摘要：Space weather forecasting is important for mitigating the risks that the effects of the near-Earth space environment have on man-made systems. Here we investigate an innovative technique for extending the temporal range of solar wind–based forecast models by using solar wind measurements made azimuthally ahead of Earth in the Parker spiral near 1 AU. Cross correlations between STEREO (near 1 AU) and ACE (at L1) solar wind quantities are examined for a 1 year period during the most recent solar minimum, and we show that data from STEREO-B, which is azimuthally behind Earth in its orbit but ahead of Earth in the Parker spiral, can be used as an input to a relativistic electron forecast model to extend its capability to +6 days from its original range of +2 days. We show that this extended forecast performs better than simple persistence or average models for all 6 forecast days. We also compare +1 day solar wind speed forecasts using offset STEREO-B data and the Wang-Sheeley-Arge model, and we find that the offset STEREO-B data performs significantly better for estimating the future solar wind at Earth during the investigation period. We conclude that this technique could be particularly beneficial to space weather forecasting and argue for a permanent solar wind monitor at the fifth Lagrange point in the Sun-Earth system.
