Solar activity parameters do no longer follow each other: What happens in the solar atmosphere?

Abstract

Abstract

The Sun experienced a period of unprecedented activity during solar cycle 19 in 1950s and 1960s, now called the Modern Maximum (MM). The decay of the MM has changed the Sun, the heliosphere and the planetary environments in many ways. Here we study if this decay has proceeded synchronously in all solar parameters. We find that the 10.7cm radio flux has increases relative to sunspot numbers from 1970s to 2010s. We also find that other solar parameters like solar UV irradiance also increased with respect to the sunspot number, indicating a difference in the long-term evolution in chromospheric and photospheric parameters. These results give evidence for important structural changes in solar magnetic fields and solar atmosphere during the decay of the MM when solar activity weakened considerably. We also discuss the implication of these changes to the long-term evolution of the Earth's ionosphere.