Gravity waves and clear air turbulence generated by convective storms in different wind shear environments

Clear air turbulence (CAT) is a major threat to aviation safety and convective storms are a major cause of such turbulence. Recent Air France Flight 447 crash into the Atlantic Ocean and its possible link to storm-generated turbulence should serve as a fresh reminder of this vital threat. While it is known that convective storms can generate strong CAT, our understanding of the relation between CAT and convective storms remains inadequate. This is especially so in the upper troposphere and lower stratosphere (UT/LS) region as direct observations are difficult to perform.

Since convectively generated CAT is associated with the gravity waves, we need to understand how storms generate these waves in different environments, particularly environments with different wind shear structures. It is known that UT/LS wind shear structures are different in middle and low latitudes. This study will examine gravity wave generation and the associated CAT by convective storms developed in different wind shear environments. We will use a 3-D convective cloud resolving model with full sets of microphysics to simulate deep convective storms in different wind shear conditions. The model results will be analyzed to reveal the behavior of gravity waves and CAT caused by the development of these storms. Satellite storm images will be used for comparing with and validating model results. Implications to aviation safety of the findings, especially that contrast midlatitude to tropical convective storms, will be discussed.