Many researchers seek to prove the relationship between solar activity and changes of climate and weather on Earth. Related climate and weather phenomena were studied by Wilcox and Pittock [1,2]. Climate and weather changes have different durations. The best-known cycles are the 11.2-year solar patch cycle and the 22-year variable Hale magnetic cycle. Roberts and Olson [3] suggested that researchers turn their attention from long-term to short-term phenomena in the atmosphere attributable to changes in solar activity. These include the passage of the Earth across the sectoral boundaries of the interplanetary magnetic field. Research on this in recent decades has convincingly demonstrated that it correlates with changes in the area index of vortex (OTI) [4-6]. Indeed, the OTI correlates with processes in the Earth's magnetism and on the Sun's surface [7].

The magnetic field of the Sun is stretched out by the solar wind to form the interplanetary magnetic field (IMF). As the Sun rotates, the IMF twists into a spiral shape called the Parker spiral. The IMF is mostly directed along this spiral either away from or towards the Sun so that positive (Outward polarity) and negative (Inward polarity) IMF polarities occur [8].

The solar wind in the ecliptic plane is organized in such a way that it generally has two or four sectors per solar rotation (27 days) within which the magnetic field is pointed generally towards or away from the Sun. Sectoral boundaries observed on the Earth occur when the polarity of the interplanetary magnetic field reverses. Well defined sectoral boundaries are those boundaries for which there is good data, the reversal takes place cleanly and the intervals on either side of the boundary have a uniform field direction for about four days.

Wilcox [4] applied the method of superimposed epoch analysis to the vortex area index data, taking the day of crossing the sectoral boundaries as day zero. For the period of the winter months (November-March) of the years 1964-1970, a significant decrease of 5-6 days was observed in the vortex area index, the minimum of which was on the first day after the transition. However, the phenomenon is only noticeable in the winter months. In the northern hemisphere, Wilcox [4] also analysed the sectoral effect transitions according to the change in direction of the magnetic polarity sign (from +/- to -/+ and vice versa) and found no significant difference in their effect.

Regarding the relationship between the structure of the interplanetary magnetic field sector and the vortex area index, Arora and Padgaonkar [9] showed that the decrease of OTI at the time of crossing the sectoral boundaries was typical only for the years 1962-1972, before which (1946-1962) it increased at the time of crossing. Williams and Gerety [10] found the same for the years after 1974. The structure of the solar sector, following Ness and Wilcox [11], is illustrated in Figure 1.

Figure 1: The structure of the solar sector.

Figure 1 shows an example showing the sectors of the interplanetary magnetic field (white fields are the sectors) and their transitions (lines) for the period from 1st December to 20th December.

Interplanetary space is perceived to have a polarity directed toward the Sun for several consecutive days; and in the following days such that its polarity is directed away from the Sun. A magnetic field pointing towards the Sun has a negative sign, and a magnetic field in the opposite direction has a positive sign.

Sector boundaries are the times observed at Earth when the polarity of the interplanetary magnetic field (IMF) reverses. Well defined sector boundaries are those boundaries for which there is good data, the reversal takes place cleanly, and intervals on either side of the boundary have a uniform field direction for ~4 days.

List of the well-defined sector boundaries identified from the composite polarity (the computed daily polarity plus the inferred daily polarity replacing the missing data) daily polarity distributions by using a modified definition of the "well-defined" sector boundary. Here “+” refers to a day of outward polarity and “-” refers to a day of inward polarity.

Based on light trapping of three moth species, we found in an earlier article [12] that the sectors of the interplanetary magnetic field and their transitions influence the flying activity of three winter moth species. Catch peaks for all three species are found in the positive sector or sector boundary transitions. In the negative sector, the catch is low in all cases. No similar study was found in the literature.

We investigated in present work the possible relationship between changes in the interplanetary magnetic field sectors and light trapping of 29 caddisfly species, using collection data of Hungarian researchers.

In our study we use the data of mean magnetic field of the Sun published by the Wilcox Solar Observatory from 1980 to 2005. The solar mean magnetic field (SMMF) is the average field as observed over the entire visible disk of the Sun. A solar telescope was built in 1975 at Stanford University (Wilcox Solar Observatory - WSO) to study the organization and evolution of large-scale magnetic fields of the Sun. The WSO made daily observations of the mean solar magnetic field using a Babcock-type magnetograph which is connected to a 22.9 m vertical Littrow spectrograph [13].

The collecting sites and its geographical coordinates are presented in the Table 1.

Table 1: The Geographical Coordinates of the Collection Sites and Collection Years.

Based on the number of specimens caught we calculated the relative catch values for each species and swarming. Relative catch (RC) is the ratio of the number of specimen caught in a given sample unit of time and the average number of specimen caught in the same time unit calculated for the whole brood. The relative catch (RC) values of each species are assigned to the four sectors values of the catching nights. The interplanetary magnetic field sectors and boundaries and the corresponding relative catch values along the four sectors (-,+ and +,- and Inward polarity “-” and Outward polarity “+”) have been categorized. Then the RC values, in all the four categories, were summarized and averaged.

We performed the t-test calculations with our own program. This program can process any number of data. The program distinguishes if the squares of the standard deviations are the same or different. All results are shown in Table 4.1. The most important ones are shown in Figures.

Our results are shown in the Table 3 and Figures 2-8.

Table 3(a): Results of Examined Species in Connection with the Interplanetary Magnetic Field (Mountain Streams).

1. Wilcox JM. Solar Activity and the Weather. J Atmos Terr Phys. 1975; 37: 237-256.
2. Pittock AB. A Critical Look at Long-Term Sun-Weather Relationships. Rev Geophys. 1978; 16: 400-420.
3. Roberts WO, Olson RH. Geomagnetic Storms and wintertime 300-Mb Trough Development in the North Pacific-North America Area. J Atm Sci. 1973; 30: 135-140.
4. Wilcox JM, Sherrer PH, Savalgaard L, Roberts WO, Olson RH, Jenne RL. Influence of Solar Magnetic Sector Structure on Terrestrial Atmospheric Vorticity. J Atm Sci. 1974; 31, 581-588.
5. Hines CO, Halevy I. On the Reality and Nature of a Certain Sun-Weather Correlation. J Atmos Sci. 1977; 34: 382-404.
6. Olson RH, Roberts WO, Prince HD, Hedeman ER. Solar Plages and the Vorticity of the Earth's Atmosphere. Nature. 1978; 274:140-142.
7. Borbely E. The Relationship between the Planetary Magnetic Field and Changes in the Earth's Atmosphere. 1986; 90: 282-294.
8. Vokhmyanin MV, Ponyavin DI. Sector Structure of the Interplanetary Magnetic Field in the Nineteenth Century. Geophys Res Lett. 2013; 40: 3512-3516.
9. Arora, BR, Padgaonkar AD. Low Latitude Aeronomical Processes. COSPAR Symp Ser. 1980; 8, 241-244.
10. Williams RG, Gerety EJ. Does The Troposphere Respond To Day-To-Day Changes In Solar Magnetic Field? Nature. 1978; 275: 200-201.
11. Ness NF, Wilcox JM. Solar Origin of the Interplanetary Magnetic Field. Phys Rev Letters. 1964; 13: 461-464.
12. Nowinszky L, Puskas J, Kiss M. Connection between Interplanetary Magnetic Field and the Light-Trap Catch Of Moth Species. Trends in Entomol. 2020; 16: 43-47.
13. Scherrer PH, Wilcox JM, Svalgaard L, Duvall TL, Dittmer PH, Gustafson EK. The Mean Magnetic Field of the Sun: Observations at Stanford. Sol Phys. 1977; 54: 353-361.