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Ensemble CME modelling constrained by heliospheric imager observations

Luke Barnard - University of Reading; Mathew Owens - University of Reading, United Kingdom; Chris Scott - University of Reading, United Kingdom; Curt de Koning - University of Colorado, Space Weather Prediction Center, United States

Session: Interplanetary CMEs and Solar Particle Events


Abstract

Predicting the arrival of CMEs is one key objective of space weather forecasting. In operational space weather forecasting solar wind numerical models are used for this task, and ensemble techniques are being increasingly explored as a means to improve these forecasts. Currently these forecasts are not constrained by the available in-situ and remote sensing observations, such as those from the Heliospheric Imagers (HI) on NASA's STEREO spacecraft. We report case-studies of 4 CMEs and show how HI observations can be used to improve the skill and reduce the uncertainty of ensemble hindcasts of these events. Using a computationally-efficient solar wind model, we produce 200-member ensemble hindcasts, perturbing the modelled CME parameters within uniform distributions about the best estimates. By comparing the trajectory of the modelled CME flanks with HI observations, we compute a weight for each ensemble member. Weighting the ensemble distribution of CME arrival times improves the skill and reduces the hindcast uncertainty of each event. The weighted ensembles show a mean reduction in arrival time error of 20.1±4.1%, and a reduction in arrival time uncertainty of 15.0±7.2%, relative to the unweighted ensembles. This technique could be applied in operational space weather forecasting, if real-time HI observations were available.



Approaching deadlines:

Registration opens:

16 July 2020

Abstract submission opens:

16 July 2020

European Space Weather Medals:

6 September 2020

Registration deadline:

25 September 2020

Registration deadline: [extended]

10 October 2020

Abstract submission deadline:

4 September 2020