Constraining the Kinematics of Coronal Mass Ejections in the Inner Heliosphere with In-Situ Signatures

We present a new approach to combine remote observations and in-situ data by STEREO/HI and Wind, respectively, to derive the kinematics and propagation directions of interplanetary coronal mass ejections (ICMEs). We use two methods, Fixed-? (F?) and Harmonic Mean (HM), to convert ICME elongations into distance, and constrain the ICME direction such that the ICME distance–time and velocity–time profiles are most consistent with in-situ measurements of the arrival time and velocity. The derived velocity–time functions from the Sun to 1?AU for the three events under study (1?–?6 June 2008, 13?–?18 February 2009, 3?–?5 April 2010) do not show strong differences for the two extreme geometrical assumptions of a wide ICME with a circular front (HM) or an ICME of small spatial extent in the ecliptic (F?). Due to the geometrical assumptions, HM delivers the propagation direction further away from the observing spacecraft with a mean difference of ≈?25°.