Funneling of Meteoric Material into the Polar Winter Vortex

Abstract

Every day of the order of 100 tonnes of meteoric material enters the atmosphere and ablates at 80-100 km. This material is expected to recondense into nanometer-sized meteoric "smoke" particles, and sediment to the lower atmosphere. The meteoric smoke particles are likely to be the dominant aerosol in the upper stratosphere where the temperatures are high enough for the droplets of sulfuric acid solution to evaporate. Meteoric material has been suggested to be of importance for stratospheric nucleation, heterogeneous chemistry and positive ion chemistry. Studies concerning these processes have so far been based on one-dimensional (1D) models of meteoric material, which cannot properly handle atmospheric transport. The first 2D model, which includes both the coagulation and transport of meteoric material, shows that this material is effectively transported to the winter stratosphere. The majority of the global influx of material is thus funneled into the winter vortex. The number and size distribution of meteoric smoke are therefore, unlike what is implicitly assumed with the use of 1D models, highly dependent on latitude and season. We here present the new estimates of number densities and particle area in the stratosphere , and discuss possible consequences for stratospheric processes.