Engineering topics
Komjathy, A.
Publications and source records attributed to Komjathy, A..
Heliosphere-Ionosphere-Thermosphere Coupling and Energy Budget in Geomagnetic Storms
No abstract available
Observing Tsunamis in the Ionosphere Using Ground Based GPS Measurements
Ground-based Global Positioning System (GPS) measurements of ionospheric Total Electron Content (TEC) show variations consistent with atmospheric internal gravity waves caused by ocean tsunamis following recent seismic events, including the Tohoku tsunami of March 11, 2011. We observe fluctuations correlated in time, space, and wave properties with this tsunami in TEC estimates processed using JPL's Global Ionospheric Mapping Software. These TEC estimates were band-pass filtered to remove ionospheric TEC variations with periods outside the typical range of internal gravity waves caused by tsunamis. Observable variations in TEC appear correlated with the Tohoku tsunami near the epicenter, at Hawaii, and near the west coast of North America. Disturbance magnitudes are 1-10% of the background TEC value. Observations near the epicenter are compared to estimates of expected tsunami-driven TEC variations produced by Embry Riddle Aeronautical University's Spectral Full Wave Model, an atmosphere-ionosphere coupling model, and found to be in good agreement. The potential exists to apply these detection techniques to real-time GPS TEC data, providing estimates of tsunami speed and amplitude that may be useful for future early warning systems.
Dayside Global Ionospheric Response to the Major Interplanetary Events of October 29-30, 2003 ''Halloween Storms''
We demonstrate extreme ionospheric response to the large interplanetary electric fields during the "Halloween" storms that occurred on October 29 and 30, 2003. Within a few (2 - 5) hours of the time when the enhanced interplanetary electric field impinged on the magnetopause, dayside total electron content increases of approx.40% and approx.250% are observed for the October 29 and 30 events, respectively. During the Oct 30 event, approx.900% increases in electron content above the CHAMP satellite (approx.400 km altitude) were observed at mid-latitudes (+/-30 degrees geomagnetic). The geomagnetic storm-time phenomenon of prompt penetration electric fields is a possible contributing cause of these electron content increases, producing dayside ionospheric uplift combined with equatorial plasma diffusion along magnetic field lines to higher latitudes, creating a "daytime super-fountain" effect.
Extreme ionospheric storms and their impact on WAAS
Satellite-based augmentation systems (SBAS) in the absence of selective availability, the ionosphere represents the largest source of positioning error for single-frequency users of the Global Positioning System (GPS).
GPS-based remote sensing of the geospace environment: horizontal and vertical structure of the ionosphere and plasmasphere
We will discuss a new data assimilation model of ionosphere, the Global Assimilative Ionosphere Model (GAIM), capable of integrating measurements from GPS and other sensors with a physics-based ionospheric model, to provide detailed global nowcasts of ionospheric structure, useful for science and applications.
Estimating SBAS ionospheric delays without grids: the conical domain approach
This paper presents an alternative model of slant delay measurements that allows direct computation of the user's slant delay estimate without the intervening use of a vertical delay grid.
On the ionospheric impact of recent storm events on satellite-based augmentation systems in middle and low-lattitude sectors
In this paper, we use GPS measurements of geomagnetic storm days to perform a quantitative assessment of WAAS-type ionospheric correction algorithms in other parts of the world such as the low-latitude Brazil and mid-latitude Europe.
An assessment and comparison of WAAS ionosheric correction algorithms in CONUS and Europe
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Characterizing the dependence of satellite-based augmentation systems upon the spatial distribution of GPS measurements
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Alternative ionospheric correction algorithms for satellite-based augmentation systems in low-latitude region
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An alternative ionospheric correction algorithm for satellite-based augmentation systems in low-latitude region
In this paper, we use data from the South American region to perform a quantitative assessment of WAAS-type ionospheric correction algorithms in this region.