The correlation between atmospheric temperature in Tibet and sunspot activity from 1978 to 2018

To investigate whether the temperature changes in Tibet are related to sunspot activity, we analyzed the monthly average temperature data from 1978-2018 at three sites in Tibet and the global monthly average sunspot number during the same period. We used various statistical methods such as linear fitting, sliding average, Mann-Kendall mutation test, and wavelet analysis. The key findings are summarized as follows: (1) Both the monthly average sunspot number and the monthly average temperature in Tibet exhibit cyclic patterns. (2) The average temperature during the hot months exceeds the annual mean temperature, which in turn is higher than the average temperature recorded during the cold months at all three sites. Furthermore, the centennial temperature variability in the cold season is greater than that observed in the warm season. (3) Mutation points are present at all sites, exhibiting a trending upwards albeit not significantly. (4) From 1978 to 2018, there is a single primary cycle that governs the characteristics of the monthly mean temperature in Tibet. This cycle is 18-month (1.5a) in duration and exhibits a moderate correlation with sunspot activity. (5) No significant correlation was identified between the monthly mean temperature and the monthly mean sunspot numbers at the three stations. The annual average temperature in the Tibet region does not exhibit a visually apparent relationship with sunspots across multiple time scales, instead, it demonstrates a dual effect of "lagging" and "accumulation" in relation to sunspot activity. (6) The incidence of extreme temperatures is potentially correlated with variations in the peak and trough sunspot numbers. Additionally, an inverse relationship may exist between the daily maximum and minimum temperatures and the sunspot numbers. Furthermore, A weak positive linear correlation is observed between the 11-year sliding average of sunspot numbers and temperature at Damxung, which may reflect the cumulative effect of solar radiation on the surface energy balance over decadal scales.