Can inducing the Crow instability reduce contrail radiative forcing?

Cação Ferreira, Tânia Sofia [Stanford University] (Co-premier auteur) Caprace, Denis-Gabriel [UCL] (Co-premier auteur) Paoli, Roberto [Ecole Polytechnique de Montreal] Shariff, Karim [NASA Ames Research Center] Lele, Sanjiva Keshava [Stanford University]

We perform time-developing simulations of an aircraft plume in a stratified atmosphere to assess whether artificially inducing the Crow instability of trailing vortices via out-of-phase deflection of two ailerons on each wing (so as to maintain a constant lift) can reduce contrail radiative forcing. The initial condition consists of (a) a vortex sheet with a longitudinally varying strength to mimic the effect of aileron deflection, (b) warm vapor-laden jets that are initially perturbed and (iii) Lagrangian particles in the jets that subsequently grow due to ice deposition. Separate simulations are performed with the compressible charLES code and the incompressible Vortex Particle-Mesh (VPM) method. Radiative forcing is assessed using a parameterization in terms of optical depth. We find that, for a range of surface albedos and zenith angles of the sun, particle redistribution by the forced Crow instability leads to an increased radiative forcing compared to a control case where the instability develops naturally.