Reference: Jacoby and D'Arrigo, 1989; D'Arrigo and
Jacoby, 1992; 1993;
Proxy Type: tree-ring widths
Standardized climate record reflecting surface air temperature. Red indicates
temperatures greater than one standard deviation warmer than average for the reference
period (1901-1960), whereas dark blue indicates at least one standard deviation colder
than this average. All series presented as five-year averages (see paper for more
explanation).