[Summary adopted from the online documentation at:
These temperature time series are derived from an update and expansion
of the corrected ...
This data set consists of two time series representative of Northern Hemisphere
growing season (April-September) temperatures for the period 1400-1994. The
data were derived from means of 383 maximum ...
Periods of widespread warmth or cold are identified by positive or negative
deviations that are synchronous across a number of temperature-sensitive proxy
records drawn from the Northern ...