Plane, John, Gerding, Michael, Mangan, Thomas, Daly, Shane, Bones, David, Sanchez, Juan Diego Carrillo, and Feng, Wuhu
Ni atoms are produced by the ablation of cosmic dust particles entering the atmosphere.During six nights between January and March 2018, the mesospheric Ni layer was observedby lidar from Kühlungsborn, Germany (54oN, 12oE). Most of the soundings used atransition from the low-lying excited Ni(3D) state at 341 nm (the first time an excitedstate has been used for a lidar). The Ni layer peaks around 85 km, with nightlymean Ni peak densities ranging from 280 - 450 cm−3. The ratio of the Fe to Niabundance is ∼38, which is a factor of 2 larger than the ratio in CI chondrites (and afactor of 32 larger than the Fe/Ni ratio observed by the only previous measurementof mesospheric Ni). In the laboratory, three experimental systems were used tointerpret these observations: a Meteoric Ablation Simulator, to study the ablation of Nirelative to Na and Fe; a Pulsed Laser Photolysis/Fluorescence system to measurethe reaction kinetics of neutral Ni and NiO; and a Fast Flow Tube to measure theion-molecule kinetics of Ni+ and NiO+. A new version of the Chemical Ablation Model –containing an Fe-Ni phase as well as the standard silicate phase – was combinedwith the ZoDy astronomical dust model to predict the injection rate of Ni into themesosphere. This Ni Meteoric Input Function, together with the new reaction ratecoefficients, was then added to the Whole Atmosphere Community Climate Model toperform global simulations of the Ni layer for comparison with the lidar observations. [ABSTRACT FROM AUTHOR]