Solar activity influences the ozone hole

he increase in greenhouse gases explains to a large extent the rise in the average earth temperature. However, fluctuations in solar activity affect the mid-atmospheric ozone and provide a potential link to regional-scale climate variability. This climate variability is not a trend of climate change, but an annual fluctuation after solar activity.

For the first time, the team confirmed the long-term effects of solar-powered electrons on high-level ozone. The results showed that polar latitudes had a strong effect. It was found that the amount of ozone at the altitude of 70-80 km varied by more than 30% over the solar cycle for about 11 years. The ozone change between extreme solar activities is very large and may affect the atmospheric temperature balance, which in turn may impact on atmospheric winds.

According to studies conducted by Finnish Meteorological Institute, University of Otago and British Antarctic Survey, analogous to the electron behind the aurora, a significant periodicity of solar activity has been created in the polar mid-layer ozone. As more electrons enter the atmosphere, the amount of ozone will decrease.

The solar wind is a stream of energetic particles (Fig. 1). Thanks to the protection of the geomagnetic layer, only a small part of solar high-energy particles traverse the Earth's magnetosphere every year and concentrate along the magnetic lines of force to the north and south poles (Liu, et al., 2015). During solar-driven magnetic storms, electrons accelerate to the polar and into the atmosphere. And then, electrons ionize gas molecules, resulting in the generation of ozone depleting catalyst gases. In the meantime, since the high-energy particles are mainly hydrogen elements, they reach the poles and most likely synthesize water with ozone. Therefore, it first destroys bipolar ozone. Based on currently available satellite observations, electronic precipitation may temporarily reduce ozone in the upper atmosphere (60-80 km) by up to 90% during a few days of solar storms.

                                 

Figure 1. Solar wind (Source: NASA).

According to calculations, the number of solar particles entering the Antarctic is 6.6% higher than that of entering the North Pole. Data also shows that in the past century, the dipole moment of geomagnetic materials was reduced by 5%, resulting in a decrease in the protection capability of the Earth and an increase in the ozone hole over the Antarctic year by year. It is also said that the ozone hole is a dynamic, natural process of drifting between poles. Since the Earth's orbit around the sun is an ellipse, the change period between the near-day and far-day points is 21,000 years. Therefore, the ozone hole is in the southern hemisphere for the half time which is 10,500 years and in the northern hemisphere for the other half. 

Based on the observations of the Antarctic Vostok Station in 1998, the possible influence of solar wind on the change of ozone density was discussed (Makarova and Shirochkov, 2001). , including the total ozone content (TOC) and the vertical component field (E) of atmospheric electric field (Frank-Kamenetsky et al., 2001). The results are shown in Figure 2.

Figure 2. Relationship between ozone concentration and magnitude of atmospheric electric field.

The correlation between [OS] and the top of the magnetosphere is about 0.6. This relatively low correlation may be explained by analyzing the total ozone content of the middle-level ozone layer. The correlation between ozone density and E is found to be close to 0.7. Therefore, the data clearly shows that the ozone density depends on the location of the top magnetosphere and the size of the atmospheric electric field. It is well known that the disturbance of solar wind causes the electric field in near-Earth space (Eliasson et al., 1996). These data confirm this relationship because of the significant correlation between the experimental values of electric field and the position of magnetosphere (r = 0.6), which is shown in Figure 3.

Figure 3. Relationship between magnitude of atmospheric electric field and magnetopause position.

Dr. Monika Andersson, research director of the Finnish Meteorological Agency, said: "These results help us better understand the long-term impact of such solar activity and its role in regional climate variability."