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Astrophysics and Astronomy

Selected Works

Alan Z Liu

Articles 1 - 2 of 2

Full-Text Articles in Physical Sciences and Mathematics

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 Aug 2014

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 …

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Maintenance Of Circulation Anomalies During The 1988 Drought And 1993 Floods Over The United States, Alan Z. Liu, Mingfang Ting, Hailan Wang Oct 2013

Maintenance Of Circulation Anomalies During The 1988 Drought And 1993 Floods Over The United States, Alan Z. Liu, Mingfang Ting, Hailan Wang

Alan Z Liu

The large-scale circulation anomalies associated with the 1988 drought and the 1993 floods are investigated with the National Centers for Environmental Prediction Reanalysis data and a linear stationary wave model. The transient vorticity and thermal forcings are explicitly calculated and the diabatic heating is derived as a residual in the thermodynamic energy equation. Using the April–June (AMJ) data for 1988, and June–August (JJA) data for 1993, the linear stationary wave model is able to reproduce the main features of the geopotential height anomaly for the two seasons when all forcings are included. This provides a basis for further investigation of …

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