  EUropean Heliospheric FORecasting Information Asset (EUHFORIA) is a
physics-based data-driven solar wind and CME propagation model designed for
space weather forecasting and event analysis investigations. Although EUHFORIA
can predict the solar wind plasma and magnetic field properties at Earth, it is
not equipped to quantify the geoeffectiveness of the solar transients in terms
of the geomagnetic indices like the disturbance storm time (Dst) index and the
eauroral indices that quantify the impact of the magnetized plasma encounters
on Earth's magnetosphere. Therefore, we couple EUHFORIA with the Open Geospace
General Circulation Model (OpenGGCM), a magnetohydrodynamic model of the
response of Earth's magnetosphere, ionosphere, and thermosphere, to transient
solar wind characteristics. In this coupling, OpenGGCM is driven by the solar
wind and interplanetary magnetic field obtained from EUHFORIA simulations to
produce the magnetospheric and ionospheric response to the CMEs. This coupling
is validated with two observed geoeffective CME events driven with the
spheromak flux-rope CME model. We compare these simulation results with the
indices obtained from OpenGGCM simulations driven by the measured solar wind
data from spacecraft. We further employ the dynamic time warping (DTW)
technique to assess the model performance in predicting Dst. The main highlight
of this study is to use EUHFORIA simulated time series to predict the Dst and
auroral indices 1 to 2 days in advance, as compared to using the observed solar
wind data at L1, which only provides predictions 1 to 2 hours before the actual
impact.
