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Southern Hemisphere Annular Mode (SAM) Index

or Antarctic Oscillation (AAO) Index

The SAM Index Data


The SAM index (SAMI) or AAO index (AAOI) is defined as the difference in the normalized monthly zonal-mean sea level pressure (SLP) between 40¡ãS and 70¡ãS (Nan and Li, 2003). This SAMI is a modification of the AAO index defined by Gong and Wang (1999), which is the difference in the normalized zonal-mean SLP between 40¡ãS and 65¡ãS. The modified SAMI is used here because the negative correlation in the zonal-mean SLP anomalies between 40¡ãS and 70¡ãS is stronger than that between 40¡ãS and 65¡ãS.

The Southern Hemisphere Annular Mode (SAM) Index

The SAM index. Top. DJF (1947-2010); Middle. JJA (1948-2010); Bottom. Annual (1948-2010) 

The yellow lines indicate 7-year Gaussian-type filtered values.

Related References

Nan, S., and J. Li, 2003: The relationship between summer precipitation in the Yangtze River valley and the previous Southern Hemisphere Annular Mode. Geophys. Res. Lett., 30(24), 2266, doi: 10.1029/2003GL018381. Electronic version PDF

Li, J., 2005: Coupled air-sea oscillations and climate variations in China, in: Climate and Environmental Evolution in China (First Volume), Edt. D. Qin, Beijing: China Meteorological Press, 324-333. Electronic version PDF

Gong, D., and S. Wang, 1999: Definition of Antarctic Oscillation Index, Geophys. Res. Lett., 26: 459-462. Electronic version available through this link

Thompson, D. W. J., and J. M. Wallace, 2000: Annular modes in the extratropical circulation. Part I: Month-to-month variability. J. Climate, 13, 1000-1016. Electronic version available through this link


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The Southern Hemisphere Annular Mode Index Data

Filename

Size

Description

SAMI(AAOI)1948-2012.ASCII

7 kilobytes

SAM index (AAO index)

You can download this file from here (right-click then select "Save Target As" or "Save Link As").

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File format

for year = 1948 to 2012

     format (i4, 18f7.2) year, 12 * monthly value, DJF, MAM, JJA, SON, annual, and DJFM values

Note: (1) Missing values represented by -99.99;

         (2) The reference period is 1958-2000;

         (3)  DJFM / DJF SAM indices: The DJFM index value for year N refers to an average of December year N and January, February, and March year N+1 indices values (Example: The 1948 index value was based on the average of December 1948 and January, February, and March 1949 indices values).

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The SAM(AAO) Index from Nan & Li (2003, Geophys. Res. Lett., 30: 2266, doi:10.1029/2003GL018381). The value, -99.99, is undefined.
         1      2      3      4      5      6      7      8      9      10     11     12    DJF    MAM    JJA    SON    Ann   DJFM
1948  -0.46  -2.32  -1.70  -0.32   2.47  -0.77  -4.20  -4.56  -1.99  -3.08  -2.82  -1.51  -4.43   0.15  -3.18  -2.63  -1.77  -3.96
1949  -4.89  -6.89  -2.54   0.50   2.38   2.64  -1.14   0.17   0.21  -0.95  -1.02  -3.98  -3.52   0.11   0.56  -0.59  -1.29  -3.27
1950  -4.75  -1.84  -2.53  -1.26   0.15  -1.62  -3.03  -1.70  -0.60  -1.15  -2.10  -0.22  -0.12  -1.21  -2.12  -1.28  -1.72  -0.65
1951   0.46  -0.61  -2.23  -3.16  -2.54  -3.23  -1.72  -3.14  -3.30  -3.31  -2.31  -3.72  -2.85  -2.64  -2.70  -2.97  -2.40  -2.60
1952  -3.93  -0.90  -1.84  -1.88  -1.70  -1.19  -0.21  -1.19  -2.59  -1.20  -2.69  -2.88  -2.44  -1.81  -0.86  -2.16  -1.85  -2.19
1953  -2.61  -1.82  -1.46  -3.49  -2.14  -0.61  -2.80  -0.60  -1.19  -2.23  -0.80  -2.42  -0.47  -2.36  -1.34  -1.41  -1.85  -1.45
1954   0.97   0.05  -4.39  -0.80   0.67  -1.63  -1.31  -4.45   1.30   0.28   1.90  -2.11  -0.47  -1.51  -2.46   1.16  -0.79  -0.07
1955   0.37   0.34   1.10   0.55  -1.86  -1.75   2.10  -3.90  -1.25  -3.90  -2.89  -1.51  -1.61  -0.07  -1.18  -2.68  -1.05  -1.39
1956  -1.63  -1.68  -0.75  -0.70  -0.17   2.13  -2.33  -1.99  -3.03  -1.29  -2.25  -4.49  -2.41  -0.54  -0.73  -2.19  -1.51  -1.72
1957  -1.28  -1.46   0.34  -1.07  -1.05  -3.32  -1.19  -1.98   0.29  -3.34  -2.84  -2.76  -0.73  -0.59  -2.16  -1.96  -1.64  -0.88
1958   0.64  -0.06  -1.35  -1.51  -1.74   0.52  -2.21   0.24   2.75  -0.21   1.05   2.70   1.41  -1.53  -0.48   1.20   0.07   1.23
1959   1.87  -0.33   0.66  -1.61  -2.13  -2.10  -2.50  -2.41   0.47  -0.57   2.06   0.08   0.23  -1.03  -2.34   0.65  -0.54   0.64
1960   0.01   0.60   1.87  -1.67  -3.34   0.20  -0.28  -2.76  -0.68   0.12   0.44   0.27  -0.16  -1.05  -0.95  -0.04  -0.43  -0.34
1961   0.27  -1.01  -0.89   0.40  -0.40  -1.53  -1.42  -0.82  -1.39   0.08   1.21   3.31   1.78  -0.30  -1.26  -0.03  -0.18   1.20
1962   2.82  -0.78  -0.56   1.99  -0.42  -2.81   1.57  -0.32   0.34  -1.94  -2.10   1.82   2.07   0.34  -0.52  -1.23  -0.03   1.88
1963   2.58   1.82   1.30  -1.05  -0.14  -1.41  -1.51  -6.63  -1.78   0.81  -0.14   0.82  -0.86   0.04  -3.18  -0.37  -0.44  -0.81
1964  -2.14  -1.25  -0.68  -0.17   1.00  -4.55  -6.37  -3.14   0.52  -0.12  -1.97  -1.84  -2.27   0.05  -4.69  -0.52  -1.73  -2.06
1965   0.02  -4.98  -1.42  -1.72  -2.69   0.08  -1.99  -1.85  -1.61  -1.14   0.38  -2.26  -1.01  -1.94  -1.25  -0.79  -1.60  -1.70
1966   0.51  -1.29  -3.78  -1.18  -3.31   1.86  -0.87   0.86   0.39   1.19  -1.12  -0.56  -1.35  -2.76   0.62   0.15  -0.61  -0.87
1967  -2.73  -0.75   0.56   0.12  -0.45  -0.58   0.32   0.07  -0.14  -0.12  -1.14  -0.70  -0.73   0.08  -0.06  -0.47  -0.46  -0.50
1968  -0.36  -1.13   0.21  -2.37  -3.82   0.12   1.17  -0.76  -3.34  -2.15  -2.72  -1.22  -2.14  -1.99   0.18  -2.74  -1.36  -1.66
1969  -3.83  -1.38  -0.19  -1.09  -0.25  -0.14   0.26   1.02   0.84  -0.24   1.58   0.12   0.67  -0.51   0.38   0.73  -0.27   0.12
1970   1.17   0.73  -1.52  -0.88   0.44   0.81  -0.11   2.84   0.02  -2.16   0.56  -2.05  -0.82  -0.65   1.18  -0.53  -0.01  -0.43
1971  -0.94   0.53   0.76  -0.13  -1.90   0.66  -1.30   0.37   0.00  -1.58  -0.44  -1.84  -1.76  -0.42  -0.09  -0.67  -0.48  -1.57
1972  -2.60  -0.83  -1.02  -3.23   0.19  -1.95  -0.92  -2.83  -0.54   0.01   1.24  -2.18  -1.01  -1.35  -1.90   0.24  -1.22  -0.32
1973  -1.00   0.14   1.75  -0.13  -2.20   0.72   1.68   1.64  -0.80   0.65  -0.73   2.49   1.60  -0.19   1.35  -0.29   0.35   1.61
1974   0.08   2.24   1.63   0.59  -0.13  -0.06  -0.23  -3.67   2.10  -1.17  -1.86  -2.16  -1.29   0.70  -1.32  -0.31  -0.22  -0.89
1975  -1.75   0.05   0.30   0.27  -1.63  -0.83  -1.93   1.78   2.41   1.63  -0.20   0.22   0.21  -0.35  -0.33   1.28   0.03   0.25
1976  -0.57   0.97   0.39   1.91   1.66   0.51   0.81   0.49  -0.01  -1.20  -3.56  -7.13  -3.56   1.32   0.60  -1.59  -0.48  -2.94
1977  -3.25  -0.31  -1.07  -1.06  -0.43  -1.26  -0.65  -1.06   0.97   0.53   0.31  -0.83   0.42  -0.85  -0.99   0.60  -0.68   0.30
1978   1.52   0.56  -0.06  -0.20  -1.50   0.37  -3.51   3.62   1.43   0.17  -0.60   0.77   0.69  -0.59   0.16   0.33   0.21   0.88
1979   0.68   0.63   1.44   0.66   1.82   2.74   2.74   0.76   1.29   0.76  -0.98  -1.79  -1.35   1.31   2.08   0.36   0.90  -1.71
1980  -0.57  -1.68  -2.82  -3.12  -0.16   1.38  -2.86  -1.66  -3.04   0.91  -2.92  -1.50   0.32  -2.03  -1.05  -1.68  -1.50  -0.20
1981   1.43   1.04  -1.78  -2.46   0.49   1.21  -1.41  -2.98  -2.58  -1.18   2.15   3.27   1.18  -1.25  -1.06  -0.54  -0.23   1.72
1982  -0.72   1.00   3.34   3.03  -0.28   1.36  -0.32   1.46   1.92  -1.93   0.16  -2.89  -1.84   2.03   0.83   0.05   0.51  -1.13
1983  -2.02  -0.62   1.01   0.25   0.77   1.27   3.07   0.97  -1.39   2.60   2.76   0.95  -0.55   0.68   1.77   1.32   0.80  -0.39
1984  -1.88  -0.72   0.11   1.10   0.46   2.14   1.73  -0.28  -0.25  -0.13   1.01  -3.21  -1.36   0.56   1.20   0.21   0.01  -1.10
1985  -1.14   0.28  -0.35   1.48   0.52  -1.01   3.89   1.11   2.41   0.56   2.31   1.60  -0.04   0.55   1.33   1.76   0.97  -0.23
1986   0.97  -2.69  -0.82   0.55  -3.32   0.12  -0.28   0.19   1.41  -0.60   0.16   2.81  -0.03  -1.20   0.01   0.32  -0.13  -0.29
1987  -1.56  -1.35  -1.05   0.17   0.63  -0.21  -1.32   2.63  -1.52   0.64   2.28   0.59   0.45  -0.08   0.37   0.47  -0.01   0.32
1988  -0.62   1.39  -0.09   1.83  -0.41  -0.93   2.39   0.19  -0.84  -3.99   1.70   2.62   1.40   0.44   0.55  -1.04   0.27   1.43
1989   0.84   0.74   1.54   0.34   5.33   4.31   2.39  -0.62   0.16   0.68   1.43  -0.23   0.73   2.40   2.03   0.76   1.41   0.82
1990   0.45   1.97   1.09  -2.51  -1.09   0.88  -1.02   0.58   2.78   0.64   0.34   0.23   0.31  -0.84   0.15   1.25   0.36   0.31
1991   1.77  -1.07   0.30  -0.18   0.77  -0.59  -0.94   1.90  -2.06   0.18  -1.16  -3.16  -1.43   0.30   0.12  -1.01  -0.35  -1.52
1992   0.87  -1.99  -1.81  -0.58  -2.00  -2.86   0.31  -0.35  -0.25  -0.31  -0.11  -0.13  -1.08  -1.46  -0.97  -0.22  -0.77  -1.22
1993  -3.60   0.48  -1.61   0.39   2.90   2.81   4.06   1.10   1.72   1.14   0.60   1.88   1.68   0.56   2.66   1.15   0.99   1.34
1994   0.78   2.39   0.29   0.68  -0.21  -3.18   0.31   4.59  -1.87   0.17  -1.28   1.56   1.69   0.25   0.57  -0.99   0.35   1.20
1995   2.39   1.12  -0.28   1.49   3.55  -0.81  -3.14   0.11   2.92  -0.29   1.17   3.03   1.39   1.59  -1.28   1.27   0.94   1.29
1996   1.22  -0.08   0.98   1.03   2.55  -0.23  -0.17  -1.82  -2.69   2.50  -2.49   0.69   0.85   1.52  -0.74  -0.89   0.12   0.96
1997   1.70   0.16   1.27  -0.39   2.60   0.21   2.93   1.58   0.36  -0.38  -2.33  -0.19   1.24   1.16   1.57  -0.78   0.63   1.18
1998   2.06   1.86   1.00   4.26   0.50   3.03   5.16   3.99   1.69   0.94   2.48   2.74   2.22   1.92   4.06   1.70   2.48   1.83
1999   2.45   1.48   0.66   2.66   3.96  -1.25   1.63   0.44   0.71   3.75   2.40   3.80   2.70   2.43   0.27   2.29   1.89   2.19
2000   2.20   2.09   0.67   2.02   3.80   0.99   0.84  -0.58  -2.82   0.74  -1.92  -2.51  -0.93   2.16   0.42  -1.33   0.46  -0.61
2001   0.34  -0.61   0.35   2.73   1.10   2.52  -0.27   2.37   2.73   2.50   3.25   2.10   1.87   1.39   1.54   2.83   1.59   0.72
2002   1.78   1.74  -2.75   1.43  -2.48   0.92  -0.97  -0.41  -1.27  -4.88  -0.65   2.32   0.69  -1.27  -0.15  -2.27  -0.44   0.34
2003  -0.51   0.26  -0.71   1.28   2.95  -0.12   2.73   1.44  -0.23  -0.11  -0.67  -0.80  -0.06   1.17   1.35  -0.34   0.46   0.09
2004   2.33  -1.70   0.53   1.68   2.14   2.63   3.93  -0.13   1.16   0.11   0.14  -1.33   0.39   1.45   2.14   0.47   0.96   0.36
2005   0.85   1.65   0.28   2.26   1.16  -0.07   0.48   1.13   0.44   0.25  -0.56  -3.50  -1.12   1.23   0.51   0.04   0.36  -0.42
2006   0.91  -0.76   1.67   0.20   3.43   1.80   2.53  -2.15   0.71   2.17   1.27   1.13   0.85   1.77   0.73   1.38   1.08   0.48
2007   0.10   1.33  -0.62  -0.18   1.67   0.73  -3.06   1.40   0.21  -0.42   0.25   3.44   2.35   0.29  -0.31   0.01   0.40   2.08
2008   2.31   1.29   1.28  -0.10   0.26   4.24   0.58   2.06   2.49   2.73   2.45   1.86   1.54   0.48   2.29   2.56   1.79   1.31
2009   1.86   0.89   0.63   0.44   1.04   0.56  -0.49  -1.12   0.90   1.82  -1.28   1.96   0.39   0.70  -0.35   0.48   0.60   0.59
2010  -0.04  -0.74   1.16   1.74   3.34   5.34   5.75   2.85   2.31   3.34   3.54   1.62   1.42   2.08   4.65   3.06   2.52   1.13
2011   0.40   2.24   0.25   0.96   4.13   1.45   0.40  -0.79  -2.03   1.70  -0.32   4.31   2.08   1.78   0.35  -0.22   1.06 -99.99
2012   2.87  -0.95 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99

Last updated: 2012-03-05 (Jianping Li: ljp@lasg.iap.ac.cn)