Research Highlights

Research Highlights

A selection of highlights culled from publications by HAO staff.

3D magnetic evolution of an erupting pseudostreamer

Magnetofrictional Modeling of an Erupting Pseudostreamer

In this study, we present a magnetic conguration of an erupting pseudostreamer observed on April 19, 2015 on the Southwest limb embedding a prominence cavity. The eruption resulted in a relatively wide CME with a round front and prominence core intersected by a sharp plume.

High S4 occurrence (> 0.2) longitudinal and annual variations from 2010 to 2013

COSMIC Observation of Stratospheric Gravity Wave and Ionospheric Scintillation Correlation

A correlation study is performed to investigate possible connections between the stratospheric gravity waves and the ionospheric plasma bubble induced GPS signal scintillations.

Daily average WACCMX+DART NO profiles

NO transport via Lagrangian Coherent Structures into the top of the polar vortex

The energetic particle precipitation (EPP) indirect effect (IE) refers to the downward transport of reactive odd nitrogen (NOx=NO+NO2) produced by EPP (EPP-NOx) from the polar winter mesosphere and lower thermosphere to the stratosphere where it can destroy ozone. Previous studies of the EPP IE examined NOx descent averaged over the polar region, but the work presented here considers longitudinal variations.

Histogram of small-scale GWs’ parameters observed by All-sky OH airglow imager at Resolute Bay Observatory

Characteristics of small-scale gravity waves in the Arctic winter mesosphere

Observational datasets in the polar middle atmosphere are extremely valuable for understanding the polar dynamics and coupling between lower and middle atmosphere. Using the long-term datasets observed with an OH all-sky imager, a Fabry-Perot Interferometer at Resolute Bay observatory, Canada (74.7°N, 94.9°W), and Microwave Limb Sounder and reanalysis data, we study the characteristics of small-scale gravity waves (GWs) with the horizontal wavelength less than 20 km in the Arctic winter mesosphere during 2014-2016.

The difference between zonal wind field in the NR and the prior ensemble mean of OSSEs at 0000 UT of December 31

The impact of ICON/MIGHTI zonal and meridional winds on upper atmosphere weather specification in a whole atmosphere data assimilation system

The thermospheric data assimilation is limited due to the lack of continuous observation of the neutral state. Recently, the thermospheric wind data from the Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) on NASA's Ionospheric CONnection (ICON) became available.

Snapshots during splitting of a 6-degree toroidal ring into two, overlaid in white arrow-vectors on the colormap

Dynamical Splitting Of A Spot-producing Magnetic Ring In A Nonlinear Shallow-water Model

We explore the fundamental physics of narrow toroidal rings during their nonlinear magnetohydrodynamic evolution at tachocline depths.

Comparison of observations (black squares) to SAMI3/WACCM-X results (red crosses)

Post-midnight O+ Depletions Observed by ICON: Data/Model Comparison

The NASA Ionosphere Connection explorer was launched in October 2019 with the goal of understanding the transition from Earth's atmosphere to space by measuring key quantities at low latitudes. On 23 December 2019, the Ion Velocity Meter (IVM) instrument on the ICON satellite measured large depletions in the O+ density and downward drifts in the post-midnight/pre-sunset time sector. Interestingly, the H+ density was not depleted during this time and remained relatively uniform.

Doppler frequency shifts

Probing the Solar Meridional Circulation using Fourier Legendre Decomposition

We apply the helioseismic methodology of Legendre Function Decomposition to 88 months of Dopp- lergrams obtained by the Helioseismic and Magnetic Imager (HMI) as the basis of inferring the depth variation of the mean meridional flow, as averaged between 20 and 60 degrees latitude and in time, in both the northern and southern hemispheres.

Simulated thermosphere and ionosphere temperatures at 300 km in the 1960s, thermosphere mass density at 400 km in the 1960s, and their changes from the 1960s to 2010s, at 17UT

Climate Changes in the Upper Atmosphere: Contributions by the Changing Greenhouse Gas Concentrations and Earth's Magnetic Field From the 1960s to 2010s

Previous studies have established the importance of the increasing greenhouse gas concentrations in causing trends in the thermosphere and ionosphere (T-I). Recent work indicates that the changing Earth’s magnetic field is also important. We conduct whole atmosphere model simulations to examine T-I trends driven by these two drivers and their relative importance.