 |
| Titel |
Statistical correlation of spectral broadening in VLF transmitter signal and low-frequency ionospheric turbulence from observation on DEMETER satellite |
| VerfasserIn |
A. Rozhnoi, M. Solovieva, O. Molchanov, O. Akentieva, J. J. Berthelier, M. Parrot, P. F. Biagi, M. Hayakawa |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1561-8633
|
| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 8, no. 5 ; Nr. 8, no. 5 (2008-10-16), S.1105-1111 |
| Datensatznummer |
250005773
|
| Publikation (Nr.) |
 copernicus.org/nhess-8-1105-2008.pdf |
|
|
|
|
|
| Zusammenfassung |
In our earlier papers we have found the effect of VLF transmitter signal
depression over epicenters of the large earthquakes from observation on the
French DEMETER satellite that can be considered as new method of global
diagnostics of seismic influence on the ionosphere. At present paper we
investigate a possibility VLF signal-ionospheric turbulence interaction
using additional characteristic of VLF signal-spectrum broadening. This
characteristic is important for estimation of the interaction type: linear
or nonlinear scattering. Our main results are the following:
– There are two zones of increased spectrum broadening, which are centered
near magnetic latitudes Φ=±10° and Φ=±40°. Basing on the previous case study research and ground ionosonde
registrations, probably it is evidence of nonlinear (active) scattering of
VLF signal on the ionospheric turbulence. However occurrence rate of
spectrum broadening in the middle-latitude area is higher than in the
near-equatorial zone (~15–20% in comparison with ~100% in
former area) that is probably coincides with the rate of ionospheric
turbulence.
– From two years statistics of observation in the selected 3 low-latitude
regions and 1 middle-latitude region inside reception area of VLF signal
from NWC transmitter we find a correlation of spectrum broadening neither
with ion-cyclotron noise (f=150–500 Hz), which possibly means poor
representation of the turbulence by the noise due to its mixture with
natural ELF emission (which correlates with whistler), nor with magnetic
storm activity.
– We find rather evident correlation of ion-cyclotron frequency noise, VLF
signal depression and weak correlation of spectrum broadening with
seismicity in the middle-latitude region over Japan. But in the low-latitude
regions we do not find such a correlation. Statistical decrease of VLF
signal supports our previous case study results. However rather weak
spectrum broadening-seismicity statistical correlation means probably that
passive scattering prevails upon nonlinear (active) one. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|