[Lurkina.n.Learnin]

What does the red areas and the green areas signify?

[Alas Babylon!]

According to the original report:

Red and green circles indicate magnitudes of GIC into and out of transformers from the ground.

From the JASON (advisory group)document, "Impacts of Severe Space Weather on the Electric Grid", Page 58.

a PDF document from the MITRE Corporation.