Bibliography

Contribution of the lower atmosphere to the day-to-day variation of thermospheric density

In this paper we carried out a numerical experiment using the Specified Dynamics mode of the Whole Atmosphere Community Climate Model with thermosphere and ionosphere eXtension (SD-WACCM-X). One SD-WACCM-X run was with realistic Kp and F10.7 and the other with constant Kp and F10.7. By comparing the day-to-day variability of thermosphere mass density at 300 km (low earth orbit, LEO) and 120 km (reentry level) in these two runs, we find that the density variation at 300 km is mainly driven by geomagnetic and solar forcing while at 120 km it is exclusively controlled by the lower atmosphere. At LEO altitudes, during solar minimum and geomagnetic quiet days, the impact from the lower atmosphere is much smaller than the effect of solar and geomagnetic variations but is not negligible (5–10\% vs 20\%).

Yue, Jia; Yu, Wandi; Pedatella, Nick; Bruinsma, Sean; Wang, Ningchao; Liu, Huixin;

Published by: Advances in Space Research      Published on: jun

YEAR: 2022     DOI: 10.1016/j.asr.2022.06.011

thermosphere; Lower atmosphere; Modeling; Satelllite drag

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

Thermospheric composition O/N response to an altered meridional mean circulation during sudden stratospheric warmings observed by GOLD

Oberheide, J; Pedatella, NM; Gan, Q; Kumari, K; Burns, AG; Eastes, RW;

Published by: Geophysical Research Letters      Published on:

YEAR: 2020     DOI:

Development and Validation of the Whole Atmosphere Community Climate Model With Thermosphere and Ionosphere Extension (WACCM-X 2.0)

Key developments have been made to the NCAR Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension (WACCM-X). Among them, the most important are the self-consistent solution of global electrodynamics, and transport of O⁺ in the F-region. Other ionosphere developments include time-dependent solution of electron/ion temperatures, metastable O⁺ chemistry, and high-cadence solar EUV capability. Additional developments of the thermospheric components are improvements to the momentum and energy equation solvers to account for variable mean molecular mass and specific heat, a new divergence damping scheme, and cooling by O(³P) fine structure. Simulations using this new version of WACCM-X (2.0) have been carried out for solar maximum and minimum conditions. Thermospheric composition, density, and temperatures are in general agreement with measurements and empirical models, including the equatorial mass density anomaly and the midnight density maximum. The amplitudes and seasonal variations of atmospheric tides in the mesosphere and lower thermosphere are in good agreement with observations. Although global mean thermospheric densities are comparable with observations of the annual variation, they lack a clear semiannual variation. In the ionosphere, the low-latitude E \texttimes B drifts agree well with observations in their magnitudes, local time dependence, seasonal, and solar activity variations. The prereversal enhancement in the equatorial region, which is associated with ionospheric irregularities, displays patterns of longitudinal and seasonal variation that are similar to observations. Ionospheric density from the model simulations reproduces the equatorial ionosphere anomaly structures and is in general agreement with observations. The model simulations also capture important ionospheric features during storms.

Liu, Han-Li; Bardeen, Charles; Foster, Benjamin; Lauritzen, Peter; Liu, Jing; Lu, Gang; Marsh, Daniel; Maute, Astrid; McInerney, Joseph; Pedatella, Nicholas; Qian, Liying; Richmond, Arthur; Roble, Raymond; Solomon, Stanley; Vitt, Francis; Wang, Wenbin;

Published by: Journal of Advances in Modeling Earth Systems      Published on: 01/2018

YEAR: 2018     DOI: 10.1002/jame.v10.210.1002/2017MS001232

Whole Atmosphere Community Climate Model—eXtended Version 2.0 Scientific Description

Key developments have been made to the NCAR Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension (WACCM-X). Among them the most

Liu, Han-Li; Bardeen, Charles; Foster, Benjamin; Lauritzen, Peter; Liu, Jing; Lu, Gang; Marsh, Daniel; Maute, Astrid; McInerney, Joseph; Pedatella, Nicholas; , others;

Published by:       Published on:

YEAR: 2018     DOI:

North—south asymmetries in earth’s magnetic field

The solar-wind magnetosphere interaction primarily occurs at altitudes where the dipole component of Earth’s magnetic field is dominating. The disturbances that are created in this interaction propagate along magnetic field lines and interact with the ionosphere–thermosphere system. At ionospheric altitudes, the Earth’s field deviates significantly from a dipole. North–South asymmetries in the magnetic field imply that the magnetosphere–ionosphere–thermosphere (M–I–T) coupling is different in the two hemispheres. In this paper we review the primary differences in the magnetic field at polar latitudes, and the consequences that these have for the M–I–T coupling. We focus on two interhemispheric differences which are thought to have the strongest effects: 1) A difference in the offset between magnetic and geographic poles in the Northern and Southern Hemispheres, and 2) differences in the magnetic field strength at magnetically conjugate regions. These asymmetries lead to differences in plasma convection, neutral winds, total electron content, ion outflow, ionospheric currents and auroral precipitation.

Laundal, Karl; Cnossen, Ingrid; Milan, Stephen; Haaland, SE; Coxon, John; Pedatella, NM; Förster, Matthias; Reistad, Jone;

Published by: Space Science Reviews      Published on:

YEAR: 2017     DOI: 10.1007/s11214-016-0273-0

Ionosphere response to recurrent geomagnetic activity: Local time dependency

Pedatella, N.; Lei, J.; Thayer, J.; Forbes, J.;

Published by: Journal of Geophysical Research      Published on: Jan-01-2010

YEAR: 2010     DOI: 10.1029/2009JA014712

Observations of the ionospheric response to the 15 December 2006 geomagnetic storm: Long-duration positive storm effect

The long-duration positive ionospheric storm effect that occurred on 15 December 2006 is investigated using a combination of ground-based Global Positioning System (GPS) total electron content (TEC), TOPEX and Jason-1 TEC, and topside ionosphere/plasmasphere TEC, GPS radio occultation, and tiny ionospheric photometer (TIP) observations from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites. This multi-instrument approach provides a unique view of the ionospheric positive storm effect by revealing the storm time response in different altitude regions. The ground-based GPS TEC, TOPEX/Jason-1 TEC, and topside ionosphere/plasmasphere TEC all reveal significant enhancements at low latitudes to midlatitudes over the Pacific Ocean region during the initial portions of the storm main phase from 0000–0400 universal time (UT) on 15 December. At low latitudes, the topside ionosphere/plasmasphere TEC increase represents greater than 50\% of the TEC enhancement that is observed by ground-based GPS receivers. Moreover, electron density profiles obtained using the technique of GPS radio occultation demonstrate that the F layer peak height increased by greater than 100 km during this time period. The effects of soft particle precipitation are also apparent in the COSMIC observations of topside ionosphere/plasmasphere TEC. The positive storm effects over the Pacific Ocean region remain present in the equatorial ionization anomaly crest regions beyond 1200 UT on 15 December. This long-lasting positive storm effect is most apparent in ground-based GPS TEC and COSMIC TIP observations, while only a small increase in the topside ionosphere/plasmasphere TEC after 0400 UT is observed. This indicates that the long-lasting positive storm effect occurs predominantly at F region altitudes and, furthermore, that refilling of the topside ionosphere and plasmasphere is not the primary mechanism for producing the long-lasting positive storm phase during this event. The observations suggest that the enhanced eastward electric field and equatorward neutral wind are likely to play a significant role in the generation of long-lasting positive storm effects.

Pedatella, N.; Lei, J.; Larson, K.; Forbes, J.;

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

YEAR: 2009     DOI: https://doi.org/10.1029/2009JA014568

Ionosphere; geomagnetic storm