A selection of highlights culled from publications by HAO staff.
Thermospheric Density Perturbations Produced by Traveling Atmospheric Disturbances during August 2005 Storm
K. H. Pham, W. Wang, H. Liu, D. Lin, M. Wiltberger, et al. discuss how during geomagnetic storms, increased activity within the geospace environment causes large scale plasma convection to occur and electrons to precipitate into the upper atmosphere. The enhanced heating of the thermosphere by the plasma convection and electron precipitation can produce large perturbations in the neutral density.
N.M. Pedatella and J.L. Anderson present study investigates the impact of assimilating electron density profiles from the Constellation Observing System for Meteorology, Ionosphere, and Climate-2 (COSMIC-2) mission in a whole atmosphere data assimilation system. The observations are assimilated into the Whole Atmosphere Community Climate Model with thermosphere-ionosphere eXtension (WACCMX) using the Data Assimilation Research Testbed (DART) ensemble adjustment Kalman filter.
Hemispherically Asymmetric Evolution of Nighttime Ionospheric Equatorial Ionization Anomaly in the American Longitude Sector
Xuguang Cai, Liying Qian, Wenbin Wang, Joseph M. McInerney, Han-Li Liu, Richard W. Eastes in JGR–Space Physics reveal that the Global-scale Observation of Limb and Disk (GOLD) mission observed distinct post-sunset, hemispherically asymmetric evolution of the equatorial ionization anomaly between 40° and 50°W on 19 November 2018, with the southern crest shifting poleward but the northern crest remaining in the same latitude region. The Whole Atmosphere Community Climate Model-eXtended captured this phenomenon.
Nicholas Pedatella investigates the variability in the ionosphere during the 2020-2021 sudden stratospheric warming (SSW) using a combination of Constellation Observing System for Meteorology, Ionosphere, and Climate-2 (COSMIC-2) observations and Whole Atmosphere Community Climate Model with thermosphere-ionosphere eXtension (WACCM-X) simulations. The unprecedented spatial-temporal sampling of the low latitude ionosphere afforded by COSMIC-2 enables investigating the short-term ($<$ 5 days) variability in the ionosphere during the SSW event
An improved MHD simulation of the 2006 December 13 coronal mass ejection of active region NOAA 10930
Yuhong Fan presents an magnetohydrodynamic (MHD) simulation of the coronal mass ejection (CME) on 13 December 2006 in the emerging $\delta$-sunspot active region 10930, improving upon a previous simulation by Fan (2016). It is found that the kinematics of the erupting flux rope is significantly affected by the open magnetic fields and fast solar wind streams adjacent to the active region.
Thermospheric Neutral Density Variation during the "SpaceX" Storm: Implications from Physics-based Whole Geospace Modeling
In this study, Dong Lin, Wenbin Wang, Katherine Garcia-Sage, Jia Yue, Viacheslav Merkin, Joseph McInerney, Kevin Pham, and Kareem Sorathi compare the performance of a state-of-the-art physics-based, fully coupled whole geospace model and empirical models in predicting the neutral mass density variation in the thermosphere. It turns out that the physics-based model is more accurate in capturing the magnitude of storm enhancement of neutral density.
Synthetic Lyman-α Emissions for the coronagraph aboard the ASO-S mission I: an Eruptive Prominence-cavity System
J. Zhao, P. Zhang, S. E. Gibson, Y. Fan, L. Feng, F. Yu, H. Li, and W. Q. Gan present a discussion of the evolution of the eruptive prominence-cavity system as observed by the Lyman-α Solar Telescope (LST), analyzing the synthetic emissions both on the disk near the limb and in the corona as viewed by the coronagraph, as well as the three-dimensional data of MHD simulations.
A. Ruminska, U. Bak-Steslicka, S. E. Gibson, and Y. Fan studied quiescent coronal cavities observed between 2012 and 2018 by the Coronal Multichannel Polarimeter (CoMP). The majority of cavities in their study had a characteristic lagomorphic structure in linear polarization. They additionally compared cavity widths as observed in intensity with sizes of their linear polarization signatures for 70 cavities and found that both features are strongly correlated.
M. Dikpati, P. A. Gilman, G. A. Guerrero, A. G. Kosovichev, S. W. McIntosh, K. R. Sreenivasan, J. Warnecke, T. V. Zaqarashvili show that Rossby waves in the supergranule layer can be excited by an inverse cascade of kinetic energy from the nearly horizontal motions in supergranules. They illustrate how this excitation occurs using a hydrodynamic shallow-water model for a 3D thin rotating spherical shell.