Bibliography

Notice:

Clicking on the title will open a new window with all details of the bibliographic entry.
Clicking on the DOI link will open a new window with the original bibliographic entry from the publisher.
Clicking on a single author will show all publications by the selected author.
Clicking on a single keyword, will show all publications by the selected keyword.

Found 14 entries in the Bibliography.

Showing entries from 1 through 14

2021

Evaluating Auroral Forecasts Against Satellite Observations

The aurora is a readily visible phenomenon of interest to many members of the public. However, the aurora and associated phenomena can also significantly impact communications, ground-based infrastructure, and high-altitude radiation exposure. Forecasting the location of the auroral oval is therefore a key component of space weather forecast operations. A version of the OVATION-Prime 2013 auroral precipitation model (Newell et al., 2014, https://doi.org/10.1002/2014sw001056) was used by the UK Met Office Space Weather Operations Centre (MOSWOC). The operational implementation of the OVATION-Prime 2013 model at the UK Met Office delivered a 30-min forecast of the location of the auroral oval and the probability of observing the aurora. Using weather forecast evaluation techniques, we evaluate the ability of the OVATION-Prime 2013 model forecasts to predict the location and probability of the aurora occurring by comparing the forecasts with auroral boundaries determined from data from the IMAGE satellite between 2000 and 2002. Our analysis shows that the operational model performs well at predicting the location of the auroral oval, with a relative operating characteristic (ROC) score of 0.82. The model performance is reduced in the dayside local time sectors (ROC score = 0.59) and during periods of higher geomagnetic activity (ROC score of 0.55 for Kp = 8). As a probabilistic forecast, OVATION-Prime 2013 tends to underpredict the occurrence of aurora by a factor of 1.1–6, while probabilities of over 90\% are overpredicted.

Mooney, M.; Marsh, M.; Forsyth, C.; Sharpe, M.; Hughes, T.; Bingham, S.; Jackson, D.; Rae, I.; Chisham, G.;

Published by: Space Weather Published on:

YEAR: 2021 DOI: 10.1029/2020SW002688

AURORA; auroral forecasting; forecast verification; OVATION-Prime 2013; ROC scores; space weather

2020

Impacts of Lower Thermospheric Atomic Oxygen on Thermospheric Dynamics and Composition Using the Global Ionosphere Thermosphere Model

Malhotra, Garima; Ridley, Aaron; Marsh, Daniel; Wu, Chen; Paxton, Larry; Mlynczak, Martin;

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

YEAR: 2020 DOI:

2019

Understanding the Effects of Earth's Lower Atmosphere on Upper Ionospheric-Thermospheric Semi Annual Oscillation-Using GITM, MSIS and WACCM-X

The datasets that are used in these study for comparisons are GPS, GUVI, COSMIC and GRACE observations.

Malhotra, Garima; Ridley, Aaron; Marsh, Daniel; Wu, Chen; Paxton, Larry;

Published by: Published on:

YEAR: 2019 DOI:

2018

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

Temporal Variability of Atomic Hydrogen From the Mesopause to the Upper Thermosphere

We investigate atomic hydrogen (H) variability from the mesopause to the upper thermosphere, on time scales of solar cycle, seasonal, and diurnal, using measurements made by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere Ionosphere Mesosphere Energetics Dynamics satellite, and simulations by the National Center for Atmospheric Research Whole Atmosphere Community Climate Model-eXtended (WACCM-X). In the mesopause region (85 to 95\ km), the seasonal and solar cycle variations of H simulated by WACCM-X are consistent with those from SABER observations: H density is higher in summer than in winter, and slightly higher at solar minimum than at solar maximum. However, mesopause region H density from the Mass-Spectrometer-Incoherent-Scatter (National Research Laboratory Mass-Spectrometer-Incoherent-Scatter 00 (NRLMSISE-00)) empirical model has reversed seasonal variation compared to WACCM-X and SABER. From the mesopause to the upper thermosphere, H density simulated by WACCM-X switches its solar cycle variation twice, and seasonal dependence once, and these changes of solar cycle and seasonal variability occur in the lower thermosphere (~95 to 130\ km), whereas H from NRLMSISE-00 does not change solar cycle and seasonal dependence from the mesopause through the thermosphere. In the upper thermosphere (above 150\ km), H density simulated by WACCM-X is higher at solar minimum than at solar maximum, higher in winter than in summer, and also higher during nighttime than daytime. The amplitudes of these variations are on the order of factors of ~10, ~2, and ~2, respectively. This is consistent with NRLMSISE-00.

Qian, Liying; Burns, Alan; Solomon, Stan; Smith, Anne; McInerney, Joseph; Hunt, Linda; Marsh, Daniel; Liu, Hanli; Mlynczak, Martin; Vitt, Francis;

Published by: Journal of Geophysical Research: Space Physics Published on: 01/2018

YEAR: 2018 DOI: 10.1002/2017JA024998

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:

Understanding the Effects of Lower Boundary variations on the Ionosphere-Thermosphere System using GITM and WACCM-X

Malhotra, Garima; Ridley, Aaron; Marsh, Daniel; Wu, Chen; Paxton, Larry;

Published by: Published on:

YEAR: 2018 DOI:

2017

Understanding the Effects of Lower Boundary Conditions and Eddy Diffusion on the Ionosphere-Thermosphere System

Malhotra, Garima; Ridley, Aaron; Marsh, Daniel; Wu, Chen; Paxton, Larry;

Published by: Published on:

YEAR: 2017 DOI:

2014

Storm-time behaviors of O/N2 and NO variations

Algorithms have been developed to extract net nitric oxide (NO) radiances in the wavelength range of 172\textendash182\ nm from the dayside TIMED/GUVI spectrograph data and convert them to NO column density (100\textendash150\ km). The thermospheric O/N₂ column density ratios (referenced from an altitude ~135\ km with a N₂column density of 10¹⁷\ cm^-2) are also obtained from the spectrograph data. The spatial resolution of the NO and O/N₂ products along the GUVI orbit is 240\ km. The coincident O/N₂ ratio and NO column density maps during a few geomagnetic storms reveal two major features: (1) Storm-time O/N₂ depletion and NO enhancement extend from high to mid and low latitudes. They are anti-correlated on a global scale, (2) the NO enhancement covers a wider longitude and latitude region than O/N₂ depletion on a local scale. The similarity between O/N₂ depletion and NO enhancement on global scale is due to storm-time equatorward meridional wind that brings both O/N₂ depleted and NO enhanced air from high to low latitudes. The altitude dependence of the storm-time meridional wind, different peaks altitudes of the local O/N₂ and NO variations, and long life time of NO (one day or longer) may explain the different behaviors of O/N₂ and NO on a local scale.

Zhang, Y.; Paxton, L.J.; Morrison, D.; Marsh, D.; Kil, H.;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics Published on: 07/2014

YEAR: 2014 DOI: 10.1016/j.jastp.2014.04.003

geomagnetic storm; Thermospheric nitric oxide; Thermospheric O/N2 ratio

An analysis of the quiet time day-to-day variability in the formation of postsunset equatorial plasma bubbles in the Southeast Asian region

Presented is an analysis of the occurrence of postsunset Equatorial Plasma Bubbles (EPBs) detected using a Global Positioning System (GPS) receiver at Vanimo. The three year data set shows that the EPB occurrence maximizes (minimizes) during the equinoxes (solstices), in good agreement with previous findings. The Vanimo ionosonde station is used with the GPS receiver in an analysis of the day-to-day EPB occurrence variability during the 2000 equinox period. A superposed epoch analysis (SEA) reveals that the altitude, and the change in altitude, of the F layer height is \~1 standard deviation (1σ) larger on the days for which EPBs were detected, compared to non-EPB days. These results are then compared to results from the Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM), which show strong similarities with the observations. The TIEGCM is used to calculate the flux-tube integrated Rayleigh-Taylor (R-T) instability linear growth rate. A SEA reveals that the modeled R-T growth rate is 1σ higher on average for EPB days compared to non-EPB days, and that the upward plasma drift is the most dominant contributor. It is further demonstrated that the TIEGCM\textquoterights success in describing the observed daily EPB variability during the scintillation season resides in the variations caused by geomagnetic activity (as parameterized by Kp) rather than solar EUV flux (as parameterized by F_10.7). Geomagnetic activity varies the modeled high-latitude plasma convection and the associated Joule heating that affects the low-latitude F region dynamo, and consequently the equatorial upward plasma drift.

Carter, B.; Yizengaw, E.; Retterer, J.; Francis, M.; Terkildsen, M.; Marshall, R.; Norman, R.; Zhang, K.;

Published by: Journal of Geophysical Research: Space Physics Published on: 04/2014

YEAR: 2014 DOI: 10.1002/jgra.v119.410.1002/2013JA019570

equatorial plasma bubbles; GPS scintillation; Ionosphere

Storm-Time Behaviors of the Thermospheric O/N2 and NO Variations

Zhang, Yongliang; Paxton, Larry; Morrison, Daniel; Kil, Hyosub; Marsh, Daniel;

Published by: Published on:

YEAR: 2014 DOI:

2011

Verification of large-scale rapid transport in the lower thermosphere: Tracking the exhaust plume of STS-107 from launch to the Antarctic

Niciejewski, R.; Skinner, W.; Cooper, M.; Marshall, A.; Meier, R.; Stevens, M.; Ortland, D.; Wu, Q.;

Published by: Journal of Geophysical Research Published on: Jan-01-2011