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Measuring Eddy Heat And Constituent Fluxes With High-Resolution Na And Fe Doppler Lidars, Chester S. Gardner, Alan Z. Liu
Measuring Eddy Heat And Constituent Fluxes With High-Resolution Na And Fe Doppler Lidars, Chester S. Gardner, Alan Z. Liu
Alan Z Liu
Vertical transport by turbulent mixing plays a fundamental role in establishing the thermal and
constituent structure of the upper mesosphere and lower thermosphere (MLT). Because of observational
challenges, eddy heat, constituent, and momentum fluxes, and the associated coefficients for thermal (kH),
constituent (kzz), and momentum (kM), diffusion have not been well characterized in the MLT. We show that
properly configured Na and Fe Doppler lidars, with sufficient resolution to observe the turbulence-induced wind,
temperature, and density fluctuations, can make direct measurements of eddy …
Inferring The Global Cosmic Dust Influx To The Earth’S Atmosphere From Lidar Observations Of The Vertical Flux Of Mesospheric Na, Chester S. Gardner, Alan Z. Liu, Dan Marsh, Wuhu Feng, John Plane
Inferring The Global Cosmic Dust Influx To The Earth’S Atmosphere From Lidar Observations Of The Vertical Flux Of Mesospheric Na, Chester S. Gardner, Alan Z. Liu, Dan Marsh, Wuhu Feng, John Plane
Alan Z Liu
Estimates of the global influx of cosmic dust are highly uncertain, ranging from 0.4–110 t/d. All
meteoric debris that enters the Earth’s atmosphere is eventually transported to the surface. The downward
fluxes of meteoric metals like mesospheric Na and Fe, in the region below where they are vaporized and
where the majority of these species are still in atomic form, are equal to their meteoric ablation influxes,
which in turn, are proportional to the total cosmic dust influx. Doppler lidar measurements of mesospheric Na
fluxes made throughout the …
Removing Milky Way From Airglow Images Using Principle Component Analysis, Zhenhua Li, Alan Z. Liu, Gulamabas G. Sivjee
Removing Milky Way From Airglow Images Using Principle Component Analysis, Zhenhua Li, Alan Z. Liu, Gulamabas G. Sivjee
Alan Z Liu
Airglow imaging is an effective way to obtain atmospheric gravity wave information in the airglow layers in the upper mesosphere and the lower thermosphere. Airglow images are often contaminated by the Milky Way emission. To extract gravity wave parameters correctly, the Milky Way must be removed. The paper demonstrates that principal component analysis (PCA) can effectively represent the dominant variation patterns of the intensity of airglow images that are associated with the slow moving Milky Way features. Subtracting this PCA reconstructed field reveals gravity waves that are otherwise overwhelmed by the strong spurious waves associated with the Milky Way. Numerical …