engleski

Probabilistic model for heliospheric propagation of Interplanetary Coronal Mass Ejections: Drag-based ensemble model (DBEM)

The drag-based model (DBM) for heliospheric propagation of ICMEs is a widely used simple analytical model which can predict ICME arrival time and speed at a given heliospheric distance (Vršnak et al., 2013, SolPhys). It is based on the assumption that the heliospheric propagation of ICMEs, is solely under the influence of MHD drag, where ICME propagation is determined based on CME properties as well as the properties of the ambient solar wind. The current version of the DBM is operational as part of ESA’s SSA programme (http://swe.ssa.esa.int/web/guest/graz-dbm-federated). The DBM takes into account the ICME geometry to track the whole leading edge of an ICME, and can estimate whether or not an ICME will reach the observer, and if, when and at what impact speed. However, there is a lack of uncertainty estimation for a single event, which can be established using an ensemble modeling approach. We present a newly developed Drag-Based Ensemble Model (DBEM) which takes into account the uncertainties of observation-based model input by making an ensemble, i.e. sets of n CME observations and m synthetic measurements of ambient solar wind speed and drag parameter. Using multiple model runs with different input parameters, DBEM calculates a distribution of predicted arrival times and speeds allowing to forecast the confidence in the likelihood of the ICME arrival.

CMEs, space weather

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