Supplementary Material

Reconstructing El Niño Southern Oscillation using data from ships’ logbooks, 1815-1854. Part II: Comparisons with existing ENSO reconstructions and implications for reconstructing ENSO diversity

Authors: Hannah G Barrett1, Julie M Jones1 and Grant R Bigg1

1Department of Geography, University of Sheffield, UK

Corresponding author:

Hannah Barrett, Department of Geography, University of Sheffield, Winter Street, Sheffield, S10 2TN, UK

Email :

Fig. S1 Location of proxies used in ENSO reconstruction studies by ST98 (yellow triangles only), MANN00 (purple) and MCG10 (yellow, purple and red), with the exception of Cook et al. (2008) used in MCG10 as specific location data unavailable. Shapes indicate different types of proxy records (triangle = Tree-rings, circle = corals, star = ice cores, cross = instrumental).

Fig. S2 Location of proxies used in the ENSO reconstruction of W10, Tropical Teleconnection (TEL) ENSO reconstruction. Shapes indicate different types of proxy records (circle = corals, star = ice cores).

Fig. S3 Location of proxies used in ENSO reconstruction studies by EG13A (35 of these), EG13B (36) and EG13C (37). Shapes indicate different types of proxy records (triangle = Tree-rings, circle = corals, star = ice cores, square = sediment).

Fig. S4 The seven regions containing proxies used in the ENSO reconstruction by LI13. Number in parentheses indicates number of Tree rings in each region. Also shown is the weighting of the data from each region.

Table S1 Mean number of DJF logbook observations per grid box (1-9), 1815-1854 used in sub-sampled ERA-Interim data.

Grid box / 1 / 2 / 3 / 4 / 5 / 6 / 7 / 8 / 9
Average number of logbook wind observations (1815-1853) / 20 / 13 / 16 / 9 / 8 / 9 / 9 / 18 / 17

Table S2 Hit rates for El Niño and La Niña events from PCR and CPS fitting (full and 1. Iteration sub-sampled) compared to the instrumental DJF SOI.

El Niño Skill % / La Niña Skill %
PCR full fitting / 83 / 50
PCR sub-sampled fitting (1 it.) / 67 / 50
CPS full fitting / 67 / 50
CPS sub-sampled fitting (1 it.) / 83 / 33

Table S3 Hit rates of EP and CP events for the Instrumental DJF SOI, PCR fitting and CPS fitting (full and 1. Iteration sub-sampled) compared to the NINO method, 1979-2013.

DJF SOI / EP Skill (%) / CP Skill (%)
Instrumental / 100 / 33
PCR fitting / 100 / 66
PCR sub-sampled (1 it.) / 66 / 0
CPS fitting / 100 / 33
CPS sub-samples (1it.) / 100 / 66

Table S4 Location and labels of the nine predictor grid boxes used in the logbook reconstructions.

1 / 2 / 3 / 4 / 5 / 6 / 7 / 8 / 9
Latitude limits / 0oN 7.5oN / 30oS
37.5oS / 30oS
37.5oS / 30oS
37.5oS / 15oS
22.5oS / 15oS
22.5oS / 7.5oS
15oS / 7.5oS
15oS / 0oS 7.5oS
Longitude limits / 20oW 24oW / 12oE
20oE / 20oE
28oE / 36oE
44oE / 76oE
84oE / 84oE
92oE / 92oE
100oE / 100oE
108oE / 100oE
108oE

Fig. S5 DJF zonal wind anomalies (ms-1) during EP El Niño events 1982/83, 1991/92 and 1997/98 relative to 1979-2013 climatology. Predictor grid boxes used in the reconstruction are outlined in black.

Fig. S6 DJF zonal wind anomalies (ms-1) during CP El Niño events 1994/95, 2002/03 and 2009/10, relative to 1979-2013 climatology. Predictor grid boxes used in the reconstruction are outlined in black.

Fig. S7 DJF zonal wind anomalies (ms-1) during La Niña events 1988/89, 1998/99, 2007/08, 2008/092010/11 and 2011/12 relative to 1979-2013 climatology. Predictor grid boxes used in the reconstruction are outlined in black.

Table S5 Pearson’s correlation coefficients between the Instrumental SOI (DJF) and the Multi-Proxy ENSO reconstructions (year1 comparisons). All correlations are significant at the 99% level.

Correlation coefficients (1876-1977)
ST98 / 0.76
MANN00 / -0.73
MCG10 / -0.79
W10 / -0.48
EG13A / -0.79
EG13B / -0.82
EG13C / -0.80
LI13 / -0.65

Table S6 Correlation between the normalised ENSO proxies 1876-1977. Bold highlights those which are significant at 95% and non-SOI reconstructions are inverted to match the SOI

ST98 / MANN00 / MGC10 / W10 / EG13A / EG13B / EG13C / LI13
ST98 / --
MANN00 / 0.77 / --
MGC10 / 0.89 / 0.89 / --
W10 / 0.44 / 0.55 / 0.56 / --
EG13A / 0.69 / 0.74 / 0.78 / 0.52 / --
EG13B / 0.72 / 0.76 / 0.81 / 0.55 / 0.97 / --
EG13C / 0.73 / 0.76 / 0.83 / 0.53 / 0.95 / 0.95 / --
LI13 / 0.65 / 0.62 / 0.73 / 0.39 / 0.77 / 0.76 / 0.81 / --

Table S7 Correlation between the normalised ENSO proxies 1816-1854. Bold highlights those which are significant at 95% and non-SOI reconstructions are inverted to match the SOI

ST98 / MANN00 / MGC10 / W10 / EG13A / EG13B / EG13C / LI13
ST98 / --
MANN00 / 0.49 / --
MGC10 / 0.74 / 0.77 / --
W10 / 0.22 / 0.09 / 0.17 / --
EG13A / 0.27 / 0.49 / 0.55 / 0.03 / --
EG13A / 0.22 / 0.49 / 0.54 / 0.08 / 0.80 / --
EG13C / 0.29 / 0.49 / 0.53 / 0.15 / 0.94 / 0.86 / --
LI13 / 0.56 / 0.25 / 0.50 / 0.41 / 0.27 / 0.25 / 0.26 / --

Fig. S8 Zonal wind anomalies (ms-1) in 1818/19 and 1819/20, relative to 1815/16 - 1833/34 DJF climatology.

Table S8 The Logbook-based DJF SOI Reconstructions, 1815/15 – 1853/54

PCR A / PCR B / CPS A / CPS B
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853 / 1.12
6.88
5.39
18.99
18.78
3.21
6.86
7.74
3.56
-9.31
19.90
17.97
18.57
19.87
NaN
-7.04
27.86
5.60
-0.37
1.72
-31.84
45.55
-15.12
-14.50
-9.65
-4.40
-5.66
-28.19
-8.90
NaN
-8.73
4.01
-26.34
9.57
-5.38
-3.57
-43.31
-2.72
3.12 / -7.62
-1.87
-3.36
10.24
10.04
-5.53
-1.88
-1.00
-5.18
-18.05
11.15
9.23
9.83
11.13
NaN
-15.78
19.12
-3.14
-9.11
10.24
-23.33
54.06
-6.61
-5.99
-1.14
4.11
2.85
-19.68
-0.38
NaN
-0.21
12.52
-17.82
18.09
3.14
4.94
-34.80
5.79
11.63 / -0.14
0.88
-0.01
1.85
1.49
0.56
-0.01
1.46
-0.12
-0.45
0.82
0.99
0.82
0.88
NaN
-0.54
0.47
0.41
-0.75
0.60
-1.02
2.13
1.02
-1.80
0.04
-0.35
-0.29
-1.15
-0.22
NaN
-1.15
0.19
-1.24
0.22
-0.83
-1.16
-2.16
-0.94
-0.48 / -0.58
0.38
-0.64
1.62
1.21
0.29
-0.59
1.16
-0.75
-1.11
0.34
0.61
0.43
0.74
NaN
-1.35
0.32
-0.04
-1.82
1.23
-0.60
2.80
1.40
-1.37
0.48
0.08
0.13
-0.73
0.15
NaN
-0.75
0.74
-0.80
0.69
-0.48
-0.78
-1.84
-0.49
-0.06

Table S9 The SOI from the 5-iterations of randomly sub-sampled reanalyses data using the PCR reconstruction method. Red indicates El Niño event and blue indicated La Niña event

Iteration no. 1 / Iteration no. 2 / Iteration no. 3 / Iteration no. 4 / Iteration no. 5 / Mean of 5
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013 / 5.86
1.30
2.69
-25.46
8.86
-18.52
8.29
-19.97
-2.14
6.19
-1.60
-2.24
-4.07
-11.64
5.94
-8.40
13.43
18.89
-16.38
9.81
8.01
-6.72
-12.04
-8.31
7.24
-12.36
0.62
-11.29
12.30
1.93
-5.77
24.94
14.54
1.35
14.71 / 0.85
-2.76
-1.13
-13.40
4.59
-13.12
12.45
-9.27
3.44
9.80
-8.63
5.12
-0.07
-8.91
9.62
-5.36
19.23
1.83
-9.87
17.05
10.55
0.67
1.58
-2.97
-3.82
-19.79
4.15
-4.96
-0.23
0.88
-10.95
16.16
-1.42
2.97
-4.25 / 2.10
3.65
-4.22
-19.49
0.46
-3.94
7.31
-15.70
-13.35
11.07
-13.67
2.64
-14.37
-9.23
5.00
3.83
-3.59
22.50
-9.56
6.74
21.05
5.18
16.11
-9.39
0.68
-8.85
3.21
-12.55
4.80
3.80
-6.90
29.77
11.06
-6.45
-9.68 / 8.45
3.99
5.43
-19.58
3.40
2.78
6.02
-7.11
-12.08
0.53
4.47
-1.49
-13.31
-8.25
5.04
-1.16
16.37
17.62
-3.99
6.51
13.69
15.64
-2.55
-17.66
1.81
-5.37
-0.70
-19.02
-12.98
-5.55
-6.87
26.20
3.11
-2.70
-0.68 / -11.55
-0.51
3.37
-19.15
18.90
7.36
-2.03
-13.37
-7.49
8.81
3.87
-2.74
-2.63
-6.37
-14.21
-6.46
-2.40
3.69
-5.84
7.20
13.96
2.22
-8.07
-9.47
2.74
-6.75
-2.54
-5.75
22.14
7.91
-23.27
23.47
16.00
6.62
2.35 / 1.14
1.13
1.23
-19.42
7.24
-5.09
6.41
-13.08
-6.32
7.28
-3.11
0.26
-6.89
-8.88
2.28
-3.51
8.61
12.91
-9.13
9.46
13.45
3.40
-0.99
-9.56
1.73
-10.63
0.95
-10.72
5.21
1.79
-10.75
24.11
8.66
0.36
0.49

Table S10 The SOI from the 5-iterations of randomly sub-sampled reanalyses data using the CPS method. Red indicates El Niño event and blue indicated La Niña event

Iteration no. 1 / Iteration no. 2 / Iteration no. 3 / Iteration no. 4 / Iteration no. 5 / Mean of 5
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013 / 0.55
0.75
1.13
-1.61
1.01
-0.36
0.21
-1.12
-0.70
-0.18
-0.45
-0.21
-1.35
-1.05
0.29
0.08
0.53
-0.14
-1.26
1.51
1.30
0.76
0.27
-1.22
-0.76
-0.23
0.01
-1.39
0.87
0.70
-1.31
3.03
0.56
0.02
-0.24 / -0.17
0.56
0.84
-1.75
0.20
0.70
-0.56
-1.50
-0.76
0.03
-0.59
0.01
-0.76
-1.45
0.06
0.26
0.55
1.58
-0.90
1.21
1.65
0.52
-0.94
0.42
-0.30
-0.52
0.05
-1.50
0.42
0.71
-1.53
2.84
-0.02
0.50
0.14 / 0.02
0.91
0.47
-1.60
0.15
-0.92
-0.08
-0.98
-0.63
0.22
-0.26
-0.39
-1.37
-0.92
0.03
0.71
0.71
0.52
-1.34
1.15
1.69
0.43
-0.83
0.10
-1.02
-0.56
0.10
-1.23
2.16
0.27
-0.81
2.80
0.48
-0.60
0.59 / 0.90
0.89
0.35
-1.56
0.53
0.10
-0.36
-1.29
-0.68
0.54
-0.74
-0.48
-0.91
-1.51
-0.30
0.29
0.44
0.86
-1.47
0.99
1.56
0.67
-0.14
-0.20
-0.61
-0.62
-0.80
-1.41
0.56
0.63
-1.25
2.96
0.88
0.61
0.58 / 0.37
0.57
1.09
-1.87
1.47
-0.32
-0.18
-1.06
-0.16
0.30
-0.45
0.25
-1.70
-1.20
1.01
0.23
0.67
0.50
-1.17
0.89
1.41
0.49
-1.47
-0.67
-0.25
-0.74
0.01
-1.92
0.50
0.73
-0.46
2.54
0.49
0.06
0.03 / 0.33
0.74
0.78
-1.68
0.67
-0.16
-0.19
-1.19
-0.59
0.18
-0.50
-0.16
-1.22
-1.22
0.22
0.31
0.58
0.66
-1.23
1.15
1.52
0.57
-0.62
-0.31
-0.59
-0.53
-0.13
-1.49
0.90
0.61
-1.07
2.83
0.48
0.12
0.22

1