The "Sun – climate " relationship. I. The sunspots and the climate.

Abstract. We investigate the problem about the reason for the significant sub-centurial (50-55 and 60-65 yr) and quasi-centurial (120-130 yr) climatic oscillations. The 50-55 and 60-65 yr cycles are clearly detectable in numerous global and regional climatic parameters, i.e. in the temperatures of the Northern Hemisphere and World Ocean surface, in the tree rings widths, in the atmosphere concentration of CO2, etc. Searching for analogues of these cycles in the solar activity we study the connections between various types of solar, geophysical and climatic cycles. In this Paper I we analyze time series of residual variations of the Northern Hemisphere (AD 1610-1979) and World Ocean surface (AD 1856-1995) temperatures in respect to the corresponding regression models "sunspot activity – temperature". We use the Group Sunspot Number (GSN) as sunspot activity proxy and confirm the existence of well pronounced 50-55, 60-67 and ≈118 yr cycles in the solar activity and temperature variations. In Paper II we will show the existence of powerful 60-65 yr cycle in the middle latitudes auroras and sub-centurial variations in the concentration of the Greenland and Antarctic "cosmogenic " 10Be. In Paper III we will summarize the evidences that the reason of these climatic oscillations are probably processes occurring in the solar corona. Unlike the overall solar activity and the total solar irradiance variations, the high level of these processes leads to a climate cooling, while their low levels correspond to climate warming