Table 1. Calibration and verification statistics indicate proxy/target agreement on all frequency domains.

	Full Calibration	Late Calibration	Early Calibration	Extra Calibration
	1860–2006	1934–2006	1860–1932	1816–1859
r	0.80	0.76	0.83	0.89
(low/high)	(0.76/0.81)	(0.70/0.78)	(0.89/0.84)	(0.96/0.88)
DW	1.55	2.10	1.42	1.73
	Extra Verification	Early Verification	Late Verification	Full Verification
RE	0.64	0.64	0.63	0.45
CE	0.61	0.39	0.38	0.41

Correlation coefficients of 12 proxy/target pairings, independently computed over different split periods and frequency domains, and for unfiltered and 20-year low- and high-pass filtered data range from 0.70–0.96 with a mean of 0.83 (p<0.001). Corresponding Durbin and Watson (DW) [48] statistics range from 1.42–2.10 (Table S3), and RE/CE statistics range from 0.45–0.64/0.38–0.61.