In order to understand cloud clusters and a meso-a-scale low, which were observed on the China Continent on 29 June 1998, numerical experiments are performed with a model which intends to resolve mesoscale organized convection, the effects of cumulus convection being incorporated as the subgridscale. The horizontal grid size is taken to be about 5 km for the fine grid area of the triply-nested ...

A nonlinear, compressible, spectral collocation code is employed to examine gravity wave breaking in two and three spatial dimensions. Twodimensional results exhibit a structure consistent with previous efforts and suggest wave instability occurs via convective rolls aligned normal to the gravity wave motion (uniform in the spanwise direction). Three-dimensionM results demonstrate, in contrast,...

Low-mass stars, ∼ 1 − 2 solar masses, near the Main Sequence are efficient at producing He, which they mix into the convective envelope on the giant branch and distribute into the Galaxy by way of envelope loss. This process is so efficient that it is difficult to reconcile the observed cosmic abundance of He with the predictions of Big Bang nucleosynthesis. In this paper we find, by modeling a...

Cross-diffusion phenomena are experimentally shown to be able to induce convective fingering around an initially stable stratification of two microemulsions with different compositions. Upon diffusion of a salt that entrains water and AOT micelles by cross-diffusion, the miscible interface deforms into fingers following the build-up of a non-monotonic density profile in the gravitational field....

[1] Numerical simulations are performed to investigate the interaction of a semidiurnal internal wave (IW) beam with the nonuniform stratification of an upper ocean pycnocline. During the initial stage of the interaction, higher harmonics originate after reflection of the IW beam at the caustic and are trapped in the pycnocline. In cases where the pycnocline thickness is sufficiently large (app...

Mathematical models have been highly successful at reproducing the complex spatiotemporal phenomena seen in many biological systems. However, the ability to numerically simulate such phenomena currently far outstrips detailed mathematical understanding. This paper reviews the theory of absolute and convective instability, which has the potential to redress this inbalance in some cases. In spati...

Convection cannot be explicitly resolved in general circulation models given their typical grid size of 50 km or larger. However, by multiplying the vertical acceleration in the equation of motion by a constant larger than unity, the horizontal scale of convection can be increased at will, without necessarily affecting the larger-scale flow. The resulting hypohydrostatic system has been recogni...

Aims. During the first 40 s after their birth, proto-neutron stars are expected to be subject to at least two types of instability. The first one, the convective instability, is excited in the inner regions, where the entropy gradient produces a Rayleigh-type convection. The second one, the neutron-finger instability, is instead excited in the outer layers where the lepton gradients are large. ...

Saio et al. (2006) have shown that the presence of an intermediate convective zone (ICZ) in post-main sequence models could prevent the propagation of g-modes in the radiative interior and hence avoid the corresponding radiative damping. The development of such a convective region highly depends on the structure of the star in the μ-gradient region surrounding the convective core during the mai...

A ground-based microwave radiometer gives the possibility of providing continuously available temperature and humidity profiles of the troposphere, from which instability indices of the atmosphere could be derived. This paper studies the possibility of correlating the radiometer-based instability indices with the occurrence of intense convective activity, namely, the occurrence of lightning. Th...