## 4 Discussion  
By comparing the two different curves in Figure 5, their differences can be summarized in the following discussion. (1) The characteristics of the average daily variation curves in Antarctica and Beijing are obviously different; the daily variation curve of Antarctica changes by 17% of the mean AEF, while the curve of Beijing changes by 37%, and the daily variation of Beijing fluctuates even more. Their curves are represented by the following two different types: the curve in Antarctica is \"single peak, single valley\" on the whole, while the curve in Beijing is characterized by \"double peaks, double valleys,\" which are mainly determined by the local geological conditions and environmental factors. The composition and content of radioactive substances vary under the crust in different regions, and they affect atmospheric ionization, which in turn affects the state of space charge density distribution and thus disturbs the AEF. Antarctica is remote, sparsely populated, and far from aerosol sources, while Beijing is densely populated. Therefore, the curves in these regions take on two different shapes, and the average daily variation curve in Beijing is more complicated than that in Antarctica. (2) There is a significant difference in the time of peak and valley values of the two curves because of the different longitudes, which result in different sunrise and sunset times in the two regions. The sunrise and sunset times determine the intensity and time of the vertical transport of aerosols, which in turn affects the peak and valley times of the AEF daily variation curves. (3) In addition, the average fair-weather AEF value in Antarctica was 0.54 kV/m, while it was 0.17 kV/m in Beijing. Not only is the value in Antarctica 0.37 kV/m higher than that in Beijing, but this value significantly exceeds the observations made by other researchers. The authors attribute the reasons for this difference as the following: (i) there is less precipitation and lower temperature in Antarctica, and the area around the instrument is mostly ice and snow, and these conditions resulted in fewer radioactive substances and fewer charged small ions in Antarctica. (ii) The latitudinal difference between Antarctica and Beijing is a factor, because there is a certain horizontal potential difference at the bottom of the ionosphere between the polar region and middle or low latitudes. (iii) The Antarctic Chinese Zhongshan Station is located in the south auroral zone, so the ionospheric potential may be influenced by magnetospheric currents, which raises the ionospheric potential at dawn by approximately 25 kV during low magnetic activity, while lowering the nighttime ionospheric potential by approximately 25 kV. This effect would cause the AEF values in the morning to be higher and the those in the evening to be lower in Antarctica. (iv) Due to the location limitations of the Antarctic Chinese Zhongshan Station, the EFM in Antarctica is close to snow, ice, and water sources. This increases the water vapor molecules around the EFM, causing many light ions to attach to the water molecules and become heavy ions, a process that reduces the atmospheric conductivity near the ground. (v) The wind speed at the Antarctic Chinese Zhongshan Station was relatively high, with an average of more than 6 m/s at 52% of the moments, which is a much higher percentage than normal weather. High winds can carry ions of particulate matter through the air and change the distribution of space charge, which could have disturbed the AEF values in Antarctica. There are many inevitable and reasonable errors in the experimental process. First, the EFM is a method of generating induced charges and weak current through the rotation of the stator and rotor, which can be easily disturbed by environmental factors. Then, the EFM has a certain measurement accuracy, resolution, zero stability, and linearity due to the limitation of circuit components.