# Deriving the solar activity cycle modulation on cosmic ray intensity observed by Nagoya muon detector from October 1970 until December 2012

## TL;DR

This study analyzes over 40 years of Nagoya muon detector data to understand how solar activity cycles modulate cosmic ray intensity, accounting for temperature effects and detector issues.

## Contribution

It presents a comprehensive analysis of long-term muon data, removing non-natural influences to reveal solar cycle modulation effects on cosmic rays.

## Key findings

- Identification of solar cycle modulation in muon data
- Effective removal of temperature and detector effects
- Preliminary evidence of solar cycle influence over 40 years

## Abstract

It is well known that the cosmic ray intensity observed at the Earth's surface presents an 11 and 22-yr variations associated with the solar activity cycle. However, the observation and analysis of this modulation through ground muon detectors data is make difficult due to the temperature effect. Furthermore, detector electronic changes or temporary problems may difficult the analysis of these variations. In this work, we analyze the cosmic ray intensity observed since October 1970 until December 2012 by the Nagoya muon detector. We show the results obtained after analyzing all discontinuities and gaps present in this data and removing changes not related to natural phenomena. We also show the results found using the mass weighted method for eliminate the influence of atmospheric temperature changes on muon intensity observed at ground. Furthermore, we show the preliminary results of the analysis of the solar cycle modulation on the muon intensity observed for more than 40 years.