Keywords: 
• 晴天大气电场 /
• 气象效应 /
• 太阳日周期调制

Abstract: Based on the fair weather atmospheric electric field recorded by YBJ Cosmic Ray Station located at the YBJ High Altitude Cosmic Ray Laboratory （90° 31＇50＂ E, 30° 06＇38＂ N, 4300 m a.s.l., 606 g/cm2）, Tibet, China, its meteorological effects and time variations are studied. The analysis in this paper is to look into how the factors like atmospheric pressure, temperature and relative humidity in the presence of the meteorological factors in four seasons govern the fair weather atmospheric electric field at the site of measurement. The results of meteorological effects show that there is a strong positive correlation between the fair weather atmospheric electric field and temperature, while a moderate positive correlation is seen between the fair weather atmospheric electric field and the atmospheric pressure, also the relative humidity. The long-term variations of the fair weather atmospheric electric field are affected by seasons. The mean value is higher in summer and fall, but lower in winter and spring. The daily variation of the fair weather atmospheric electric field is modulated by solar diurnal, semi-solar diurnal, and its third and fourth harmonic component. The higher the harmonic frequency, the lower the modulate amplitude is. The daily variation curves show bimodal variation with evening peak and sunrise peak. Two minima can also be seen in early morning and evening. Sunrise peak value is highest during summer and fall, but lowest in spring and winter morning. Sunrise peak occurs at around noon, and evening peak is modulated by the season effects.