Based on 11‐year's period data of the sunspot and the periodic variation of the magnetic field of the sunspot, the time series of the magnetic index of the sunspot magnetic field (MI) is established. The analysis indicates that the average period of the solar magnetic activity is about 22.2 years, but it is not a constant. In most cases, when the period is short, the magnetic index is large, corresponding to strong solar activity; when the period is long the magnetic index is small, corresponding to weak solar activity. The time series of magnetic index of the sunspot magnetic field has also a period of 80~90 years. This study shows that during the period of MI curve rising from its minimum to maximum, the solar magnetic field is southward, and the planetary magnetic lines and the Earth magnetic lines meet together. The magnetic layer is an open layer, with the solar wind entering into the Earth magnetic layer from the sunny side taking plenty of plasma, increasing the input kinetic, heat and electromagnetic energy greatly, which corresponds to the temperature increasing period in the troposphere of the Northern Hemisphere. On the other hand, during the period of MI curve descending from the maximum to minimum, the solar magnetic field is northward, same as the top of the magnetic layer direction, and the planetary magnetic lines and the Earth magnetic lines do not meet. The magnetic layer is a close layer; only a few electriferous particles can enter the Earth magnetic layer through magnetic lines, corresponding to the temperature decreasing period in the troposphere of the Northern Hemisphere.

Successive filtration and comparison show that the stratosphere air temperature in 10 hPa-layer of the Northern Hemisphere (NH) in July continuously increases, which is associated to the increases in greenhouse gases mostly CO 2 , volcanic activities, and solar activity, demonstrating the follows. (a) The increase in CO 2 concentration is largely consistent with that of the stratosphere air temperature in 10 hPa-layer of the NH in July. However, the increase in the air temperature is not in a linear pattern, during which several cooling events interrupt. The cooling events between late 1960s and late 1970s are remarkable ones and so is the one before mid 1990s. Analysis shows that these events are induced by volcanic activities and solar activity. (b) The CO 2 -free variation in the stratosphere air temperature in 10 hPa-layer of the NH is consistent with that of the solar magnetic index. The wave crests and wave troughs of the two curves are consistent in phase, and the curve of solar magnetic index leads the other slightly. In other words, when the solar magnetic pole is southward, a warming in the NH stratosphere corresponds; and on the contrary, the northward solar magnetic pole corresponds to a cooling event. The variation in solar magnetic polarity strongly impacts the variation in the stratosphere temperature.

With the development of the Chinese stock market and the continuous improvement of financial engineering technology, quantitative investment represented by the multi-factor stock selection strategy has been developing and growing in the Chinese stock market. This paper takes the quarterly data of the China Securities New Energy Vehicle Index from January 2017 to March 2021 as the research object, uses the Fama-Macbeth test to select factors, and constructs the regression equation based on the regression method. The regression equation is used to predict the stock return rate of the next quarter through the factor data of each quarter in 2020. The top 7 stocks with returns are selected to construct the investment portfolio in the way of equal-weighted capital allocation, and the investment portfolio is updated quarterly. Through the empirical test, this paper mainly draws the following three conclusions: First, the driving factors of stock return in the new energy vehicle industry mainly include the ratio of long-term debt to working capital (LTDWC), total profit growth rate (TPG), price/earnings to growth ratio (PEG), and equity turnover ratio (ET); secondly, the portfolio return based on the stock selection model in this paper is higher than the average level of the industry, and the investment return obtained is stable, suitable for investment targets; third, the new energy vehicle industry is in a period of rapid development, and the portfolio return rate is higher than the average level of A-share market. Therefore, it has huge potential investment value. This paper provides suggestions and solutions for investors' stock investment in the new energy vehicle industry.

No abstract

No abstract