Statistics of Coronal Mass Ejections for use in space weather forecasting

Forecasts of geomagnetic activity are vital for helping to protect vulnerable technological infrastructure. However, we have relatively little data with which to make a decision about the level of expected activity. Whilst advances in modelling techniques (for example, the WSA-ENLIL model) and increases in data availability are helping, there is still a knowledge gap and forecasts still depend heavily on the judgement of the forecaster. The aim of this work is to help forecasters put CMEs into context, based on past events, in a straightforward manner. We have analysed 12 years of coronal mass ejections (CMEs) from Jan 1998 to Dec 2009, focusing on the data available at the time for forecasting. CMEs which were identified as having a potential to impact the Earth are then assessed and correlated with any resulting geomagnetic activity. Here we present statistics of Earth-directed CMEs and their likelihood to cause geomagnetic storms based on near-real time data. We review parameters including CME velocity, angular width, source location and velocity, and compare our results with other related studies.