HR: 1340h
AN: SF53A-0726    [Abstracts]
TI: Detection and Investigation of Ionospheric Disturbances using the SCIGN Network
AU: * Lee, S
EM: lee77@purdue.edu
AF: Purdue University School of Aeronautics and Astronautics, 315 N. Grant Street, West Lafayette, IN 47907-2023
AU: Garrison, J L
EM: jgarriso@ecn.purdue.edu
AF: Purdue University School of Aeronautics and Astronautics, 315 N. Grant Street, West Lafayette, IN 47907-2023
AU: Calais, E
EM: ecalais@purdue.edu
AF: Department of Earth and Atmospheric Sciences, 550 Stadium Mall Drive Purdue University, West Lafayette, IN 47907-2051
AU: Haase, J
EM: jhaase@purdue.edu
AF: Department of Earth and Atmospheric Sciences, 550 Stadium Mall Drive Purdue University, West Lafayette, IN 47907-2051
AB: Ionospheric perturbations associated with atmospheric disturbances, such as earthquakes, large explosions, or rocket launches have been detected in the past, through filtering of dual-frequency GPS phase data. To further study these phenomena, we extract GPS data from the SCIGN network in Southern California, and attempt to identify the direction and speed of propagation, particularly for examples in which no obvious source could be identified. The processing of data from about 250 stations in the SCIGN followed three general steps. First the IEC (Integrated Electron Contents) time series was bandpass-filtered between 3 and 8 minutes. Second, the filtered time series from each pair of two SIPs (Sub-ionospheric points) were cross-correlated, to detect the degree of similarity between the perturbations, and to estimate the time of travel between the SIP. Finally, the travel times, for all pairs of SIP's for which a disturbance was detected, were used to estimate the propagation velocity (speed and direction) of the disturbance using a least squares method. An effect, which is similar to the Doppler effect, is predicted to result from the motion of the SIP during the time in which the perturbations are recorded. Since the speeds of the SIPs, due to satellite motion, are on the same order of magnitude as the propagation speed of ionospheric disturbances, an apparent shift in the observed frequency of the disturbances would result, depending upon the orientation between the propagation directions of the SIP's and the ionospheric disturbance. In addition to experimental data, recorded on 07/07/2000, simulated data was also used to validate the data processing algorithms, and to assess their sensitivity.
DE: 2427 Ionosphere/atmosphere interactions (0335)
DE: 2435 Ionospheric disturbances
DE: 2494 Instruments and techniques
DE: 0689 Wave propagation (4275)
SC: Special Focus: Advances in Data Acquisition, Management, Analysis and Display [SF]
MN: 2004 AGU Fall Meeting