Microphysics of Titan’s Dynamic Hazes

The organic haze particles in Titan’s atmosphere are one of the most observed features yet still not fully understood. Haze particles likely form from photochemistry near 1000 km, but the main visible portion is centered much lower, around 250 km. Voyager showed a dramatic difference between the appearance of the north and south hemispheres in the main haze layer as well as a detached layer 100 km higher. Cassini revealed that this detached layer changes 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 Titan’s 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 Titan’s 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 Titan’s haze particles and their effects on the observable features in the haze layers.

This research is supported by NASA SSW NNX16AQ09G.