[Paper Review] Further investigations into the connection between cosmic rays and climate

A. Dragić, Nikola Veselinović+5 more|arXiv (Cornell University)|Apr 30, 2013

Solar and Space Plasma Dynamics14 references3 citations

TL;DR

This study investigates the relationship between cosmic ray variations—specifically Forbush decreases (FD) and sudden increases (GLE)—and deviations in the diurnal temperature range (DTR). Using statistical analysis of cosmic ray and climate data, it finds modest but consistent correlations with expected phase relationships and proportional responses, though confidence levels remain low, suggesting the need for more events to strengthen evidence.

ABSTRACT

Our previous results on the connection between the Forbush decreases (FD) of cosmic-ray intensity and the deviations from the expected values of the diurnal temperature range (DTR) are briefly revisited. The same type of analysis is then extended to the cases of sudden increases of cosmic-ray intensity (GLE), as well as to the search for lattitude effects in the observed correlations. We find that all the investigated correlations appear to manifest both the expected signs and the plausible phase relations, though each one only at the modest confidence level. Moreover, it appears that there is some proportionality between the magnitude of a cosmic-ray intensity change and a corresponding DTR deviation, both in the case of FD and GLE events. Eventual increase of the confidence levels at which these correlations are established would have to wait for the significant increase of the number of well defined and sufficiently intense recorded departures of cosmic-ray intensity from its stationary mean value. On the other hand, the probability of such an accidental multiple coincidence of independent pieces of evidence is certainly very low.

Motivation & Objective

• To re-express and extend prior findings on cosmic ray-induced diurnal temperature range (DTR) anomalies during Forbush decreases (FD).
• To investigate whether sudden increases in cosmic ray intensity (GLE events) also correlate with DTR deviations.
• To explore potential latitudinal variations in the strength or phase of cosmic ray–climate correlations.
• To assess the robustness and significance of observed correlations across different cosmic ray intensity events.
• To evaluate the likelihood of these correlations being due to random coincidence across multiple independent data points.

Proposed method

• Re-analyzed previously published data on Forbush decreases (FD) and their association with diurnal temperature range (DTR) deviations.
• Extended the analysis to include sudden increases in cosmic ray intensity (GLE events), treating them analogously to FD events.
• Applied statistical correlation techniques to detect phase-locked relationships between cosmic ray intensity changes and DTR anomalies.
• Examined spatial patterns by testing for latitude-dependent effects in the observed correlations.
• Assessed the confidence levels of detected correlations using statistical significance testing.
• Evaluated the proportionality between the magnitude of cosmic ray intensity changes and the corresponding DTR deviations.

Experimental results

Research questions

• RQ1 Do Forbush decreases in cosmic ray intensity correlate with measurable deviations in the diurnal temperature range (DTR)?
• RQ2 Do sudden increases in cosmic ray intensity (GLE events) also produce detectable DTR anomalies?
• RQ3 Are there significant latitudinal variations in the strength or phase of cosmic ray–DTR correlations?
• RQ4 Is there a proportional relationship between the magnitude of cosmic ray intensity change and the resulting DTR deviation?
• RQ5 What is the probability that the observed correlations are due to random coincidence across independent data points?

Key findings

• Correlations between Forbush decreases (FD) and DTR deviations show the expected signs and plausible phase relationships, though only at a modest confidence level.
• Sudden increases in cosmic ray intensity (GLE events) also exhibit correlations with DTR anomalies, showing similar expected signs and phase relations.
• A proportional relationship is observed between the magnitude of cosmic ray intensity change and the corresponding DTR deviation, in both FD and GLE cases.
• The probability of a random multiple coincidence of independent correlation signals is considered very low, suggesting potential physical relevance.
• The current statistical confidence levels remain low, indicating that stronger evidence would require a significant increase in the number of well-defined, intense cosmic ray departure events.
• Latitudinal effects were investigated but no definitive conclusions were drawn due to insufficient statistical power.