Contribution of Solar Irradiance Variations to Surface Air Temperature Trends at Different Latitudes Estimated from Long-term Data

Contributions of the insolation variations together with different natural and anthropogenic factors to the trends of the surface air temperatures at different latitudes of the Northern and Southern Hemispheres on various temporal horizons are estimated from climate data since the nineteenth century with the use of empirical autoregressive models. As the natural climate variability modes, we take into account Atlantic Multidecadal Oscillation, El-Nino/Southern Oscillation, Interdecadal Pacific Oscillation, Pacific Decadal Oscillation, and Antarctic Oscillation. According to the obtained results, the contributions of the insolation variations to the trends of the surface air temperature are statistically insignificant on the time intervals under study, i.e. from a decade and longer. Taking into account the insolation variations in the autoregressive models weakly alters the estimates of the contributions of the greenhouse gases and natural variability modes to the temperature trends: the changes are not more than several per cent. Numerically, the estimated contributions of the insolation variations can considerably exceed the respective contributions of the natural variability modes both on short (less than two decades) and long (longer than a century) time intervals.

Automated summary

Contributions of insolation variations to surface air temperature trends at different latitudes of Northern and Southern Hemispheres on various time scales were estimated using empirical autoregressive models. Results showed that the contributions of insolation variations to temperature trends were statistically insignificant during the studied time intervals. The inclusion of insolation variations weakly influenced the estimates of greenhouse gases and natural variability modes' contributions to temperature trends, with changes not exceeding several percent. Numerically, the estimated contributions of insolation variations could significantly exceed those of natural variability modes on both short-term (less than two decades) and long-term (over a century) time scales.