Exploring the Mechanisms Controlling Titan's Detached Haze Layer with a Coupled GCM/Microphysics Model

Our understanding of the organic haze particles in Titans atmosphere has evolved given the multitude of observations, yet many aspects still remain unresolved. Photochemistry occurring in the upper atmosphere begins the haze formation process, but the main visible portion is centered much lower, around 250 km. Voyager images revealed a dramatic difference in the shading of the main haze layer between the northern and southern hemispheres as well as a detached layer 100 km higher. Cassini images showed that this detached layer moves in altitude over time (from 350 km up to 500 km). Retrievals from both spacecraft and the Huygens probe indicate that the haze particles are fractal aggregates. We have been working to incorporate the aerosol physics of CARMA into the TitanWRF general circulation model in order to understand the roles of microphysics vs. dynamics in the global appearance of the haze layers in Titans atmosphere. CARMA is a 1-D aerosol microphysics and radiative transfer model which includes sedimentation, coagulation, and particle charging physics that influence the haze particles in Titans atmosphere. TitanWRF is a multi-scale, hydrostatic, planetary atmospheric model that can simulate the global transport of haze particles. The combined model allows us to more fully explore latitudinal changes to the size and shape of Titans haze particles, their effects on the observable features in the haze layers, and distinguish the influence of atmospheric dynamics vs. microphysics on the detached haze layer.