Comparison of the in situ observations at Earth and the modelled velocity (top panel) and density time series (bottom panel) obtained in EUHFORIA simulations, for the cases of Earth, at zero degrees longitude and latitude, in the case of Event 1. The in situ data are presented as the green line and the modelled time series have different line styles according to the fitting that they present. We also include with the blue curve the results for Earth, for the case of the DONKI parameters. The modelling results were obtained using the CME characteristics obtained from the GCS fittings (Sect. 3.1.2). The red arrow indicates the observed arrival time of the disturbance at Earth. The blue arrow indicates the estimated arrival time from the measurements of the radio observations. The majority of the modelled Earth arrival times are late in comparison with observations, but they gradually shift towards the observed time as we go from GCS1 up to GCS4 and reconstruct the CME at larger heights. The observed Δt is different for different latitudes, ranging from 20 mins to 20 h.