Table 1 Indices used in study and descriptions for index-reconstructions

Average surface land temperature and SST of the Northern Hemisphere

(Jones & Moberg 2003; Rayner et al. 2006)

SSTA averaged over 0 to 60°N, 75°W to 7.5°W

(Kerr 2000; Enfield et al. 2001; Sutton and Hodson 2003)

Normalized pressure (SLP) difference between the Azores High-Pressure system (~33.2°W, 32.2°N) and the Icelandic Low-Pressure system (~33.15°W, 59.6°N). [~1^st PC of SLP in North Atlantic]

(Hurrell 1995)

Average SSTA 5°N to 5°S, 170°W to 120°W

(Trenberth 1997)

2^nd EOF of SLPA from 100°E to 120°W, 0 to 90°N

(Wang et al. 2007)

Leading PC of SSTA north of 20°N in North Pacific; globally averaged SSTA subtracted from SSTA in Pacific to remove global-warming signal.

(Mantua et al. 1997)

Relative intensity of SLP in North Pacific around 50°N in winter (DJFM). The mean area in km^2 with SLP less than 100.5kPa. Expressed as anomaly relative to 1950 to 1997 mean.

(Beamish et al. 1997)