I am not aware of any study summarizing the strength of the global mean radiative restoring of low frequency variations in control simulations in the CMIP3 / AR4 archive. (gfdl.noaa.gov)
As mentioned earlier in our background section, tree ring proxies are typically calibrated to remove low frequency variations. (deepclimate.org)
The Collinge team's results, Bertranpetit and his coworkers argue, had been statistically skewed because its study left low frequency variations out of the analysis, an error known as «ascertainment bias.» (sciencemag.org)