PDO-ENSO years

Below are tables that categorize past winters according to the phase of the ENSO and PDO. Table 1 shows the breakdown of ENSO/PDO winters assuming the PDO pattern is truly regime-like, with continuous epochs switching phase in 1925, 1947, and 1977. Table 2 shows the breakdown when we use November-March values of our PDO index to identify the phase of the PDO for individual winters.

Data series used in the construction of this table are:

Note: the year listed includes the fall of the year prior and winter of the listed year (e.g., "2005" refers to the fall of 2004 and winter 2005)



 

Table 1: Extreme ENSO winters identified as those years for which the Dec-Feb NINO3.4 exceeds 0.5 standard deviations, or about 0.47 degrees C. For this table, the PDO phases are taken to be the continuous epochs listed in the first row.

Negative PDO: 1900-1924, 1947-1976, 1999-2002
Positive PDO: 1925-1946, 1977-1998, 2003-2005*
La Niña 1904 1907 1909 1910 1911 1917 1918 1921 1923 1950 1951 1955 1956 1963 1965 1968 1971 1972 1974 1975 1976 1999 2000 2001 1925 1932 1934 1938 1939 1943 1944 1945 1984 1985 1986 1989 1996 
ENSO Neutral 1901 1902 1908 1913 1916 1922 1947 1948 1949 1953 1954 1957 1960 1961 1962 1967 2002 1927 1928 1929 1933 1935 1936 1937 1946 1979 1981 1982 1990 1991 1993 1994 1997 2004
El Niño 1900 1903 1905 1906 1912 1914 1915 1919 1920 1924 1952 1958 1959 1964 1966 1969 1970 1973 1926 1930 1931 1940 1941 1942 1977 1978 1980 1983 1987 1988 1992 1995 1998 2003 2005

* It is believed that the PDO shifted to cool phase in mid-1998, but a recent (mid-2002) shift back to warm phase PDO makes it difficult to determine at this time if the 1998 shift was a true shift to a cold phase.



Table 2: Winter seasons as characterized by objective measures of the PDO and ENSO. (Oct-Mar PDO > 0.5 standard deviations, Dec-Feb NINO3.4 > 0.5 standard deviations, which is about 0.47 degrees C).


PDO: negative
PDO: neutral
PDO: positive
La Niña 1917 1918 1950 1951 1956 1963 1965 1971 1972 1974 1976 1989 1999 2000 1904 1907 1910 1911 1921 1923 1925 1932 1934 1938 1943 1944 1945 1955 1968 1975 1996 2001 1909 1939 1984 1985 1986 
ENSO neutral 1946 1949 1954 1957 1962 1967 1990 1991  1901 1916 1928 1929 1933 1947 1948 1953 1961 1979 1982 1993 1997 2002 1902 1908 1913 1922 1927 1935 1936 1937 1960 1981 1994 2004
El Niño 1952 1964 1966 1969 1995  1900 1903 1912 1915 1919 1920 1930 1958 1959 1973 1978 1992 2005 1905 1906 1914 1924 1926 1931 1940 1941 1942 1970 1977 1980 1983 1987 1988 1998 2003


Questions? send email to Nathan Mantua (mantua@atmos.washington.edu)

February 2, 2006