PDO INDEX

Updated standardized values for the PDO index, derived as the
leading PC of monthly SST anomalies in the North Pacific Ocean,
poleward of 20N. The monthly mean global average SST anomalies
are removed to separate this pattern of variability from any
"global warming" signal that may be present in the data.


For more details, see:

Zhang, Y., J.M. Wallace, D.S. Battisti, 1997:
ENSO-like interdecadal variability: 1900-93. J. Climate, 10, 1004-1020.

Mantua, N.J. and S.R. Hare, Y. Zhang, J.M. Wallace, and R.C. Francis,1997:
A Pacific interdecadal climate oscillation with impacts on salmon
production. Bulletin of the American Meteorological Society, 78,
pp. 1069-1079.
(available via the internet at url:
http://www.atmos.washington.edu/~mantua/abst.PDO.html)

Data sources for this index are:
UKMO Historical SST data set for 1900-81;
Reynold's Optimally Interpolated SST (V1) for January 1982-Dec 2001)
*** OI SST Version 2 (V2) beginning January 2002 -

missing value flag is -9999


YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

1900 0.04 1.32 0.49 0.35 0.77 0.65 0.95 0.14 -0.24 0.23 -0.44 1.19
1901 0.79 -0.12 0.35 0.61 -0.42 -0.05 -0.60 -1.20 -0.33 0.16 -0.60 -0.14
1902 0.82 1.58 0.48 1.37 1.09 0.52 1.58 1.57 0.44 0.70 0.16 -1.10
1903 0.86 -0.24 -0.22 -0.50 0.43 0.23 0.40 1.01 -0.24 0.18 0.08 -0.03
1904 0.63 -0.91 -0.71 -0.07 -0.22 -1.53 -1.58 -0.64 0.06 0.43 1.45 0.06
1905 0.73 0.91 1.31 1.59 -0.07 0.69 0.85 1.26 -0.03 -0.15 1.11 -0.50
1906 0.92 1.18 0.83 0.74 0.44 1.24 0.09 -0.53 -0.31 0.08 1.69 -0.54
1907 -0.30 -0.32 -0.19 -0.16 0.16 0.57 0.63 -0.96 -0.23 0.84 0.66 0.72
1908 1.36 1.02 0.67 0.23 0.23 0.41 0.60 -1.04 -0.16 -0.41 0.47 1.16
1909 0.23 1.01 0.54 0.24 -0.39 -0.64 -0.39 -0.68 -0.89 -0.02 -0.40 -0.01
1910 -0.25 -0.70 0.18 -0.37 -0.06 -0.28 0.03 -0.06 0.40 -0.66 0.02 0.84
1911 -1.11 0.00 -0.78 -0.73 0.17 0.02 0.48 0.43 0.29 0.20 -0.86 0.01
1912 -1.72 -0.23 -0.04 -0.38 -0.02 0.77 1.07 -0.84 0.94 0.56 0.74 0.98
1913 -0.03 0.34 0.06 -0.92 0.66 1.43 1.06 1.29 0.73 0.62 0.75 0.90
1914 0.34 -0.29 0.08 1.20 0.11 0.11 -0.21 0.11 -0.34 -0.11 0.03 0.89
1915 -0.41 0.14 -1.22 1.40 0.32 0.99 1.07 0.27 -0.05 -0.43 -0.12 0.17
1916 -0.64 -0.19 -0.11 0.35 0.42 -0.82 -0.78 -0.73 -0.77 -0.22 -0.68 -1.94
1917 -0.79 -0.84 -0.71 -0.34 0.82 -0.03 0.10 -0.22 -0.40 -1.75 -0.34 -0.60
1918 -1.13 -0.66 -1.15 -0.32 -0.33 0.07 0.98 -0.31 -0.59 0.61 0.34 0.86
1919 -1.07 1.31 -0.50 0.08 0.17 -0.71 -0.47 0.38 0.06 -0.42 -0.80 0.76
1920 -1.18 0.06 -0.78 -1.29 -0.97 -1.30 -0.90 -2.21 -1.28 -1.06 -0.26 0.29
1921 -0.66 -0.61 -0.01 -0.93 -0.42 0.40 -0.58 -0.69 -0.78 -0.23 1.92 1.42
1922 1.05 -0.85 0.08 0.43 -0.19 -1.04 -0.82 -0.93 -0.81 0.84 -0.60 0.48
1923 0.75 -0.04 0.49 0.99 -0.20 0.68 1.16 0.84 -0.24 1.10 0.62 -0.36
1924 1.29 0.73 1.13 -0.02 0.36 0.75 -0.55 -0.67 -0.48 -1.25 0.24 0.11
1925 -0.05 -0.14 0.20 0.86 0.79 -1.08 -0.06 -0.86 0.52 0.04 0.88 1.19
1926 0.30 0.98 -0.50 2.10 1.43 2.03 1.05 1.64 1.18 1.65 1.00 1.06
1927 1.07 1.73 0.15 -0.18 0.30 0.69 -0.31 -0.73 -0.41 -0.62 -0.07 0.07
1928 0.96 0.79 0.52 0.81 0.66 0.15 0.30 -0.72 -1.41 -1.31 0.14 0.98
1929 0.97 0.52 0.50 0.55 1.07 0.50 -0.06 -0.69 0.45 -0.21 1.24 -0.03
1930 0.97 -1.06 -0.43 -0.70 0.06 0.58 -0.45 -0.53 -0.20 -0.38 -0.31 1.20
1931 0.08 1.56 1.13 1.28 1.66 0.39 1.49 0.02 -0.01 -0.17 0.34 1.09
1932 -0.26 -0.58 0.51 1.15 0.64 0.10 -0.12 -0.14 -0.40 -0.29 -0.88 0.02
1933 0.29 0.02 0.15 -0.05 -0.50 -0.68 -1.81 -1.56 -2.28 -1.19 0.55 -1.10
1934 0.17 0.68 1.34 1.63 1.23 0.51 0.44 1.54 1.25 2.10 1.63 1.67
1935 1.01 0.79 -0.11 1.10 0.99 1.39 0.68 0.63 0.98 0.21 0.13 1.78
1936 1.79 1.75 1.36 1.32 1.83 2.37 2.57 1.71 0.04 2.10 2.65 1.28
1937 0.00 -0.49 0.38 0.20 0.53 1.75 0.11 -0.35 0.63 0.76 -0.18 0.55
1938 0.50 0.02 0.24 0.27 -0.25 -0.20 -0.21 -0.45 -0.01 0.07 0.48 1.40
1939 1.36 0.07 -0.39 0.45 0.98 1.04 -0.21 -0.74 -1.10 -1.31 -0.88 1.51
1940 2.03 1.74 1.89 2.37 2.32 2.43 2.12 1.40 1.10 1.19 0.68 1.96
1941 2.14 2.07 2.41 1.89 2.25 3.01 2.33 3.31 1.99 1.22 0.40 0.91
1942 1.01 0.79 0.29 0.79 0.84 1.19 0.12 0.44 0.68 0.54 -0.10 -1.00
1943 -0.18 0.02 0.26 1.08 0.43 0.68 -0.36 -0.90 -0.49 -0.04 0.29 0.58
1944 0.18 0.17 0.08 0.72 -0.35 -0.98 -0.40 -0.51 -0.56 -0.40 0.33 0.20
1945 -1.02 0.72 -0.42 -0.40 -0.07 0.56 1.02 0.18 -0.27 0.10 -1.94 -0.74
1946 -0.91 -0.32 -0.41 -0.78 0.50 -0.86 -0.84 -0.36 -0.22 -0.36 -1.48 -0.96
1947 -0.73 -0.29 1.17 0.70 0.37 1.36 0.16 0.30 0.58 0.85 -0.14 1.67
1948 -0.11 -0.74 -0.03 -1.33 -0.23 0.08 -0.92 -1.56 -1.74 -1.32 -0.89 -1.70
1949 -2.01 -3.60 -1.00 -0.53 -1.07 -0.70 -0.56 -1.30 -0.93 -1.41 -0.83 -0.80
1950 -2.13 -2.91 -1.13 -1.20 -2.23 -1.77 -2.93 -0.70 -2.14 -1.36 -2.46 -0.76
1951 -1.54 -1.06 -1.90 -0.36 -0.25 -1.09 0.70 -1.37 -0.08 -0.32 -0.28 -1.68
1952 -2.01 -0.46 -0.63 -1.05 -1.00 -1.43 -1.25 -0.60 -0.89 -0.35 -0.76 0.04
1953 -0.57 -0.07 -1.12 0.05 0.43 0.29 0.74 0.05 -0.63 -1.09 -0.03 0.07
1954 -1.32 -1.61 -0.52 -1.33 0.01 0.97 0.43 0.08 -0.94 0.52 0.72 -0.50
1955 0.20 -1.52 -1.26 -1.97 -1.21 -2.44 -2.35 -2.25 -1.95 -2.80 -3.08 -2.75
1956 -2.48 -2.74 -2.56 -2.17 -1.41 -1.70 -1.03 -1.16 -0.71 -2.30 -2.11 -1.28
1957 -1.82 -0.68 0.03 -0.58 0.57 1.76 0.72 0.51 1.59 1.50 -0.32 -0.55
1958 0.25 0.62 0.25 1.06 1.28 1.33 0.89 1.06 0.29 0.01 -0.18 0.86
1959 0.69 -0.43 -0.95 -0.02 0.23 0.44 -0.50 -0.62 -0.85 0.52 1.11 0.06
1960 0.30 0.52 -0.21 0.09 0.91 0.64 -0.27 -0.38 -0.94 0.09 -0.23 0.17
1961 1.18 0.43 0.09 0.34 -0.06 -0.61 -1.22 -1.13 -2.01 -2.28 -1.85 -2.69
1962 -1.29 -1.15 -1.42 -0.80 -1.22 -1.62 -1.46 -0.48 -1.58 -1.55 -0.37 -0.96
1963 -0.33 -0.16 -0.54 -0.41 -0.65 -0.88 -1.00 -1.03 0.45 -0.52 -2.08 -1.08
1964 0.01 -0.21 -0.87 -1.03 -1.91 -0.32 -0.51 -1.03 -0.68 -0.37 -0.80 -1.52
1965 -1.24 -1.16 0.04 0.62 -0.66 -0.80 -0.47 0.20 0.59 -0.36 -0.59 0.06
1966 -0.82 -0.03 -1.29 0.06 -0.53 0.16 0.26 -0.35 -0.33 -1.17 -1.15 -0.32
1967 -0.20 -0.18 -1.20 -0.89 -1.24 -1.16 -0.89 -1.24 -0.72 -0.64 -0.05 -0.40
1968 -0.95 -0.40 -0.31 -1.03 -0.53 -0.35 0.53 0.19 0.06 -0.34 -0.44 -1.27
1969 -1.26 -0.95 -0.50 -0.44 -0.20 0.89 0.10 -0.81 -0.66 1.12 0.15 1.38
1970 0.61 0.43 1.33 0.43 -0.49 0.06 -0.68 -1.63 -1.67 -1.39 -0.80 -0.97
1971 -1.90 -1.74 -1.68 -1.59 -1.55 -1.55 -2.20 -0.15 0.21 -0.22 -1.25 -1.87
1972 -1.99 -1.83 -2.09 -1.65 -1.57 -1.87 -0.83 0.25 0.17 0.11 0.57 -0.33
1973 -0.46 -0.61 -0.50 -0.69 -0.76 -0.97 -0.57 -1.14 -0.51 -0.87 -1.81 -0.76
1974 -1.22 -1.65 -0.90 -0.52 -0.28 -0.31 -0.08 0.27 0.44 -0.10 0.43 -0.12
1975 -0.84 -0.71 -0.51 -1.30 -1.02 -1.16 -0.40 -1.07 -1.23 -1.29 -2.08 -1.61
1976 -1.14 -1.85 -0.96 -0.89 -0.68 -0.67 0.61 1.28 0.82 1.11 1.25 1.22
1977 1.65 1.11 0.72 0.30 0.31 0.42 0.19 0.64 -0.55 -0.61 -0.72 -0.69
1978 0.34 1.45 1.34 1.29 0.90 0.15 -1.24 -0.56 -0.44 0.10 -0.07 -0.43
1979 -0.58 -1.33 0.30 0.89 1.09 0.17 0.84 0.52 1.00 1.06 0.48 -0.42
1980 -0.11 1.32 1.09 1.49 1.20 -0.22 0.23 0.51 0.10 1.35 0.37 -0.10
1981 0.59 1.46 0.99 1.45 1.75 1.69 0.84 0.18 0.42 0.18 0.80 0.67
1982 0.34 0.20 0.19 -0.19 -0.58 -0.78 0.58 0.39 0.84 0.37 -0.25 0.26
1983 0.56 1.14 2.11 1.87 1.80 2.36 3.51 1.85 0.91 0.96 1.02 1.69
1984 1.50 1.21 1.77 1.52 1.30 0.18 -0.18 -0.03 0.67 0.58 0.71 0.82
1985 1.27 0.94 0.57 0.19 0.00 0.18 1.07 0.81 0.44 0.29 -0.75 0.38
1986 1.12 1.61 2.18 1.55 1.16 0.89 1.38 0.22 0.22 1.00 1.77 1.77
1987 1.88 1.75 2.10 2.16 1.85 0.73 2.01 2.83 2.44 1.36 1.47 1.27
1988 0.93 1.24 1.42 0.94 1.20 0.74 0.64 0.19 -0.37 -0.10 -0.02 -0.43
1989 -0.95 -1.02 -0.83 -0.32 0.47 0.36 0.83 0.09 0.05 -0.12 -0.50 -0.21
1990 -0.30 -0.65 -0.62 0.27 0.44 0.44 0.27 0.11 0.38 -0.69 -1.69 -2.23
1991 -2.02 -1.19 -0.74 -1.01 -0.51 -1.47 -0.10 0.36 0.65 0.49 0.42 0.09
1992 0.05 0.31 0.67 0.75 1.54 1.26 1.90 1.44 0.83 0.93 0.93 0.53
1993 0.05 0.19 0.76 1.21 2.13 2.34 2.35 2.69 1.56 1.41 1.24 1.07
1994 1.21 0.59 0.80 1.05 1.23 0.46 0.06 -0.79 -1.36 -1.32 -1.96 -1.79
1995 -0.49 0.46 0.75 0.83 1.46 1.27 1.71 0.21 1.16 0.47 -0.28 0.16
1996 0.59 0.75 1.01 1.46 2.18 1.10 0.77 -0.14 0.24 -0.33 0.09 -0.03
1997 0.23 0.28 0.65 1.05 1.83 2.76 2.35 2.79 2.19 1.61 1.12 0.67
1998 0.83 1.56 2.01 1.27 0.70 0.40 -0.04 -0.22 -1.21 -1.39 -0.52 -0.44
1999 -0.32 -0.66 -0.33 -0.41 -0.68 -1.30 -0.66 -0.96 -1.53 -2.23 -2.05 -1.63
2000 -2.00 -0.83 0.29 0.35 -0.05 -0.44 -0.66 -1.19 -1.24 -1.30 -0.53 0.52
2001 .60 .29 0.45 -0.31 -0.30 -0.47 -1.31 -0.77 -1.37 -1.37 -1.26 -0.93
2002** 0.27 -0.64 -0.43 -0.32 -0.63 -0.35 -0.31 0.60 0.43 0.42 1.51 2.10
2003** 2.09 1.75 1.51 1.18 0.89 0.68 0.96 0.88 0.01 0.83 0.52 0.33
2004** 0.43 0.48 0.61 0.57 0.88 0.04 0.44 0.85 0.75 -0.11 -0.63 -0.17
2005** 0.44 0.81 1.36 1.03 1.86 1.17 0.66 0.25 -0.46 -1.32 -1.50 0.20
2006** 1.03 0.66 0.05 0.40 0.48 1.04 0.35 -0.65 -0.94 -0.05 -0.22 0.14
2007** 0.01 0.04 -0.36 0.16 -0.10 0.09 0.78 0.50 -0.36 -1.45 -1.08 -0.58
2008** -1.00 -0.77 -0.71

** Derived from OI.v2 SST fields
A graphic comparing monthly PDO values for 1982-2002 derived from the v1 and v2
sst products is available at
http://jisao.washington.edu/pdo/img/v1v2PDOComp.png


URL: ftp://ftp.atmos.washington.edu/mantua/pnw_impacts/INDICES/PDO.latest

and

http://jisao.washington.edu/pdo/PDO.latest

If you have any questions about this time series, contact
Nathan Mantua at: mantua@atmos.washington.edu