Convective Instability Underneath Midlevel Clouds: Comparisons between Numerical Simulations and VHF Radar Observations

Fragmentation Instability of Molecular Clouds: Numerical Simulations

We simulate fragmentation and gravitational collapse of cold, magnetized molecular clouds. We explore the nonlinear development of an instability mediated by ambipolar diffusion, in which the collapse rate is intermediate to fast gravitational collapse and slow quasistatic collapse. Initially uniform stable clouds fragment into elongated clumps with masses largely determined by the cloud temper...

VHF radar, radiosondes and numerical modelling

Introduction Conclusions References

VHF/UHF radar observations of tropical mesoscale convective systems over southern India

Several campaigns have been carried out to study the convective systems over Gadanki (13.5 N, 79.2 E), a tropical station in India, using VHF and UHF radars. The height-time sections of several convective systems are investigated in detail to study reflectivity, turbulence and vertical velocity structure. Structure and dynamics of the convective systems are the main objectives of these campaign...

Comparisons between EUV/IMAGE observations and numerical simulations of the plasmapause formation

Simulations of plasmapause formation described in Pierrard and Lemaire (2004) predict the shape and equatorial distance of the plasmapause as a function of the geomagnetic activity index Kp. The equatorial positions predicted by this model are compared with the observations of EUV/IMAGE during the geomagnetic storm of 24 May 2000, substorm events of 10 June 2001 and 25 June 2000, and also durin...

Idealized simulations of pyro-convective clouds