Six Temperature Proxies of Scots Pine from the Interior of Northern Fennoscandia Combined in Three Frequency Ranges

Table 1

Six proxies versus mean July temperatures (average of the four records, no filtering) in 1908–2002. Reduction of error (RE), coefficient of efficiency (CE), and 𝑟² during EC-LV (early calibration in 1908–1955 and late verification in 1955–2002) and LC-EV (late calibration in 1955–2002 and early verification in 1908–1955). Only test results with RE and CE > 0 are included.

	EC-LV			LC-EV
	RE	CE	𝑟^2	RE	CE	𝑟^2
(A) RCS indexing
FXD	0.29	0.21	0.35	0.10	0.02	0.14
RRW	0.25	0.17	0.19	0.21	0.14	0.16
(B) 180-year spline indexing
SRW	0.30	0.22	0.29	0.24	0.18	0.32
SXD	0.26	0.18	0.25	0.15	0.08	0.12
FXD	0.35	0.28	0.36	0.14	0.07	0.15
RRW	0.27	0.19	0.21	0.23	0.17	0.18
(C) 30-year spline indexing
SRW	0.27	0.19	0.30	0.4	0.34	0.43
FRW	0.29	0.21	0.39	0.13	0.05	0.24
FHI	0.52	0.47	0.57	0.23	0.17	0.23
RRW	0.18	0.09	0.25	0.27	0.20	0.33