Bibliography

Lower Thermospheric Material Transport via Lagrangian Coherent Structures

We show that inter-model variation due to under-constraint by observations impacts the ability to predict material transport in the lower thermosphere. Lagrangian coherent structures (LCSs), indicating regions of maximal separation (or convergence) in a time-varying flow, are derived in the lower thermosphere from models for several space shuttle water vapor plume events. We find that inter-model differences in thermospheric transport manifest in LCSs in a way that is more stringent than mean wind analyses. LCSs defined using horizontal flow fields from the Specified Dynamics version of the Whole Atmosphere Community Climate Model with thermosphere-ionosphere eXtension (SD-WACCMX) at 109 km altitude are compared to Global Ultraviolet Imager (GUVI) observations of the space shuttle main engine plume. In one case, SD-WACCMX predicts an LCS ridge to produce spreading not found in the observations. LCSs and tracer transport from SD-WACCMX and from data assimilative WACCMX (WACCMX + DART) are compared to each other and to GUVI observations. Differences in the modeled LCSs and tracer positions appear between SD-WACCMX and WACCMX + DART despite the similarity of mean winds. WACCMX + DART produces better tracer transport results for a July 2006 event, but it is unclear which model performs better in terms of LCS ridges. For a February 2010 event, when mean winds differ by up to 50 m/s between the models, differences in LCSs and tracer trajectories are even more severe. Low-pass filtering the winds up to zonal wavenumber 6 reduces but does not eliminate inter-model LCS differences. Inter-model alignment of LCSs improves at a lower 60 km altitude.

Datta-Barua, Seebany; Pedatella, Nicholas; Greer, Katelynn; Wang, Ningchao; Nutter, Leanne; Harvey, Lynn;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2020JA028834

Deducing Non-Migrating Diurnal Tides in the Middle Thermosphere With GOLD Observations of the Earth's far Ultraviolet Dayglow From Geostationary Orbit

The global-scale observations of the limb and disk (GOLD) Mission images middle thermosphere temperature and the vertical column density ratio of oxygen to molecular nitrogen (O/N2) using its far ultraviolet imaging spectrographs in geostationary orbit. Since GOLD only measures these quantities during daylight, and only over the ∼140° of longitude visible from geostationary orbit, previously developed tidal analysis techniques cannot be applied to the GOLD data set. This paper presents a novel approach that deduces two specified non-migrating diurnal tides using simultaneous measurements of temperature and O/N2. DE3 (diurnal eastward propagating wave 3) and DE2 (diurnal eastward propagating wave 2) during October 2018 and January 2020 are the focus of this paper. Sensitivity analyses using TIE-GCM simulations reveal that our approach reliably retrieves the true phases, whereas a combination of residual contributions from secondary tides, the restriction in longitude, and random uncertainty can lead to ∼50\% error in the retrieved amplitudes. Application of our approach to GOLD data during these time periods provides the first observations of non-migrating diurnal tides in measurements taken from geostationary orbit. We identify discrepancies between GOLD observations and TIE-GCM modeling. Retrieved tidal amplitudes from GOLD observations exceed their respective TIE-GCM amplitudes by a factor of two in some cases.

Krier, Christopher; England, Scott; Greer, Katelynn; Evans, Scott; Burns, Alan; Eastes, Richard;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2021JA029563

airglow; composition; temperature; thermosphere; tides

Impact of September 2019 Antarctic Sudden Stratospheric Warming on Mid-Latitude Ionosphere and Thermosphere Over North America and Europe

Goncharenko, Larisa; Harvey, Lynn; Greer, Katelynn; Zhang, Shun-Rong; Coster, Anthea; Paxton, Larry;

Published by: Geophysical Research Letters      Published on:

YEAR: 2021     DOI:

First Comparison of Traveling Atmospheric Disturbances Observed in the Middle Thermosphere by Global-Scale Observations of the Limb and Disk to Traveling Ionospheric Disturbances Seen in Ground-Based Total Electron Content Observations

Traveling ionospheric disturbances (TIDs) and their neutral counterparts known as traveling atmospheric disturbances (TADs) are believed to play a role in communicating inputs to other locations in the fluid. While these two phenomena are believed to be connected, they may not have a one-to-one correspondence as the geomagnetic field influences the TID but has no direct impact on the TAD. The relative amplitudes of the perturbations seen in the ionosphere and atmosphere have been observed but rarely together. This study reports results from a 3-day campaign to observe TIDs and TADs simultaneously over a broad latitudinal region over the eastern United States using a combination of Global-scale Observations of the Limb and Disk (GOLD) and a distributed network of ground-based Global Navigation Satellite System (GNSS) receivers. These results demonstrate that GOLD and the ground-based total electron content (TEC) observations can see the atmospheric and ionospheric portions of a large-scale traveling disturbance. The phase difference in the perturbations to the GOLD airglow brightness, O/N2 and thermospheric disk temperature are consistent with an atmospheric gravity wave moving through this region. The ionospheric signatures move at the same rate as those in the atmosphere, but their amplitudes do not have a simple correspondence to the amplitude of the signal seen in the atmosphere. This campaign demonstrates a proof-of-concept that this combination of observations is able to provide information on TIDs and TADs, including quantifying their impact on the temperature and chemical composition of the upper atmosphere.

England, Scott; Greer, Katelynn; Zhang, Shun-Rong; Evans, Scott; Solomon, Stanley; Eastes, Richard; McClintock, William; Burns, Alan;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2021JA029248

Ionosphere; thermosphere; airglow; atmospheric waves

Longitudinally Varying Thermospheric Composition and Its Connection to the Extraordinary 2019 SSW

Greer, Katelynn; Harvey, Lynn; Goncharenko, Larisa;

Published by:       Published on:

YEAR: 2020     DOI:

Drivers and Prediction of Variability in Earth’s Ionosphere and Thermosphere: New Observations from Missions I

Immel, Thomas; Greer, Katelynn; Lieberman, Ruth; Paxton, Larry;

Published by:       Published on:

YEAR: 2020     DOI:

Drivers and Prediction of Variability in Earth’s Ionosphere and Thermosphere: New Observations from Missions II Posters

Immel, Thomas; Greer, Katelynn; Lieberman, Ruth; Paxton, Larry;

Published by:       Published on:

YEAR: 2020     DOI:

Variations of lower thermospheric FUV emissions based on GOLD observations and GLOW modeling

Greer, KR; Eastes, Richard; Solomon, Stan; McClintock, William; Burns, Alan; Rusch, David;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2020     DOI:

ICON at AGU Fall Meeting

Greer, Katelynn; Triplett, Colin; , others;

Published by:       Published on:

YEAR: 2019     DOI:

Modeled gravity wave-like perturbations in the brightness of far ultraviolet emissions for the GOLD mission

The NASA Global‐scale Observations of Limb and Disk (GOLD) mission will study the coupling of the thermosphere with the lower atmosphere through an examination of temperature

Greer, KR; England, SL; Becker, E; Rusch, D; Eastes, R;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2018     DOI: 10.1029/2018JA025501

Wave Driven Disturbances of the Thermal Structure in the Polar Winter Upper Stratosphere and Lower Mesosphere

The polar winter middle atmosphere is a dynamically active region that is driven primarily by wave activity. Planetary waves intermittently disturbed the region at different levels and the

Greer, Katelynn;

Published by:       Published on:

YEAR: 2013     DOI: