JISAO data
"G", the leading principal component of global sea surface temperature anomaly "deviations"
Analyses | Data

This WWW page is an update of the "G" timeseries defined in Zhang, Wallace, and Battisti (1997), and it is the leading PC of global SST anomaly deviations. The "deviations" are that the global mean temperature is removed for each month, and this is intended to remove the secular warming that dominates the variability in the dataset. The data set is a 4 by 6 degree latitude-longitude resolution version of the ICOADS sea surface temperature anomalies (I don't think that the dataset choice is important). A 3-month running mean is applied temporally to fill small gaps in the data. Grid boxes with >= 70% complete records were used in the EOF calculation (PS|PNG), and whatever missing values there were in those gridboxes were replaced with zeros. The leading EOF of the area-averaged covariance explains 8.5% of the variance.


Big GIF | PDF | PS | PNG

The following are the correlation and regression maps of "G". For reference I am also including the maps for the cold tongue index, plotted with the same conventions.

Big GIF | PDF | PS | PNG

Big GIF | PDF | PS | PNG


Big GIF | PDF | PS | PNG

Big GIF | PDF | PS | PNG


Big GIF | PDF+ | PS | PNG
The two time series are correlated at 0.88, and "G" has more low frequency variability to it than CTI (although that isn't clear visually).

Reference:
Zhang, Y., J. M. Wallace, and D. S. Battisti, 1997: ENSO-like interdecadal variability: 1900-93. J. Clim., 10, 1004-1020.
The time series are available as:
  • A 3-column table: year, calendar month, value
  • A 1-column table
  • A table of the values organized by year and month

    G * 100 
           jan  feb  mar  apr  may  jun  jul  aug  sep  oct  nov  dec
 1900   74   87   88  105   86  103   93   86   63   47   61   67
 1901   74   77   60   39   -5  -39  -35  -19   15   49   76   78
 1902   66   44   53   85  138  206  220  204  172  162  164  137
 1903  113   81   65   56   47   43   49   37   38   19   -1  -13
 1904  -21    4   -7   13   30   56   91  128  145  155  152  156
 1905  152  154  154  169  165  180  176  189  190  174  147  143
 1906  132  119   91   61   52   42   14  -10  -15  -18  -25  -29
 1907  -21  -36  -29  -37  -10    4   19   34   56   64   59   55
 1908   43   26    2  -37  -30  -39  -22  -25  -15  -18  -12  -14
 1909  -16  -30  -36  -54  -75 -101  -99 -122 -109 -120 -113 -116
 1910 -122 -121 -113 -119 -108 -103  -82  -64  -62  -75  -65  -53
 1911  -55  -70  -89  -62  -43  -10    5   18   56   87   91   87
 1912  106   96   94   58   52   24   24   46   59   49   14   11
 1913   35   38   11   -6    6   22   59   78   67   81   95  121
 1914  117  101   81   73   47   43   43   58   45   72   72   92
 1915   60   68   66   87  102   96   81   41   12  -40  -49  -55
 1916  -38  -33  -33  -43  -61  -99 -154 -170 -180 -179 -183 -176
 1917 -138 -109  -74  -89  -82  -64  -33  -32  -47  -74  -82  -61
 1918  -41  -23  -24  -17   13   38   83  105  125  120   96  103
 1919  101   82   49    9   11   -6   11   30   43   46   29   61
 1920   55   57    4    8  -22  -13  -34  -30  -38  -20  -15  -15
 1921  -40  -82 -117 -116  -82  -73  -71  -54  -62  -45  -30  -20
 1922  -19  -47  -48  -65  -69  -61  -69  -75  -85  -70  -69  -68
 1923  -70  -64  -31  -10    1   12   42   75   89   79   42   -1
 1924   -5  -23  -41  -62  -82 -109 -132 -134 -125 -121  -91 -101
 1925  -71  -61  -15  -18  -13   -4   45   72   88  125  138  161
 1926  148  171  180  178  136  108   65   58   22   27   20   28
 1927   20   -2  -27  -59  -57  -47  -47  -31  -10    4    7   26
 1928   32   34   25   14    2  -13  -23  -45  -55  -48  -27  -27
 1929  -35  -33  -23   -3    7   28   30   41   37   40   41   42
 1930   53   53   68   65   46   58   90  130  142  165  173  183
 1931  181  174  174  152  131  101   82   57   34    7   -2   -7
 1932  -21    6   30   64   71   65   51   15    9    7   -5  -33
 1933  -51  -49  -50  -73  -94 -120 -141 -145 -137 -127 -125 -113
 1934  -91  -73  -47  -37  -30  -35  -18   -9    0   -4  -12  -34
 1935  -55  -65  -40  -16   -8  -14  -22   -3    6    0    0   -9
 1936   11   16   38   58   61   44   20   17   32   38   36   -9
 1937  -16  -17   -2  -28  -25  -17  -10  -16  -19    3   12  -13
 1938  -35  -71  -87 -108 -123 -146 -149 -131 -100  -90  -85  -76
 1939  -56  -44  -35  -14   17   22   17    8   24   33   53  120
 1940  143  148  128  138  154  142  128  104  109  118  154  182
 1941  204  205  196  196  194  184  172  161  164  150  149  163
 1942  132   80   74   34   20  -35  -68  -98  -99 -117 -117 -112
 1943  -80  -63  -57  -17   -3   14    2  -29  -58  -84  -90  -72
 1944  -48  -45  -18  -13  -19  -40  -41  -47  -49  -55  -53  -44
 1945  -42  -64  -70  -67  -20  -41  -32  -34  -13  -22  -25  -38
 1946  -20    3  -10  -23  -20  -20  -24  -31  -20  -27  -28  -10
 1947   22   35   25    9   -5   -4  -17  -19  -29  -19  -16   -7
 1948    7    6    5    7  -15  -27  -38  -58  -76  -66  -67  -73
 1949  -84  -79  -62  -59  -53  -63  -64  -74 -100 -131 -138 -153
 1950 -172 -183 -168 -168 -166 -187 -167 -163 -136 -146 -152 -160
 1951 -145 -144 -118  -79  -29   25   40   54   58   80   64   21
 1952   -9  -18  -12  -22  -50  -73  -97  -78  -59  -55  -58  -37
 1953  -32  -12    6   22   38   30   23   40   18   29   -4  -24
 1954  -50  -57  -87 -108 -121 -105  -92 -121 -133 -142 -127 -105
 1955 -125 -146 -181 -193 -196 -191 -172 -185 -211 -249 -268 -247
 1956 -192 -160 -156 -143 -147 -142 -127 -117 -133 -148 -138 -119
 1957  -94  -41   16   69  103  129  143  146  139  142  145  154
 1958  169  160  151  135  137  128  107   73   48   49   59   74
 1959   64   62   51   44   31   15    0  -25  -20   -5    5    6
 1960  -10    1    2   14    4  -16  -35  -36  -41  -60  -56  -30
 1961   -1   -6  -15  -35  -26  -53  -51  -81  -95 -114 -121 -129
 1962 -131 -128 -117 -111 -109  -99  -79  -76  -90 -110 -111  -83
 1963  -62  -38  -27  -28  -27  -16    7   56   74   83   69   67
 1964   52   11  -36  -95 -128 -143 -134 -122 -123 -106  -99  -82
 1965  -60  -15   34   77  105  119  138  149  157  157  163  148
 1966  118   74   38    3  -10  -10   -2   -2  -10  -19  -30  -48
 1967  -58  -69  -67  -63  -49  -51  -78 -110 -124 -116 -109 -104
 1968 -102  -93  -93 -104  -94  -60  -19   -5    7   18   34   61
 1969   67   65   58   63   81   66   45   30   57   80   94   74
 1970   54   36   19   -1  -49  -89 -127 -147 -160 -160 -163 -191
 1971 -214 -227 -200 -179 -166 -166 -145 -127 -126 -146 -164 -151
 1972 -104  -59  -25    0   42   81  133  156  182  180  189  181
 1973  133   68   -4  -57  -96 -129 -152 -175 -189 -208 -230 -250
 1974 -250 -224 -179 -136 -108  -84  -83  -70  -89 -105 -126 -130
 1975 -128 -125 -121 -136 -146 -147 -148 -164 -190 -208 -225 -235
 1976 -199 -154 -115  -88  -33   34   82  102  116  127  136  144
 1977  124   90   37   20   27   53   59   56   63   75   81   82
 1978   77   75   54   30    2  -15  -31  -32   -7   31   39   32
 1979    6    4   13   44   59   56   47   66   82   94   90   85
 1980   82   77   85   96   91   79   53   39   33   37   45   32
 1981   14    6    9   20   18   17    8    5   12   14    5    0
 1982   -3   -8   -2   30   71  102  124  161  205  248  275  291
 1983  292  291  281  281  285  283  253  193  127   62   43   36
 1984   36   31   26   13  -19  -31  -29  -10   -9  -11  -30  -40
 1985  -57  -59  -76  -81  -76  -54  -24  -17  -23  -39  -46  -46
 1986  -22    1   20   15    9   25   41   64   84  120  148  157
 1987  159  170  184  192  179  180  185  205  214  212  192  144
 1988   86   45   19   -8  -57 -105 -131 -134 -141 -149 -154 -159
 1989 -149 -136 -112 -107  -98  -76  -67  -64  -70  -59  -23  -10
 1990   -1  -27  -20  -10   -1   -5   -6    3    2   -9  -23  -21
 1991  -10    1   -8    1    7   41   58   73   94  121  137  141
 1992  147  165  188  218  214  189  133   95   74   81   84   89
 1993  100  120  141  170  189  182  162  139  131  117   99   87
 1994   57   43   30   46   62   51   32   33   62   75   77   66
 1995   73   65   39   22   23   35   15   -2  -28  -38  -50  -51
 1996  -38  -19  -16   -9  -26  -31  -52  -50  -38  -32  -42  -52
 1997  -53  -14   28  106  177  235  290  323  343  349  342  343
 1998  318  289  238  187  117   74   15  -33  -86 -130 -164 -191
 1999 -191 -180 -187 -190 -202 -182 -170 -159 -161 -185 -203 -214
 2000 -193 -171 -136 -133 -119 -116 -110  -98  -93 -104 -112 -113
 2001 -103  -85  -80  -68  -77  -84  -78  -82  -86 -105 -109  -96
 2002  -80  -47  -38  -21  -27  -19   -9   11   36   74  114  108
 2003   98   69   47   -7  -36  -56  -35  -32   -8    5   23   26
 2004   10   -7  -25  -18   -8   -8   -8   10   23   34   35   38
 2005   21   20   11   39   35   26   -2  -35  -67 -114 -128 -128
    An earlier version of this calculation, which employed data only from 1950-onward, is linked here.

    June 2006
    Todd Mitchell (mitchell@atmos.washington.edu)
    JISAO data