Convective clouds generate internal gravity waves during their development, maturity and dissipation. Such waves can have horizontal scales ranging from hundreds of meters upwards, and periods ranging from minutes to hours. In addition to being important contributors to the momentum budget of the atmosphere, gravity waves generated by convective clouds have local effects also. It is thought that one such effect is the generation of turbulence in the vicinity of deep convection. Such turbulence has important consequences for the aviation community. It is the role of gravity waves in generating "near cloud" turbulence which is the focus of this seminar.

Preliminary results from a cloud resolving model will be presented which document the development of an idealized convective cloud. The model configuration and initialization is motivated by an observed near cloud turbulence encounter. The modeled cloud generates gravity waves which are initially confined to the region directly above the convective updrafts and after dispersing are seen to break in the region above and around the cloud. Subsequently, the model produces turbulence in the clear air at heights ranging from the cloud top upwards; approximately corresponding to the flight level of commercial aircraft. The mechanism causing the breaking will be discussed, as well as the importance of wave breaking in generating near cloud turbulence.

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