Resources Created by the CSU Tropical Group

Forecasting and Research Resources

CSU Atlantic Multi-Decadal Oscillation (AMO) index

In 2008, Phil Klotzbach and Bill Gray published a paper in Journal of Climate discussing a newly-developed Atlantic Multi-Decadal Oscillation index that utilized a combination of two predictors: 1) Sea surface temperatures (SSTs) in the far North Atlantic from 50-60°N, 50-10°W and 2) sea level pressures (SLPs) in the North Atlantic from 0-50°N, 70-10°W. At present, the index is calculated by weighing the SST component as 60% of the index and the SLP component as the remaining 40%. All values are standardized using the 1981-2010 climatological average as a baseline. Real-time monthly values are calculated from the NCEP/NCAR Reanalysis and are typically updated by the 5th of the following month.

Monthly AMO values AMO_TC relationship

Standardized monthly values of the Klotzbach and Gray (2008) AMO index from 1950-present

All columns are sortable - click ()

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1950 -0.06 -0.12 0.09 0 0.94 0.59 0.65 0.16 -0.52 -0.35 0.32 -0.15
1951 -0.04 -0.06 0.71 0.74 1.03 1.8 0.92 0.16 0.7 0.13 0.04 -0.2
1952 -0.45 0.6 1.31 0.32 1.43 1.36 0.81 1.26 0.83 1.09 1.21 1.35
1953 0.98 0.96 0.73 1.65 1.93 0.45 0.19 0.05 0.32 -0.13 -0.42 0.14
1954 0.13 0.25 0.69 -0.4 0.87 0.47 0.42 0.83 -0.34 0.16 -0.04 -0.09
1955 1.29 0.77 1.12 1.17 1.12 1.18 0.82 0.6 -0.13 0.57 1.73 1.3
1956 1.29 1.13 1.02 1.39 -0.05 -0.48 0.39 0.1 0.22 -0.2 0.15 -0.03
1957 -0.2 0.48 1.33 0.43 0.84 1.06 0.98 0.36 0.92 0.23 0.42 -0.28
1958 0.69 1.4 1.68 0.67 0.71 1.4 1.4 1.21 1.11 -0.1 0.24 0.6
1959 0.83 0.18 0.19 0.56 0.9 0.53 -0.31 0.84 0.48 -0.03 -0.36 -0.11
1960 0.58 0.92 0.73 0.5 1.11 0.33 0.57 0.7 -0.2 0.88 0.45 -0.34
1961 -0.21 -0.13 0.24 1.34 0.33 -0.29 0.28 -0.23 -0.06 -0.59 0.38 0.94
1962 -0.33 -0.35 1.19 0.12 0.67 0.15 0.38 -0.38 -0.06 -0.06 -0.03 0.28
1963 0.76 0.75 0.45 1.53 -0.72 0.51 0.52 -0.38 -1.02 -0.24 0.25 0.17
1964 0.52 1.27 0.82 -0.37 0.57 0.85 -0.26 0.14 -0.31 -0.73 0.11 0.06
1965 0.47 0.8 1.02 0.57 1.13 0.26 -0.05 0.21 -0.2 0.16 -0.13 0.36
1966 1.52 1.6 0.79 1.55 -0.02 0.1 -0.07 0.71 0.68 0.82 -0.13 0.37
1967 0.67 0.62 -0.01 0.43 -0.21 -0.58 -0.67 -0.83 -0.43 -0.88 -0.44 -0.08
1968 -0.16 0.76 -0.25 0.2 -0.02 -0.1 -0.61 -0.24 -0.4 0.32 0.78 0.18
1969 0.71 0.98 1.08 -0.17 0.29 0.13 -0.63 -0.53 -1.07 -0.28 -0.59 -0.44
1970 0.95 -0.47 0.29 0.28 -0.38 -0.94 -0.88 -0.4 -0.34 -0.58 -0.41 -0.2
1971 0.55 -0.17 0.09 0.2 -0.19 -0.14 -0.11 -0.67 -0.43 -0.54 -0.62 -0.53
1972 -0.39 -0.58 -0.61 -0.45 -1.18 -1.62 -1.32 -1.23 -0.68 -0.79 -0.8 -1.1
1973 -0.94 -1.29 -0.69 -0.03 -0.46 -0.65 -0.89 -0.7 -0.57 -0.22 -0.04 -0.68
1974 -0.67 -0.56 -0.61 -1.05 -0.52 -0.36 -1.13 -1.05 -1.35 -1.64 -0.69 -1.04
1975 -0.92 -0.56 -0.63 -0.41 -0.04 -0.17 0.31 -0.09 -1.03 -0.62 -0.94 -0.48
1976 -0.54 -0.34 -0.58 -0.5 -0.98 -0.73 -0.86 -0.96 -0.53 -0.53 -0.92 -0.76
1977 -0.09 -0.08 0 -0.34 0.27 0.08 0.06 -0.2 -0.36 -0.47 -0.67 0
1978 -0.55 1.18 -0.01 0.47 -0.42 -1.18 0.02 -0.67 -0.38 -0.57 -1.03 0.5
1979 0.35 0.87 -0.33 0.17 0.29 -0.13 -0.9 -0.12 -0.28 0.04 -0.43 -0.3
1980 0.23 0.21 -0.04 0.11 1.11 -0.26 0.07 0.26 -0.93 -0.47 0.56 -0.27
1981 -0.23 -0.23 1.03 0.03 0.19 0.69 -0.1 -0.05 0.24 -0.72 0.14 0.72
1982 0.59 -0.11 -0.88 -0.66 -0.77 0.01 -0.53 -1.11 -1.34 -1.12 -1.75 -1.91
1983 -1.82 -0.92 -1.05 -0.99 -0.93 -0.65 -0.21 -1.13 -0.73 -1.54 0.13 -0.41
1984 -1.43 -1.42 -0.96 -0.29 -1 -0.97 0.18 -0.14 -0.11 -1.28 -0.76 -1.48
1985 -0.62 -0.76 -0.83 -0.7 -0.62 -0.67 -1 -1.39 -0.52 -0.89 -0.33 -0.4
1986 -1.18 -0.33 -1.51 -1.21 -1.06 -1.46 -1.26 -0.7 -0.03 -0.88 -2.07 -2.01
1987 -0.44 -0.29 -0.66 -0.73 -0.76 0.04 0.77 1.28 0.25 -1.06 -0.85 0.38
1988 -0.63 -0.65 -0.38 0.65 -0.13 -0.13 -0.87 -0.35 -0.35 -0.23 0.52 0.09
1989 -0.55 -1.18 -1.23 -1.35 -1.33 -0.51 -0.82 -0.1 -0.61 -0.75 -0.57 0.6
1990 -1.35 -1.29 -1.86 -2.05 -0.2 -1.14 -0.88 -1.25 -0.95 -0.47 -0.1 -0.73
1991 -1.6 -1.51 -0.46 -1.23 -0.99 -0.25 0.13 -1.02 -0.97 -1.16 -1.07 -0.87
1992 -0.36 -0.93 -1.19 -1 -1.2 -0.69 -0.54 -2.16 -2.04 -0.92 -1.06 -1.33
1993 -1.59 -1.6 -1.48 -1.18 -0.52 -0.68 -0.57 -0.96 -0.46 -0.41 -1.02 -1.56
1994 -1.59 -1.36 -1.46 -1.85 -1.09 -1.58 -1.72 -1.27 -0.84 0.55 0.22 -0.97
1995 -1.22 -1.33 -1.66 -0.56 0.39 0.46 1.33 1.07 -0.22 0.25 0.24 0.75
1996 0.81 -0.44 -0.38 0.43 0.28 -0.54 -1.07 -0.53 0.95 0.27 -0.33 0.42
1997 0.72 -0.48 -0.48 1.03 0.64 1.17 0.59 0.28 1.05 2.07 1.95 1.75
1998 0.45 0.46 0.05 0.3 0.22 0.82 0.86 0.7 1.77 0.76 0.43 0.14
1999 -0.47 -0.28 -0.09 0.12 0.09 -0.76 0.19 0.89 0.65 -0.21 -0.05 -0.19
2000 -0.36 -1.11 -0.05 -0.26 -0.28 -1.06 0.43 0.33 0.9 -0.79 0.27 0.31
2001 0.13 -0.08 0.66 -0.34 0.11 0.68 0.53 0.22 1.17 0.72 0.43 1.27
2002 0.75 -0.03 -0.4 -0.76 -0.89 -1.24 -1.46 -0.4 0.54 0.99 0.21 0.83
2003 0.55 -0.03 -0.12 0.13 -0.46 0.33 -0.35 0.07 0.53 1.22 1.13 0.84
2004 1.32 0.71 0.14 -0.09 -0.75 -0.35 -0.11 0.1 0.09 0.8 0.74 0.48
2005 -0.04 0.06 1.37 0.51 0.88 1.65 0.71 1.05 0.77 0.99 0.34 1
2006 0.72 0.77 1.01 0.43 0.71 0.02 0.34 1.21 1.8 1.97 1.14 0.05
2007 0.32 0.95 -0.14 0.65 -0.14 0.82 1.56 0.81 1.07 1.21 1.11 0.65
2008 0.08 -0.09 -0.3 0.2 1.22 1.07 0.69 1.43 0.34 -0.16 -0.15 0.06
2009 0.15 0.13 -0.02 -0.58 -1.31 0.17 0.58 0.06 -0.81 0.96 0.19 0.59
2010 0.53 1.69 0.65 1.08 1.34 1.3 1.17 1.7 2.61 1.97 1.81 2.33
2011 1.76 1.02 0.23 -0.25 -0.81 -0.59 -0.39 0.54 0.2 0.2 0.28 -1.04
2012 -0.81 -0.59 -0.65 -0.26 -0.07 1.5 1.96 1.67 0.99 1.69 0.58 0.67
2013 0.44 0.21 1.3 0.1 -1.09 -1.1 -0.26 0.28 0.44 1.55 0.3 -0.19
2014 -0.3 -0.55 -1.12 -0.94 -1.08 0.08 -0.26 1.15 0.67 0.56 -0.1 -1.2
2015 -1.56 -1.47 -1.88 -1.81 -2.24 -2.37 -0.76 -0.87 -0.26 -0.22 -0.57 -1.39
2016 -0.86 -1.72 -1.74 -1.64 -1.43 -0.32 -0.07 0.5 -0.16 0.25 0.17 -0.18
2017 -0.58 0.08 -0.61 -0.81 0.22 0.06 -0.89 0 0.31 0.16 0.39 0.33
2018 -0.61 -1.29 -0.5 -1.33 -2.03 -1.06 -2.01 -1.39 -0.81 -0.21 0.09 -0.2
2019 -0.48 -1.21 -1.87 -1.35 -0.34 -0.34 1.87 1.27 0.66 0.78 0.19 0.31
2020 -0.66 -1.3 -1.9 -0.75 -0.63 -0.85 -0.04 0.79 0.03 -0.42 -1.11 -0.97
2021 -0.14 -0.06 -0.76 0.25 -0.50 -1.17 -0.19 0.40 0.83 1.00 0.37 0.62
2022 -0.09 -0.81 -0.84 0.19 0.03 -0.07 0.00 0.63