Analysis of 42 years of Cosmic Ray Measurements by the Neutron Monitor at Lomnick\'y st\'it Observatory

TL;DR

This study analyzes 42 years of neutron monitor data from Lomnický štít Observatory to explore relationships between cosmic rays, solar activity, and geomagnetic fields, providing a valuable dataset and insights for space weather prediction.

Contribution

It presents the first publicly accessible 42-year dataset of neutron monitor data, validates it through event identification, and investigates correlations and predictive potential for space weather modeling.

Findings

Significant anti-correlation between cosmic rays and solar radio flux (-0.74)

Better correlation with geomagnetic field when applying a 7-21 hour delay

Prediction power score of 0.22 suggests potential for real-time geomagnetic storm prediction

Abstract

The correlation and physical interconnection between space weather indices and cosmic ray flux has been well-established with extensive literature on the topic. Our investigation is centered on the relationships among the solar radio flux, geomagnetic field activity, and cosmic ray flux, as observed by the Neutron Monitor at the Lomnick\'y \v{s}t\'it Observatory in Slovakia. We processed the raw neutron monitor data, generating the first publicly accessible dataset spanning 42 years. The curated continuous data are available in .csv format in hourly resolution from December 1981 to July 2023 and in minute resolution from January 2001 to July 2023 (Institute of Experimental Physics SAS, 2024). Validation of this processed data was accomplished by identifying distinctive events within the dataset. As part of the selection of events for case studies, we report the discovery of TGE-s visible in the data. Applying the Pearson method for statistical analysis, we quantified the linear correlation of the datasets. Additionally, a prediction power score was computed to reveal potential non-linear relationships. Our findings demonstrate a significant anti-correlation between cosmic ray and solar radio flux with a correlation coefficient of -0.74, coupled with a positive correlation concerning geomagnetic field strength. We also found that the neutron monitor measurements correlate better with a delay of 7-21 hours applied to the geomagnetic field strength data. The correlation between these datasets is further improved when inspecting periods of extreme solar events only. Lastly, the computed prediction power score of 0.22 for neutron flux in the context of geomagnetic field strength presents exciting possibilities for developing real-time geomagnetic storm prediction models based on cosmic ray measurements.