse relation between body height and cardiovascular risk. BACKGROUND Other explanations for the association of short stature with increased cardiovascular risk include advancing age, reduced pulmonary function, genetic factors, poor childhood nutrition and small-...

The propagation of shear waves in an anisotropic fluid saturated porous layer over a prestressed semi-infinite homogeneous elastic half-space lying under an elastic homogeneous layer with irregularity present at the interface with rigid boundary has been studied. The rectangular irregularity has been taken in the half-space. The dispersion equation for shear waves is derived by using the pertur...

Context. The continuum intensity at wavelengths around 1 mm provides an excellent way to probe the solar chromosphere and thus valuable input for the ongoing controversy on the thermal structure and the dynamics of this layer. Aims. The synthetic continuum intensity maps for near-millimetre wavelengths presented here demonstrate the potential of future observations of the small-scale structure ...