Analysis of Solar Activity and Atmospheric Pressure Competition Effects on Cosmic Radiation Events

In this paper, we analyze the influence of characteristic solar activity parameters as well as the competition effects in solar activity and atmospheric pressure on the records of cosmic radiation based on HiSPARC (The High School Project on Astro physics Research with Cosmic rays), a ground-based muon detector system monitoring secondary cosmic ray intensity. We gather the data from No.501 HiSPARC station situated at Nikhef in Science Park, Amsterdam, Netherlands (52.3558963°N, 4.9509827°E, 56.18 m of altitude). The accepted anticorrelation between solar activity and the intensity of near ground cosmic ray is confirmed by comparing the number of solar flares, relative number of sunspots and counting rates of the detector. The barometric effect has been considered to correct the number of events. Furthermore, a new empirical equation is given to show the correlation between the cosmic ray intensity and the characteristic solar activity parameters, including the number, the area and the latitude of sunspot groups. As for the competition effects of solar activity and atmospheric pressure, we find there exists a threshold in detector's sensitivity to the sunspot numbers. Above the threshold, the detector is more sensitive to the atmospheric pressure rather than the solar activity. Our discovery delineating the solar activities and atmospheric pressure competition effects on the event rate can provide a different way to monitor real-time space weather and cast light on the investigation of short-term solar activity forecast.