Research Highlights

Research Highlights

A selection of highlights culled from publications by HAO staff.

(a) Root mean square error and (b) bias in WACCMX+DART experiments compared to ground-based Global Navigation Satellite System (GNSS) total electron content observations for the 1 hr forecast (F) and analysis (A)

Assimilation of Ionosphere Observations in the Whole Atmosphere Community Climate Model with thermosphere-ionosphere eXtension (WACCMX)

The Earth’s upper atmosphere impacts a wide range of technologies, including satellite communication and navigation signals. Specification and forecasting of the upper atmosphere are critical for mitigating these effects. Improved specification of the state of the upper atmosphere can also improve scientific understanding of this region.

Height vs. latitude structures of Q6DW zonal wind amplitudes

Planetary wave (PW) generation in the thermosphere driven by the PW-modulated tidal spectrum

The National Center for Atmospheric Research thermosphere-ionosphere-electrodynamics general circulation model (TIE-GCM) is used to conduct numerical experiments that isolate and elucidate a substantial modication of the quasi-6-day wave (Q6DW) above 110 km due to presence of the planetary wave (PW) modulated tidal spectrum.

Examples of various initial GLOW configurations

Convolutional Neural Networks for Predicting the strength of the Near-Earth Magnetic Field Caused by Interplanetary Coronal Mass Ejections

In this paper, regression-based deep convolutional neural networks (CNN), with 12 layers, are developed for predicting the maximal amplitude of the southward component of the near-Earth magnetic field from a passing interplanetary coronal mass ejection (ICME).

A comparison of 1D and 3D calculations of the brightness of Ca II K (top row), Mg II k (middle row) and H Lα (bottome row), computed as for the k line images, at the Doppler shifts shown

On the Cores of Resonance Lines Formed in the Sun's Chromosphere

We re-examine a 50+ year-old problem of deep central reversals predicted for strong solar spectral lines, in contrast to the smaller reversals seen in observations.

The simulated vertical E x B drift velocity (Wi), and the changes of the vertical drift velocity due to the flares, at 300 km and12:00 LT (September 6th – September 11th, 2017)

Responses of the Thermosphere and Ionosphere System to Concurrent Solar Flares and Geomagnetic Storms

We conducted numerical simulations to examine dayside thermosphere and ionosphere responses to concurrent solar flares and a geomagnetic storm during September 6th – September 11th, 2017, as well as the interplay of flare and storm effects. We found that E-region electron density response to the flares was much smaller inside the auroral oval than it was outside the auroral oval due to an extra source of ionization by auroral particle precipitation.

Line profiles of He I and He II resonance lines are shown as a function of wavelength (and equivalent Doppler shift) and time, computed from a coronal initial state

Neutral hydrogen, helium and solar and stellar coronae

In the context of the solar atmosphere, we re-examine the role of of neutral and ionized species in dissipating the ordered energy of intermediate-mode MHD waves into heat. We solve conservation equations for the hydrodynamics and for hydrogen and helium ionization stages, along closed bundles of magnetic field.

Retrograde and prograde Rossby waves

Physics Of MHD Rossby Waves In The Sun

Evidence of the existence of hydrodynamic and MHD Rossby waves in the Sun is accumulating rapidly. We employ an MHD Rossby wave model for the Sun in simplified Cartesian geometry, with a uniform toroidal field and no differential rotation, to analyze the role of each force that contributes to Rossby wave dynamics, and compute fluid particle trajectories followed in these waves.

Altitude (50-260 km) versus MJO phase depiction of DE3 (a), UFKW (b), DW1 (c), and SW2 (d) low-latitude (±40°) zonal wind amplitudes obtained applying a composite analysis method to three hourly 1980-2017 SD/WACCM-X output

Preliminary Evidence of Madden-Julian Oscillation Effects on Ultra-Fast Tropical Waves in the Thermosphere

Over the past two decades mounting evidence demonstrated that terrestrial weather significantly influences the dynamics and mean state of the thermosphere. While important progress has been made in understanding how this coupling occurs on hourly to daily time scales, large uncertainty still exists on this effect around intraseasonal (∼30–90 days) time scales.

Comparison of 135.6 nm emissions from the SAMI3/WACCM-X simulation for the March case (left and middle panels) and GOLD emission data (right panel) observed from geosynchronous orbit [Eastes et al., 2019]

Global Modeling of Equatorial Spread F with SAMI3/WACCM-X

We report the first results of a global ionosphere/thermosphere simulation study that self-consistently generates large-scale equatorial spread F (ESF) plasma bubbles in the post-sunset ionosphere. The coupled model comprises the ionospheric code SAMI3 and the atmosphere/thermosphere code WACCM-X.