A5066533681- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Earthquake Detection and Analysis
- Geophysics and Gravity Measurements
- GNSS positioning and interference
- Geomagnetism and Paleomagnetism Studies
- Meteorological Phenomena and Simulations
- Atmospheric Ozone and Climate
- Remote Sensing in Agriculture
- SARS-CoV-2 and COVID-19 Research
- Electron and X-Ray Spectroscopy Techniques
- Astro and Planetary Science
- Remote Sensing and LiDAR Applications
- Lightning and Electromagnetic Phenomena
- COVID-19 Clinical Research Studies
- Oceanographic and Atmospheric Processes
- Calibration and Measurement Techniques
- Plasma Diagnostics and Applications
- Spectroscopy and Chemometric Analyses
- Advanced Thermodynamics and Statistical Mechanics
- Remote-Sensing Image Classification
- Climate variability and models
- Species Distribution and Climate Change
- Advancements in Photolithography Techniques
- Cosmology and Gravitation Theories
United States Naval Research Laboratory
2015-2024
Naval Research Laboratory Space Science Division
2004-2024
Queen's University
2024
United States Navy
2009-2023
International Severe Acute Respiratory and Emerging Infection Consortium
2023
St Mary's Hospital
2023
St Thomas' Hospital
2022
Illinois Institute of Technology
2021
Archer Daniels Midland (United States)
2020
United States Department of the Navy
2009
The Horizontal Wind Model (HWM) has been updated in the thermosphere with new observations and formulation changes. These data are ground‐based 630 nm Fabry‐Perot Interferometer (FPI) measurements equatorial polar regions, as well cross‐track winds from Gravity Field Steady State Ocean Circulation Explorer (GOCE) satellite. GOCE wind provide valuable twilight regions. FPI fill latitudinal gaps prior observational database. Construction of this reference model also provides opportunity to...
The day‐to‐day variability in ionospheric irregularity generation giving rise to equatorial scintillation has remained an unresolved issue over many decades. We take a fresh look at the problem utilizing global imagery provided by Global Ultraviolet Imager (GUVI) instrument on NASA's Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics satellite. GUVI been acquiring images of 135.6‐nm emission Earth's ionosphere‐thermosphere system since 2001. These disk dusk have used identify cases...
Abstract We present a statistical attribution analysis of the changes in global annual average thermospheric mass density and ionospheric total electron content (TEC) between cycle 22/23 solar minimum (which occurred at epoch 1996.4) prolonged 23/24 (2008.8). The data are derived from orbital drag, TEC ground‐based GPS receivers. interminima change was −36% relative to 1996.4 yearly average. Considering each multiplicative forcing independently, lower geomagnetic activity during produced an...
Abstract We have performed simulations using the Naval Research Laboratory's physics‐based model of ionosphere, Sami3 is A Model Ionosphere (SAMI3), to illustrate how neutral wind dynamics responsible for day‐to‐day variability ionosphere. used winds specified from extended version Whole Atmosphere Community Climate (SD‐WACCM‐X), in which meteorology below 92 km constrained by atmospheric specifications an operational weather forecast and reanalysis. To assess realism against observations,...
Abstract Recent advances in developing accurate, physics‐based models of the coupled ionosphere‐thermosphere (CIT) system have now made these an integral part next‐generation space weather prediction capabilities. These produced a better understanding how CIT is affected by variability neutral lower atmosphere. However, impacts on atmospheric over time scales with characteristic periods longer than ~10 days received little attention, despite clear evidence this circulation patterns...
Abstract We use a new data product of electron column density (total content, or TEC) maps to estimate and attribute the interminimum changes (the differences between annual averages centered on 2008 1996 solar minima) in TEC global hemispheric (dividing globe three different ways). observed corresponding geomagnetic activity. The map was constructed with temporally consistent processing, it resolves some apparent inconsistencies earlier studies. estimated average change is −19.3% ± 1.0% (2...
Abstract It is well‐known that equatorial plasma bubbles (EPBs) are highly correlated to the post‐sunset rise of ionosphere on a climatological basis. However, when proceeding daily EPB development, what controls day‐to‐day/longitudinal variability EPBs remains puzzle. In this study, we investigate underlying physics responsible for using Sami3 A Model Ionosphere (SAMI3) and Specified Dynamics Whole Atmosphere Community Climate with thermosphere‐ionosphere eXtension (SD‐WACCM‐X). Simulation...
Abstract The International Reference Ionosphere (IRI) model is widely used in the ionospheric community and considered gold standard for empirical models. development of this was initiated late 1960s using FORTRAN language; its programming approach, outputs were calculated separately each given geographic location time stamp. Consultative Committee on Radio (CCIR) Union Science (URSI) coefficients provide skeleton IRI model, as they define global distribution maximum useable frequency fo F2...
Abstract We analyze the effects specified dynamics (SD) and 4D Tendency nudging have on accurately reproducing middle upper atmospheric variability induced by 2010 sudden stratospheric warming (SSW) event in National Center for Atmospheric Research thermosphere‐ionosphere‐mesosphere‐electrodynamics general circulation model (TIME‐GCM). TIME‐GCM numerical experiments were performed using constrained winds temperatures from a high‐altitude version of Navy Global Environmental Model to compare...
Abstract In order to assess current modeling capability of reproducing storm impacts on total electron content (TEC), we considered quantities such as TEC, TEC changes compared quiet time values, and the maximum value during a storm. We obtained from ionospheric models against ground‐based GPS measurements 2006 AGU event (14–15 December 2006) in selected eight longitude sectors. used 15 simulations models, including empirical, physics‐based, coupled ionosphere‐thermosphere, data assimilation...
Observations performed with the Low Resolution Airglow and Aurora Spectrograph (LORAAS), which flew aboard Advanced Research Global Observation Satellite (ARGOS), show evidence of wave number four longitudinal variations in nighttime equatorial anomaly during March 2001 2002. LORAAS limb scans O I 135.6 nm emission features are used to reconstruct electron density profiles from maps monthly average peak F region densities heights at 0230 LT generated. The structure is nearly identical both...
Abstract For nine of the strongest geomagnetic storms in solar cycle 24 we characterize, quantify, and compare impacts on ionospheric total electron content (TEC) U.S. Wide Area Augmentation System (WAAS) with heliospheric morphology kinematics responsible coronal mass ejections (CMEs) their source regions. Regional TEC responses to events are similar many respects, especially initial positive phase. subsequent negative phase, Dst is a better indicator than ap magnitude decrease. The five...
It is known that there exists a linear relationship between the maximum velocity of prereversal enhancement (PRE) E × B drift and strength equatorial ionization anomaly (EIA) crests at night. This can be particularly useful in event only one quantities observed. But it important to understand drivers order determine its range validity. In this study, we use SAMI2 model ionosphere together with measurements vertical Jicamarca show daytime drifts significantly affect slope linearity...
Abstract Satellite drag data showing significant (20%) short‐term variations in atmospheric mass density are presented. These data, along with the Naval Research Laboratory SAMI3 (Sami3 is Also a Model of Ionosphere) ionosphere/plasmasphere model and WACCM (Whole Atmosphere Community Climate Model) atmosphere used to estimate day‐to‐day variability thermosphere composition, winds, exosphere temperatures effect this on plasmasphere refilling rates. This assessment guided by modeling that...
The Ionospheric Data Assimilation Four-Dimensional (IDA4D) technique has been coupled to Sami3, which is another model of the ionosphere (SAMI3). In this application, ground-based and space-based GPS total electron content (TEC) data have assimilated into SAMI3, while in-situ densities, autoscaled ionosonde NmF2, reference stations used for validation. IDA4D/SAMI3 shows that night-time ionospheric localized enhancements (NILE) are formed following geomagnetic storms in November 2003 August...
Abstract This study focuses on understanding what drives the previously observed deep nighttime ionospheric hole in American sector during January 2013 sudden stratospheric warming (SSW). Performing a set of numerical experiments with thermosphere‐ionosphere‐mesosphere‐electrodynamics general circulation model (TIME‐GCM) constrained by high‐altitude version Navy Global Environmental Model, we demonstrate that this was result increased poleward and down magnetic field line plasma motion at...
Large-scale wave structure (LSWS) in the bottomside F layer is pivotal developing equatorial plasma bubbles (EPBs), potentially serving as a precursor of EPBs. Gravity waves, hypothesized to contribute through wind dynamo mechanism, face experimental challenges. This study, utilizing coupled SAMI3 and SD-WACCM-X models, investigates role gravity effect LSWS development. We found that waves originating from lower atmosphere induce vertical E×B drift perturbations nighttime...
Abstract Realistic modeling of the dynamics and variability in upper mesosphere lower thermosphere (UMLT) is critical to understand coupling between different layers whole atmosphere system. Here we present simulations UMLT temperatures at ∼100 km altitude for one year during 2014 by Whole Atmosphere Community Climate Model with thermosphere‐ionosphere extension (WACCM‐X) constrained below ∼90 using meteorological analysis products high‐altitude version Navy Global Environmental (NAVGEM‐HA)....
Abstract In this work we quantify the representation error of algorithm Estimating Model Parameters from Ionospheric Reverse Engineering (EMPIRE), which estimates global neutral winds and ion drifts given time‐varying plasma densities. SAMI3 (Sami3 is A Ionosphere) serves as background climate model pseudo‐measurements for EMPIRE observation system. This configuration allows data assimilation inputs to be self‐consistent between each other with validation data. The estimated are compared...
Abstract. Recent advances in atmospheric observations and modeling have enabled the investigation of thermosphere–ionosphere interactions as a whole-atmosphere problem. This study examines how dynamical variability middle atmosphere (MA) affects intra-day changes thermosphere ionosphere. Specifically, this investigates ionosphere–thermosphere during different time periods January 2013 using Specified Dynamics Whole Atmosphere Community Climate Model, eXtended version (SD-WACCM-X), coupled to...
Hyperion, a hyperspectral sensor, and the Advanced Land Imager (ALI) are carried on NASA's EO-1 satellite. The Evaluation Validation of for Sustainable Development (EVEOSD) is our project supporting mission. With 10% world's forests second largest country by area in world, Canada has natural requirement effective monitoring its forests. Eight test sites have been selected EVEOSD, with seven one US. Extensive fieldwork conducted at four these sites. A comparison made forest classification...