Researchers have found that galactic cosmic rays influence both rainfall and temperature in India over periods of decades1. They detected a significant relationship between cosmic ray flux and the rainfall and temperature on some parts of the west and east coasts of India.
Galactic cosmic rays consist of charged particles that travel through space at nearly the speed of light. These particles bombard the Earth’s atmosphere and have been shown to influence rainfall on Earth. But it has yet to be proved whether cosmic rays affect ambient temperature, which in turn affects rainfall.
To investigate this question, the researchers analysed monthly cosmic ray fluxes (neutron counts per hour) recorded at the US-based National Geophysical Data Centre between the years 1953 and 2005. They also analysed temperature and rainfall data for India over the same period.
Cosmic ray fluxes were measured by dividing the study period into four cycles of 11 years each. The researchers found that the post-monsoon rainfall increases during high cosmic ray fluxes. With the exception of the second (1966–1977) and fourth (1988–1999) cycles, they observed a higher than usual minimum temperature during periods of high cosmic ray fluxes.
They also found a lower than usual maximum temperature during high cosmic ray fluxes in the first cycle (1956–1967), whereas the last cycle showed a higher than the usual maximum temperature during high cosmic ray fluxes. During periods of high cosmic ray fluxes, the spatial variability of rainfall at Tamil Nadu was higher. Also, high rainfall occurred near Andhra Pradesh during low cosmic ray fluxes.
