Direct observations of sunspot numbers are available for the past
four centuries, but longer time series are required, for example, ...
Recent reconstructions of northern hemisphere temperatures and climate
forcing over the last 1000 years allow the warming of the 20th century
to be placed within a historical context and various mechanisms ...
Reconstructed solar total and background irradiances.
11-yr Tootal Solar Irradiance (TSI) component since 1874 is from Foukal and
Lean: earlier from Hoyt Sunspot Groups
Background Brightness component ...