Table 2 Spearman's rank correlation coefficients between decadal (10 years) NAO_IP and other NAO proxy-based reconstructions employed to build up NAO indices.

NAO_IP

CE (200 BCE—Present)

0.18^d

0.51^a

0.20^b

0.22^b

0.40^a

0.08^d

0.13^d

0.07^d

RP (200 BCE–500 CE)

–

–

0.24^d

–

0.30^b

0.19^d

–

–

EMA (500–900 CE)

–

–

− 0.31^c

–

0.18^d

− 0.19^d

–

–

MCA (900–1300 CE)

–

0.28^d

0.30^d

0.84^a

0.57^a

− 0.05^d

0.50^d

− 0.26^d

LIA (1300–1850 CE)

− 0.22^d

0.29^b

0.27^d

0.06^d

0.35^a

− 0.33^b

0.13^d

0.10^d

IE (1850 CE—Present)

0.36^d

0.11^d

–

0.17^d

0.27^d

0.94^a

0.01^d

0.28^d