Impacts of Thunderstorm-Generated Gravity Waves on the Ionosphere-Thermosphere Using TIEGCM-NG/MAGIC Simulations and Comparisons With GNSS TEC, ICON, and COSMIC-2 Observations.

We use the TIEGCM-NG nudged by MAGIC gravity waves to study the impacts of a severe thunderstorm system, with a hundred tornado touchdowns, on the ionospheric and thermospheric disturbances. The generated waves induce a distinct concentric ring pattern on GNSS TIDs with horizontal scales of 150-400 km and phase speeds of 150-300 m/s, which is well simulated by the model. The waves show substantial vertical evolution in period, initially dominated by 0.

Geospace Concussion: Global Reversal of Ionospheric Vertical Plasma Drift in Response to a Sudden Commencement.

An interplanetary shock can abruptly compress the magnetosphere, excite magnetospheric waves and field-aligned currents, and cause a ground magnetic response known as a sudden commencement (SC). However, the transient (<∼1 min) response of the ionosphere-thermosphere system during an SC has been little studied due to limited temporal resolution in previous investigations. Here, we report observations of a global reversal of ionospheric vertical plasma motion during an SC on 24 October 2011 using ∼6 s resolution Super Dual Auroral Radar Network ground scatter data.

A Test of Energetic Particle Precipitation Models Using Simultaneous Incoherent Scatter Radar and Van Allen Probes Observations.

Quantification of energetic electron precipitation caused by wave-particle interactions is fundamentally important to understand the cycle of particle energization and loss of the radiation belts. One important way to determine how well the wave-particle interaction models predict losses through pitch-angle scattering into the atmospheric loss cone is the direct comparison between the ionization altitude profiles expected in the atmosphere due to the precipitating fluxes and the ionization profiles actually measured with incoherent scatter radars. This paper reports such a comparison using a forward propagation of loss-cone electron fluxes, calculated with the electron pitch angle diffusion model applied to Van Allen Probes measurements, coupled with the Boulder Electron Radiation to Ionization model, which propagates the fluxes into the atmosphere.

Day-to-Day Variability of the Semidiurnal Tide in the F-Region Ionosphere During the January 2021 SSW From COSMIC-2 and ICON.

The semidiurnal tidal spectrum in the F-region ionosphere obtained from hourly COSMIC-2 Global Ionospheric Specification (GIS) data assimilation is greatly (>50%) enhanced during the January 2021 Sudden Stratospheric Warming (SSW). Moreover, the semidiurnal migrating tidal response in topside electron densities closely follows the day-to-day changes of the 10 hPa, 60°N zonal wind from MERRA-2 during the SSW. The response is similar in the northern and southern crests of the Equatorial Ionization Anomaly (EIA) but persists toward higher magnetic latitudes and the EIA trough.

Resolving Vertical Variations of Horizontal Neutral Winds in Earth's High Latitude Space-Atmosphere Interaction Region (SAIR).

Few remote sensing or in-situ techniques can measure winds in Earth's thermosphere between altitudes of 120 and 200 km. One possible approach within this region uses Doppler spectroscopy of the optical emission from atomic oxygen at 558 nm, although historical approaches have been hindered in the auroral zone because the emission altitude varies dramatically, both across the sky and over time, as a result of changing characteristic energy of auroral precipitation. Thus, a new approach is presented that instead uses this variation as an advantage, to resolve height profiles of the horizontal wind.

Mechanism Studies of Madden-Julian Oscillation Coupling Into the Mesosphere/Lower Thermosphere Tides Using SABER, MERRA-2, and SD-WACCMX.

The Madden-Julian Oscillation (MJO), an eastward-moving disturbance near the equator (±30°) that typically recurs every ∼30-90 days in tropical winds and clouds, is the dominant mode of intraseasonal variability in tropical convection and circulation and has been extensively studied due to its importance for medium-range weather forecasting. A previous statistical diagnostic of SABER/TIMED observations and the MJO index showed that the migrating diurnal (DW1) and the important nonmigrating diurnal (DE3) tide modulates on MJO-timescale in the mesosphere/lower thermosphere (MLT) by about 20%-30%, depending on the MJO phase. In this study, we address the physics of the underlying coupling mechanisms using SABER, MERRA-2 reanalysis, and SD-WACCMX.

Daytime Dynamo Electrodynamics With Spiral Currents Driven by Strong Winds Revealed by Vapor Trails and Sounding Rocket Probes.

We investigate the forces and atmosphere-ionosphere coupling that create atmospheric dynamo currents using two rockets launched nearly simultaneously on 4 July 2013 from Wallops Island (USA), during daytime Sq conditions with ΔH of -30 nT. One rocket released a vapor trail observed from an airplane which showed peak velocities of >160 m/s near 108 km and turbulence coincident with strong unstable shear. Electric and magnetic fields and plasma density were measured on a second rocket.

Lidar Observations of Stratospheric Gravity Waves From 2011 to 2015 at McMurdo (77.84°S, 166.69°E), Antarctica: 2. Potential Energy Densities, Lognormal Distributions, and Seasonal Variations.

Five years of Fe Boltzmann lidar's Rayleigh temperature data from 2011 to 2015 at McMurdo are used to characterize gravity wave potential energy mass density ( ), potential energy volume density ( ), vertical wave number spectra, and static stability in the stratosphere 30-50 km. ( ) profiles increase (decrease) with altitude, and the scale heights of indicate stronger wave dissipation in winter than in summer. Altitude mean and obey lognormal distributions and possess narrowly clustered small values in summer but widely spread large values in winter.