AS4.2Impacts of cosmic dust in the terrestrial and other planetary atmospheres (including Vilhelm Bjerknes Medal Lecture)
|Convener: John Plane | Co-Conveners: Zoltan Sternovsky , Jorge Luis Chau|
The amount of cosmic dust which enters the Earth’s atmosphere is highly uncertain, with recent estimates varying by up to 2 orders of magnitude. The first aim of this session will be to explore the different techniques that are used to measure the cosmic dust influx, such as space-borne dust detectors, meteor radars, lidar measurements of metal atoms in the upper mesosphere, optical extinction of meteoric smoke particles in the mesosphere and stratosphere, refractory cores in stratospheric sulphate particles, and the deposition of cosmic spherules and meteoric smoke in ice cores.
The second aim will be to examine the impacts of meteoric ablation in the atmosphere, which include: sporadic E layers in the lower thermosphere; layers of metal atoms, airglow emissions, and noctilucent clouds in the upper mesosphere; the removal of acids and reactive radicals in the mesosphere and stratosphere; and the nucleation and freezing properties of polar stratospheric clouds in the lower stratosphere.
Observations of the impact of cosmic dust in the atmospheres of other solar system bodies provide important contrasts with the Earth, and also help to constrain astronomical models of the evolution of dust produced by comets and asteroids. Comet Siding Spring made a close fly-by of Mars in October 2014, providing a unique opportunity for the MAVEN spacecraft to observe the “dusting” of a planetary atmosphere. Cosmic dust impacts have also been observed in the atmospheres of Venus and Titan.
Papers will be solicited which deal with all aspects of the atmospheric impacts of cosmic dust, including observations, relevant laboratory studies and modelling.