The correlation of 27 day period solar activity and daily maximum temperature in continental Australia

TL;DR

This study identifies a 27-day solar activity cycle in Australian temperatures, showing its correlation with solar radio flux near solar minimum and its localized, significant impact on temperature variations.

Contribution

First observation of a 27-day temperature cycle in Australia linked to solar activity, highlighting its phase variability and regional amplitude differences.

Findings

27-day temperature variation correlates with solar radio flux during solar minimum.

Amplitude of temperature response can reach up to 6°C.

Temperature response is localized and increases towards Australia's center.

Abstract

We report the first observation of a 27 day period component in daily maximum temperature recorded at widely spaced locations in Australia. The 27 day component, extracted by band pass filtering, is correlated with the variation of daily solar radio flux during years close to solar minimum. We demonstrate that the correlation is related to the emergence of regions of solar activity on the Sun separated, temporally, from the emergence of other active regions. In this situation, which occurs only near solar minimum, the observed 27 day variation of temperature can be in phase or out of phase with the 27 day variation of solar activity. During solar maximum correlation of temperature and solar activity is much less defined. The amplitude of the 27 day temperature response to solar activity is large, at times as high as 6 degrees C, and much larger than the well documented temperature response to the 11 year cycle of solar activity. We demonstrate that the 27 day temperature response is localised to the Australian continent and increases towards the centre of the continent. Several aspects of the 27 day temperature response are consistent with a 27 day period solar input to the Earth continents generating large scale planetary waves.