The Relationship between Snow Cover and Sea Ice Extent and Temperature Changes in the Northern Hemisphere Based on Data for Recent Decades.

Quantitative estimates of the relationship of the snow cover and sea ice extent in the Northern Hemisphere with surface air temperature in the annual cycle and interannual variability are obtained from modern satellite data and reanalysis data over the 1979–2020 period. The results indicate a general significant coherence and negative correlation between surface air temperature and the snow cover and sea ice extent not only in the annual cycle, but also for most months in the interannual variability. At the same time, specific features appear in the fall months, associated with regional features of the variability of temperature and the snow cover during the season of its formation in Eurasia and North America. For the winter months, an increase in the absolute value of parameters of the sensitivity of the snow cover and sea ice extent to temperature variations in recent decades and of the coefficients of their correlation is noted, while for the warm months, the opposite changes are observed. Along with a statistically significant negative correlation of the total snow cover and sea ice extent with variations in the hemispheric surface air temperature in the annual cycle, cross-wavelet analysis revealed a statistically significant negative correlation for the longest-term interdecadal variations with a manifestation in recent years of significant anticorrelation for interannual variations, in particular for variations with periods typical for El Niño events. [ABSTRACT FROM AUTHOR]