LAUSR

Abstract It is considered that changes of the North Atlantic’s heat content can be a source of surprises in the evolution of the present-day climate, especially the climate of Europe. To investigate this problem, the RAPID monitoring program has been organized. However, results of such monitoring still cover too short a time interval to reach any particular conclusions. In this study, using wavelets, heat content variations in the 0–700 and 0–2000 m oceanic layers were analyzed since the mid-20th century. Their relationships with mean temperature variations of the 0–100 m layer, as well as with earlier analyzed temperature variations of the North Atlantic sea-surface temperature, also are analyzed. It is found that, against a total increase in heat content, variations of all specified characteristics reveal a periodicity similar to the known approximately 22‑year-long Hale heliomagnetic activity cycle. In the 0–700 m layer, this periodicity leading on its phase not only the corresponding periodicity in the 0–2000 m layer, which corresponds well to the generally accepted opinion that heat content anomalies extend from top ocean layers down, but also in the mean temperature of the 0–100 m layer, as well as in the sea-surface temperature. This makes it possible to consider that heliomagnetic activity immediately influences the upper 0–700 m layer of the ocean, thence extending down and up.