11-Year cyclicity of the near-surface heat flux at the Vostok station

It is known that the solar component is difficult to find in a climatic signal due to its small size and significant internal random disturbances of the climatic system, such as variations in cloudiness, precipitation, winds, and oceanic currents. In the center of the polar cap, these disturbances are as minimal as possible; therefore, solving the inverse heat conduction problem, we can calculate the informative heat flux through the ice cover based on temperature data. Variations in the heat flux are quite significant in amplitude (0.2–0.3 W/m²) and coincide with the 11-year solar cycle in phase. Application of this approach to the indices of the global and sea surface temperatures cannot yield a solar signal, yet it can be traced for solar cycles with big amplitude (cycles 19 and 21). Thus, the found variation in the heat flux is most probably caused by a change in the solar constant (TSI); however, other mechanisms are also possible.