INVESTIGADORES
CREMADES FERNANDEZ Maria Hebe
congresos y reuniones científicas
Título:
Space weather prediction tools based on low-frequency type II radio emissions
Autor/es:
H. CREMADES; F. IGLESIAS; O. C. ST. CYR; H. XIE; M. L. KAISER; N. GOPALSWAMY
Lugar:
Cuzco
Reunión:
Congreso; X COLAGE; 2014
Institución organizadora:
Asociación Latinoamericana de Geofísica Espacial
Resumen:
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Given the
crucial consequences for Earth and its near-space activity, space
weather forecasting has been a central subject of research in the
past decades. This materializes nowadays in the rich and detailed
data sets provided by multiple experiments specifically devoted to
study the Sun-Earth connection. In this respect, coronal mass
ejections (CMEs) constitute a key phenomenon, because their arrival
to Earth and their associated MHD shocks are capable of triggering
geomagnetic storms. Since it is infeasible to predict the occurrence
of an Earth-directed CME, once it happened it is of vital importance
to ascertain its time of arrival at Earth with the best possible
accuracy. Radio emissions produced by shock waves ahead of CMEs allow
their tracking in the interplanetary (IP) medium as they drift down
in frequency when traveling away from the Sun, and thus serve as a
tool to trace forward travel times to Earth. A database of
Earth-directed events in different stages of their propagation from
Sun to Earth is built, containing (i)CME height-time information from
SOHO/LASCO coronagraph data, (ii) interplanetary (IP) shock
approximate locations derived from low-frequency type II radio
emissions detected by the Wind/WAVES experimentand, and (iii) in-situ
shock time of arrival at the ACE and/or Wind spacecraft. Based on
these, two different methods of tracking and predicting the location
of IP shocks are tested, namely the linear extrapolation to 1 AU of
type II radio emissions, and the second-order model of IP shock
propagation. The latter arises from the combination of white-light
corona, IP type II radio, and in-situ data, which is formulated on
the basis of typical propagation profiles that represent each CME's
journey toward Earth, together with important constrains on the main
parameters. We discuss results on CME-radio emission associations,
characteristics of IP propagation, and the success of the predictive
models to forecast the arrival time of shocks at Earth. This
synergistic study appears promising towards achieving better-educated
forecasts of shock arrival time solely based on data from spacecraft
located in the Sun-Earth line.