Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 5 of 5
Full-Text Articles in Physical Sciences and Mathematics
Interferometric Imaging With Eiscat_3d For Fine-Scale In-Beam Incoherent Scatter Spectra Measurements, M. Zettergren, Devin Huyghebaert, Björn Gustavsson, Juha Vierinen, Andreas Kvammen, John Swoboda, Ilkka Virtanen, Spencer Hatch, Karl M. Laundal
Interferometric Imaging With Eiscat_3d For Fine-Scale In-Beam Incoherent Scatter Spectra Measurements, M. Zettergren, Devin Huyghebaert, Björn Gustavsson, Juha Vierinen, Andreas Kvammen, John Swoboda, Ilkka Virtanen, Spencer Hatch, Karl M. Laundal
Publications
The 233 MHz EISCAT_3D radar system currently under construction in northern Fennoscandia will be able to resolve ionospheric structures smaller than the transmit beam dimensions through the use of interferometric imaging. This capability is made possible by the modular design and digitization of the 119 91-antenna panels located at the main Skibotn site. The main array consists of a cluster of 109 panels, with 10 outlier panels producing unique interferometry baselines. In the present study synthesized incoherent scatter radar signal measurements are used for interferometric imaging analysis with the EISCAT_3D system. The Geospace Environment Model of Ion-Neutral Interactions (GEMINI) model …
Accelerating Atmospheric Gravity Wave Simulations Using Machine Learning: Kelvin-Helmholtz Instability And Mountain Wave Sources Driving Gravity Wave Breaking And Secondary Gravity Wave Generation, Wenjun Dong, David Fritts, Alan Z. Liu, Hanli Liu, Jonathan Snively
Accelerating Atmospheric Gravity Wave Simulations Using Machine Learning: Kelvin-Helmholtz Instability And Mountain Wave Sources Driving Gravity Wave Breaking And Secondary Gravity Wave Generation, Wenjun Dong, David Fritts, Alan Z. Liu, Hanli Liu, Jonathan Snively
Publications
Gravity waves (GWs) and their associated multi-scale dynamics are known to play fundamental roles in energy and momentum transport and deposition processes throughout the atmosphere. We describe an initial, two-dimensional (2-D), machine learning model – the Compressible Atmosphere Model Network (CAMNet) - intended as a first step toward a more general, three-dimensional, highly-efficient, model for applications to nonlinear GW dynamics description. CAMNet employs a physics-informed neural operator to dramatically accelerate GW and secondary GW (SGW) simulations applied to two GW sources to date. CAMNet is trained on high-resolution simulations by the state-of-the-art model Complex Geometry Compressible Atmosphere Model (CGCAM). Two …
Oxygen Ion Escape At Venus Associated With Three-Dimensional Kelvin-Helmholtz Instability, Tong Dang, Xuanye Ma, Jiuhou Le, Binzheng Zhang, Tielong Zhang, Zhonghua Yao, John Lyon, Sudong Xiao, Maodong Yan, Oliver Brambles, Kareem Sorathia
Oxygen Ion Escape At Venus Associated With Three-Dimensional Kelvin-Helmholtz Instability, Tong Dang, Xuanye Ma, Jiuhou Le, Binzheng Zhang, Tielong Zhang, Zhonghua Yao, John Lyon, Sudong Xiao, Maodong Yan, Oliver Brambles, Kareem Sorathia
Publications
How oxygens escape from Venus has long been a fundamental but controversial topic in the planetary research. Among various key mechanisms, the Kelvin-Helmholtz instability (KHI) has been suggested to play an important role in the oxygen ion escape from Venus. Limited by either scarce in-situ observations or simplified theoretical estimations, the mystery of oxygen ion escape process associated with KHI is still unsettled. Here we present the first three-dimensional configuration of KHI at Venus with a global multifluid magnetohydrodynamics model, showing a significantly fine structure and evolution of the KHI. KHI mainly occurred at the low latitude boundary layer if …
The Source Of Auroral Omegas, Heidi K. Nykyri, J.M. Weygand, Mostafa El-Alaoui
The Source Of Auroral Omegas, Heidi K. Nykyri, J.M. Weygand, Mostafa El-Alaoui
Publications
The auroral wave-like structures called “omega bands” appear within the post-midnight sector auroral oval with shapes resembling the Greek letter omega, and are typically associated with the recovery phase of substorms. Prior work and MHD simulations suggest both high speed earthward flows and postmidnight flow shears are possible omega band source mechanisms. However, what produces omega bands is not well understood. It is most likely that the paucity of concurrent magnetospheric data has limited our ability to understand fully the mechanism responsible for the generation of the omega bands. We have identified about 263 auroral omegas in seven different THEMIS …
Kelvin-Helmholtz Billow Interactions And Instabilities In The Mesosphere Over The Andes Lidar Observatory: 1. Observations, J. H. Hecht, R. L. Walterscheid, A. Z. Liu, D. C. Fritts, L. J. Gelinas, R. J. Rudy
Kelvin-Helmholtz Billow Interactions And Instabilities In The Mesosphere Over The Andes Lidar Observatory: 1. Observations, J. H. Hecht, R. L. Walterscheid, A. Z. Liu, D. C. Fritts, L. J. Gelinas, R. J. Rudy
Publications
A very high spatial resolution (∼25 m pixel at 90 km altitude) OH airglow imager was installed at the Andes Lidar Observatory on Cerro Pachón, Chile, in February 2016. This instrument was collocated with a Na wind-temperature lidar. On 1 March 2016, the lidar data showed that the atmosphere was dynamically unstable before 0100 UT and thus conducive to the formation of Kelvin-Helmholtz instabilities (KHIs). The imager revealed the presence of a KHI and an apparent atmospheric gravity wave (AGW) propagating approximately perpendicular to the plane of primary KHI motions. The AGW appears to have induced modulations of the shear …