DBPapers

ON THE SOLAR ENERGETIC EVENTS, NEURAL NETWORKS AND FORECASTS OF GEOMAGNETIC ACTIVITY

AUTHOR/S: P. HEJDA, J. BOCHNICEK, F. VALACH, M. REVALLO
Sunday 1 August 2010 by Libadmin2009

9th International Multidisciplinary Scientific GeoConference - SGEM2009, www.sgem.org, SGEM2009 Conference Proceedings/ ISBN 10: 954-91818-1-2, June 14-19, 2009, Vol. 1, 685-692 pp

ABSTRACT

The causes of geomagnetic disturbances are either high velocity streams of solar wind
originating in coronal holes or coronal mass ejections related to solar energetic events.
In this presentation we will concentrate on the second case.
Data concerning solar energetic events, published by the USAF/NOAA in the form of
daily reports, have been collected since 1996. An analysis of ten years long data
collection has shown that the degree of the geoeffectiveness of energetic events depends
not only on their size and on their solar disc location but also on the fact whether the
events are associated with type II and IV radio bursts (RSP II and RSP IV). The
disappearance of solar filament (DSF) turned out to be a poor indicator of geomagnetic
disturbances.

The geoeffectiveness of solar energetic events associated with RSP II and/or RSP IV
has been estimated using the artificial neural network, created on the basis of the above
analysis. The successfulness of forecasts depended on the flare class and on the
combination of radio-burst types. In the case of RSP IV, 58% of the forecasted
geomagnetic responses of X-ray flares of at least B class were successful. At last, we
have studied whether the neural network will do better, if information on the flux of
high-energy protons (HEPF) is included in the input data. It was found that the output
data are more accurate, if a significant enhancement of the HEPF was observed in the
10-hour window commencing 12 hours after the appearance of the XRA.

The Geomagnetic Department of the Geophysical Institute, Prague has been issuing
daily forecasts of geomagnetic activity since 1994. Weekly forecasts began in spring
1995. Since 1996 the short term forecasts have been sent to the Czech TV. They are
presented in the frame of Weather Forecast and displayed on the web pages of the
Czech TV. The forecasts as well as reports of the actual state of the geomagnetic field in
our region are also presented on the web server of Regional Warning Centre Prague.

Keywords: solar energetic events, solar radio bursts, solar energetic proton flux, geomagnetic activity, artificial neural network, regional warning centres