Table 1. Comparison of the reconstructions with previous works.

Init date	End date	RSMD Casty	RMSD Luterbacher
1669	1680		0.90
1680	1700		0.72
1700	1720		0.31
1720	1740		0.78
1740	1760		0.69
1760*	1780	0.51	0.53
1780	1800	0.49	0.57
1800	1820	0.31	0.55
1820	1840	0.37	0.54
1840	1860	0.32	0.67
1860	1880	0.54	0.75
1880	1900	0.43	0.96
1900	1920	0.32	0.45
1920	1940	0.43	0.61
1940	1960	0.26	0.50
1960	1980	0.26	0.23
1980	2000	0.58	0.40
correlation	Before 1850	0.00	−0.15
correlation	After 1850	0.36	0.22

*The time-slice 1760–1780 for Casty starts in fact in 1766.

Square-root of mean squared discrepancies (RMSD) between the 20-yr mean maps of this paper and the 20-yr mean maps of [19] and between the 20-yr mean maps of this paper and the 20-yr mean maps of [20]. The last two rows present the correlation between our mean time-series and those of Casty and Luterbacher on respectively the common years before 1850 and after.