Geomagnetic storm forecasting from solar coronal holes by Simona Nitti et al. on Wednesday 30 November

Coronal holes (CHs) are the source of high-speed streams (HSSs) in the solar

wind, whose interaction with the slow solar wind creates corotating interaction

regions (CIRs) in the heliosphere. Whenever the CIRs hit the Earth, they can

cause geomagnetic storms. We develop a method to predict the strength of

CIR/HSS-driven geomagnetic storms directly from solar observations using the CH

areas and associated magnetic field polarity. First, we build a dataset

comprising the properties of CHs on the Sun, the associated HSSs, CIRs, and

orientation of the interplanetary magnetic field (IMF) at L1, and the strength

of the associated geomagnetic storms by the geomagnetic indices Dst and Kp.

Then, we predict the Dst and Kp indices using a Gaussian Process model, which

accounts for the annual variation of the orientation of Earth's magnetic field

axis. We demonstrate that the polarity of the IMF at L1 associated with CIRs is

preserved in around 83% of cases when compared to the polarity of their CH

sources. Testing our model over the period 2010-2020, we obtained a correlation

coefficient between the predicted and observed Dst index of R = 0.63/0.73, and

Kp index of R = 0.65/0.67, for HSSs having a polarity towards/away from the

Sun. These findings demonstrate the possibility of predicting CIR/HSS-driven

geomagnetic storms directly from solar observations and extending the

forecasting lead time up to several days, which is relevant for enhancing space

weather predictions.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.16572v1