Stability Analysis of Deep Cloud Streets

Abstract

Linear stability analysis of cloud streets is investigated by including the latent heat and considering a few types of wind profiles. The release of latent heat follows the wave-CISK hypothesis. The results indicate that as the buoyance force released by latent heat becomes dominant, the most unstable mode is stationary relative to the mean wind, and the orientation of cloud streets is parallel to the direction of the wind shear. On the other hand, if the conversion of kinetic energy becomes important, the cloud streets which are perpendicular to the wind shear and propagating relative to the mean wind become most unstable. Results also show that the wavelength, growth rate and orientation angle of the most unstable mode are very sensitive to the height of cloud tops, the strength of wind shear, static stability and the environmental moisture profile. These results compare well with other theoretical results and observations.