Implementing 3D Geometry of a Coronal Mass Ejection in the Drag‐Based Model

Abstract The drag‐based model (DBM) is a simple and widely used analytical tool for predicting the arrival time and speed of interplanetary coronal mass ejections (ICMEs) throughout the heliosphere. The current DBM is two‐dimensional; we extend it to three dimensions by applying a non‐self‐similar cone geometry in both the equatorial and meridional planes. Tests on synthetic samples reveal clear differences between the 2D and 3D implementations, with the latter providing more accurate arrival predictions. Application to real CME‐ICME pairs shows improvement over the 2D version, though smaller than expected, likely due to sample bias and input uncertainties. The key advantage of the 3D DBM is its enhanced hit/miss analysis, especially for CMEs with latitudes away from the ecliptic plane. In terms of arrival time, the most notable improvement is the removal of the 2D DBM's systematic underestimation of ICME transit times. Finally, both 2D and 3D DBM were found to perform similarly to other forecast models.