The sun has a year that varies from 10 to 12 earth years. For this research this sun year is referred to as the "sol-year" and begins with the earth year that the sunspot minimum occurs. The Sun orbits around the center of rotation of the solar system. This orbit takes 10 to 12 earth years to complete. During this orbit the sun goes through the solar cycle where the sunspots are at their minimum to the maximum and back again to the minimum. While the sun makes its orbit the earth is orbiting around the sun and the large scale circulation patterns of the earth experience some of the same influences as the sun.
The Solar Cyclone Strike Index is made up of cycles and phases. The cycles are the sol-years and range from 10 to 13 earth years. Phase 1 of the index is each earth year when the sunspot minimum occurred and Phase 2 is each earth year one year past the minimum etc. The tracks of North Atlantic tropical storms and hurricanes where then grouped into the Solar Cyclone Strike Index (SCSI).
Each phase of the index is then summarized and landfall along the United States coastlines then compared. The highest two probabilities for each section of the coast were considered to have the highest risk of a storm strike.