Synoptic situations producing rainfall at four rawinsonde observatories at eastern Spain are classified as stratiform or convective depending on dynamic and thermodynamic instability indices. Two daily radiosonde and daily-accumulated precipitation data from four observatories in Eastern Spain are used: Madrid-Barajas (MB), Murcia (MU), Palma de Mallorca (PA) and Zaragoza (ZA). We calculated tw...

[1] Laboratory and numerical experiments show that when a chemically different layer overlies a hotter but otherwise denser layer, analogous to continental mantle lithosphere over asthenosphere, convective stability depends strongly on both the critical Rayleigh number and the buoyancy number, B, of the lithosphere-like layer. Sufficient cooling at low buoyancy number results in an oscillatory ...

The instability modes arising within simple non-reversing pulsatile flows in a circular tube with a smooth axisymmetric constriction are examined using global Floquet stability analysis and direct numerical simulation. The sectionally averaged pulsatile flow is represented with one harmonic component superimposed on a time-mean flow. We have previously identified a period-doubling global instab...

We examine an epitaxial crystal growth model in the context of absolute and convective instabilities and show that a strain-induced step bunching instability can be convective. Using analytic stability theory and numerical simulations, we study the response of the crystal surface to an inhomogeneous deposition flux that launches impulsive and time-periodic perturbations to a uniform array of st...

Noise-induced absolute instability is demonstrated in computer experiments with a one-dimensional reaction– diffusion system. This phenomenon may occur in spatially extended flow systems of different nature, when the parameters are chosen close to the point of transition from convective to absolute instability. © 2002 IMACS. Published by Elsevier Science B.V. All rights reserved.

The characteristics of the most unstable fundamental mode and the first harmonic excited in the convection zone of a variety of solar envelope models are shown to be in reasonable agreement with the observed features of granulation and supergranulation.