Relationship of temperature changes in the mesopause region with the climate changes at the surface from observations in 1960-2024

TL;DR

This study analyzes long-term temperature variations in the mesopause region from 1960 to 2024, revealing a strong correlation with surface climate changes, including global warming and El Niño events, using wavelet analysis of hydroxyl airglow data.

Contribution

It provides the first observational evidence of long-term coherence between mesopause and surface temperatures over an extended period, supporting model predictions about climate-mesopause interactions.

Findings

Significant decrease in mesopause temperature over recent decades.

Strong coherence between mesopause and surface temperatures in the Northern Hemisphere.

Enhanced correlation between mesopause temperature variations and El Niño indices in recent decades.

Abstract

The results of an analysis of temperature variations in the mesopause region based on long-term measurements of hydroxyl airglow at the Zvenigorod Scientific Station of the A.M. Obukhov Institute of Atmospheric Physics RAS (ZSS IAP RAS) in 1960-2024 in comparison with variations of surface temperature characterizing global-scale climate changes are presented. Along with temperature variations in the mesopause region, two versions of temperature variations in the mesopause region, normalized to the same level of solar activity, were analyzed. Quantitative estimates of a strong decrease in temperature in the mesopause region over the past decades in winter against the background of a global increase in surface temperature have been obtained. It was noted that significant coherence of long-term variations for temperature in the mesopause region with the surface temperature in the Northern Hemisphere with the use of cross-wavelet analysis, what was not previously evident in data for a shorter time interval. The possibility of such coherence was predicted in (Mokhov et al., 2017) under the continuation of global warming based on the results of model simulations for the 20-21 centuries, taking into account anthropogenic forcing. It was not previously manifested from observational data for a shorter time interval. Along with long-term trends, features of a sharp decrease in temperature in the mesopause region in the 1970s with its synchronicity with the known shift in surface climate regimes associated with El Ni\~no events were analyzed. The results of cross-wavelet analysis using data obtained at the ZSS IAP RAS for the time interval 1960-2024 indicate a more significant connection between temperature variations in the mesopause region and El Nino indices in recent decades.