JISAO data
Northeast Brazil rainfall anomaly index, 1849-2002

Analyses | Digital values
The northeast Brazil rainfall index is calculated from data for Fortaleza (3.7S, 38.5W) and Quixeramobim (5.3S, 39.3W) Brazil obtained from the NCAR World Monthly Surface Station Climatology.

Climatolgy information also provided in the table below.
PostScript | JPEG
Climatological mean rainfall (in 0.1 mm) for Fortaleza and Quixerabmobim (1950-79):
              Jan  Feb  Mar  Apr  May  Jun  Jul  Aug  Sep  Oct  Nov  Dec
Fortaleza    1109 1690 3019 3403 2434 1280  778  239  206  132  189  348
Quixeramobim  648 1037 1683 1705 1265  612  374   86   23   21   64  169
Standard deviation of monthly rainfall (in 0.1 mm) for Fortaleza and Quixerabmobim (1950-79):
              Jan  Feb  Mar  Apr  May  Jun  Jul  Aug  Sep  Oct  Nov  Dec
Fortaleza     860 1439 1364 1372 1405 1003  823  341  198  109  276  425
Quixeramobim  612 1164  844  746  645  695  413  120   34   35  144  260
Domain shown is northern South America and the equatorial Atlantic
JPEG
Fortaleza and Quixeramobim (indicated as "F" and "Q" on the map of annual total rainfall, respectively) are located on the southern margin of the land monsoon and oceanic ITCZ rainfall region. Fortaleza is on the coast and Quixeramobim is located several 100 kilometers inland. The above map is calculated from 2.5-degree latitude-longitude resolution data.

To calculate the index, both the Fortaleza and Quixeramobim time series are standardized by calendar month with respect to the period 1950-79. This calculation removes the seasonal cycle of the mean and standard deviation for each series. The standardized series are then averaged together, and standardized again. This series is called the Fortaleza Quixeramobim index (FQI). Northeast Brazil rainfall is most commonly discussed in terms of the average conditions during the wet season, February through May. February through May (FMAM) averages are employed in the following figures, and the FMAM-averages are standardized with respect to the period 1950-79.
February through May averages of the FQI:

Historical record: 1849-2002
Image described below.
PostScript | JPEG
The series exhibits both year to year and decadal variability.

Modern record: 1950-2002:
Image described below.
PostScript | JPEG
The 1950s were dry, and the years beginning in 1997 have been near-normal or dry.
February through May averages of Fortaleza precipitation (cm/month) 1950-2002
Image described below.
PostScript | JPEG | PNG
Typical wet season rainfall of ~ 20 cm/month, and ranging from ~10 to >40 cm/month in dry and wet years, respectively.
Digital values
ASCII files:
  • Monthly values in column format. The columns are year, month, Fortaleza (0.1mm), Quixeramobim (0.1mm), and FQI. NaN for missing.
  • Monthly values as tables: Fortaleza, Quixeramobim, and FQI
  • FQI FMAM-averages column format and table format.
    FMAM-averages * 100
            +0    1    2    3    4    5    6    7    8    9
 1840                                               121
 1850 -140  130   -5  -36   17   32  106   97  -19  -30
 1860   68  -84   41   -5  -43  -97  305 -119  -75   54
 1870   83  -59  131  108    2   68   73 -240 -186 -186
 1880   41  -14  -77   55  -51    4   17   20 -168 -151
 1890   69  -62  -81  -51  215  202  144   97 -109  143
 1900 -188   -4 -138 -180  -99  -81   58 -162 -153  -69
 1910  155  -95  161  102  -25 -203  -18  133  -67 -226
 1920   65  175  132  -13  173   -2   64   18  -60   -1
 1930 -129  -77 -168  -69  171   42  -10  -30   45   58
 1940   72  -92 -150 -101  -19   41  -19   67  -13   76
 1950   35 -164   11  -98 -100  -32  -96    4 -190  -28
 1960   -3   69  -40   97  199   -1  -24  166  -41   68
 1970  -66    8 -108  201  197   20    3   11   -1  -95
 1980  -35  -24  -68 -145  136  165  194  -61   44   52
 1990 -102   39  -67 -186   68  137   31  -13 -190   -4
 2000    9  -78   35                                   


    
Monthly values * 100
    

           jan  feb  mar  apr  may  jun  jul  aug  sep  oct  nov  dec
 1849  -27  -11  -71  303  118  202   44  -13 -110  -98  -64  -90
 1850  -76  -32 -199  -76  -83    3  -32  -79  -52 -134  -87  -33
 1851  -79  255  -63   60  111  -35  -24  -69 -122 -134  -41  106
 1852  -38   35   23  -76    5   13  -92  -79 -122  -98  -69  106
 1853 -125 -112    7   43  -38   34  -57   17  -29   -2  -27   10
 1854 -119   20 -167   69  126  299  -51  -73  -99 -110  -78  -90
 1855 -138  -91  118  227 -164 -117  -78  -79 -110  -38  -69  137
 1856   11  152   12  248 -115  -95  -72  -46  -35  202   52  167
 1857  -67   82  -39  147   82  127  -72  -79  -64  -98  -78  -93
 1858 -125  -18 -210   15  159  -47  -61  203  285  -14  144  261
 1859  -82   54  -49 -114   26  127  -40   14  -52  -14  -83 -105
 1860  -94  105  -17    5   98   15   49   20  -70   46  -87  110
 1861  278  -53 -104   34 -111  -51  -99  -46  -64 -110  -36  584
 1862  -49   96   82 -102   39  -11  -96  -10 -104  -50   24  -93
 1863  -99   31 -111   92  -27  153  -47  -23  -64  -98   15  -42
 1864  -95   52 -115   27  -85  -79  -27  -10 -104  -86  -60  -87
 1865  -82  -48 -175  -90   44   82  -27   34  227  933  -32  -90
 1866 -113  -28  285  254  339  143  -61  -79  -87  285   28  -54
 1867 -125  -82  -42 -146  -62    0  -92  -30  -81 -158  -78  -81
 1868   96   -9  -63  -29 -109    9  -63   70   24  214  -74   -5
 1869  -73  142   40 -123   90  -79  -40   14 -122   82  -78  -87
 1870  -11   -8  155   59   26  -38 -103  -79  -93  369  -69   34
 1871  -99 -103   10  -39  -32  -55  213   17   76  190  -78  424
 1872   47  194  217 -120   75  147   72   37  169  -26  -83  164
 1873  246   90  104   74   35   38 -105  -79 -110 -146  357   76
 1874  -95   68   47 -104   -5  100  -38   17  -29   -2  -27   10
 1875 -138    5   70   27   88  -52  -31  -79  -70 -134  344   58
 1876  -58  -21   98  -43  169  -47  -32  -56 -104  154   15 -102
 1877 -108 -117 -179 -260 -114  -48  -46   73   -6 -158  -50 -105
 1878  -89  -68 -168 -241  -41 -134  -69  -79 -122 -134  -87 -105
 1879  -57  -93 -107 -219 -103 -110 -105  -30  -58  190  -18  -69
 1880 -119 -108  -89  269   41  -25   69   14   53  -26  -41   28
 1881 -118  -47  -98   60   46   36  138   73  -99 -158  -87  -57
 1882   -6 -106 -113  -20   23   70   64  -36  -64 -158  -87  -60
 1883  130   21   70  175 -113  -79 -105  -79  -99 -122  -78 -105
 1884  -98 -113   38  -15  -54  -93  -96    4  -52   58   52  -69
 1885 -138  -78 -112  226  -24  -50    6  -69  163  106  -60  -57
 1886   63  -61  180  -55  -17  -72  -95    7  -87  -98  -32  -75
 1887   35  -73  116  104  -90  -88 -101  -16 -116 -122  -87 -105
 1888  -67  -51 -155 -125 -138  -18  -32  -23 -122 -122  -87  -72
 1889  -89  -48  -70 -240  -62   -3 -105  -56  -35   34  -87  -15
 1890  -36  -24  158   -9   68 -109  -21  -50  -52  -50  -74   16
 1891  -33  -93 -121  -26   68  -82  -63   43  -87 -110   19 -105
 1892 -125  -47 -174   86  -91  -11  -57  -10   18   46  -69  539
 1893  241   47  -24 -131  -34  -75  -88  -43  -17   34  -60  224
 1894  278  102   90  418   -8  147  -72  -69  -87   34  218  -42
 1895 -109   -7  248  111  212  146  253  133   70  202  204  -72
 1896  -49  -41  210  149   82  -55   12  217  341  -40  -34  -89
 1897  -22   65   50   11  146   77   50   78  -14    6   -7  -88
 1898 -114  -12 -159  -85  -49  -90 -100  -74  -81  -99  -61  109
 1899   -9  228  226   73 -128   60   80  424  -66  -63  -57  -80
 1900  -33  -44 -192 -256  -32  -70  -53  -37  -90 -105  -72  636
 1901  -83   56   76  -81  -61  -32    9  -67   93  242   -7  -84
 1902  -31  -88 -114 -113  -71  -92  -38   32  -69   -3  -57  -59
 1903   64  -48  -99 -194 -163  -83  -78  -77  -64 -105  -58  -71
 1904  -88  -48   18 -163  -84  -50    1  221  -17  -46  -71  -73
 1905  -78  -61  105 -146 -125  -76  -92  -34  120   56  -65  -81
 1906 -109   73  -27   -6  122  -34  -82  -48  -90  -64  -61  -84
 1907  -71   -2 -143 -148 -158  -66  -46   67  -52  118  -50  -93
 1908  -73  -62 -101 -120 -146  -76  -35   -9  -64  150  -36  -82
 1909  -69   33 -182  123 -166 -109 -103  -66 -100 -117  -26  138
 1910   82   60  146   48  179  -69  -75  -80  -96  -10   41  397
 1911  143  -45   67 -165 -122 -100    5   92  -55  -34  -72   40
 1912   77  207  130   66   47   47  -75   25   26  -81  -68  -91
 1913  -34  233   48   -8   11   11  -46   15   20  -14  -38   84
 1914  121    2  -66    2   -6   47    0  508  -69  173  -47  -89
 1915 -101  -46 -188 -157 -174  -95 -103  -64  -93 -117  -58   87
 1916   -8  -41   79  -39  -49   78 -102  -71  -84 -117    9  326
 1917  451   56  116   79  121   -7  -64  -44  -15 -114  163  179
 1918    2    2  -77 -131   18   -6  -27  270  148 -117  -40  -21
 1919   26  -86 -169 -213 -163  -72  -30   43   78  -87  -44  -87
 1920 -110  -75  116   83   57  -15   29  -66  197  176    8  152
 1921   15  240   68   11  170  -36  135  -68   66  -66  343  -46
 1922  -78  -82   38  296  117   30  193   69  -17 -105  181  -40
 1923  -70  118  -35    4 -123  -30   -8  -69  -64  -78  -53  -81
 1924  -30   78  234  129   43  114  -74   56   -3   68   -9  100
 1925   82   20   27   20  -74  -86  -77  -46   10  -38  -10  -71
 1926  -37   56   92   51  -20  -49  -75  -80 -101   30  -32  -88
 1927  -61  -19  -22  149  -57  -57  -26  -77  -81  -66  -30  -26
 1928  -34  -82   65  -64  -87  -55  -95  -75  -20   76  -49  -58
 1929  -72   90  -50  -54   12  -32  -35  -73  -61   78  -33    4
 1930    9  -53  -94  -38 -176   -4  -48  -66  -90   58  -62  -15
 1931   -4   41  -39  -74 -145  -60  -74  -23   68   -1  -63  -31
 1932   -8    6 -131 -173 -171  -49  -69  -21  347  -54  -67  -65
 1933   16  -39  -53   42 -141 -102  -73  -64  -78  -22  -11  -47
 1934   62   90  287   -8  108  -19 -102  -55   17  -87   85  188
 1935   50   95  -18  101  -61    4  -45  -31   -5  -41  -51  -48
 1936  -88   41   -5 -182  117   33  -39  -71  -58  -75  -54  -66
 1937 -121   29 -134  -38   59   31    1    4   67   16  -35  -58
 1938  -13  -78  159  124  -79    9  -76  -44  -55  -52   30  -63
 1939  -77  163   78  -49  -28  -39  -16  -57  447  395  160  -86
 1940  -18  -14   34   98   83   44  -47   42   49    2  -60  -37
 1941 -113   -9  -32  -76 -138  -70   -7    6  -96  -90  -55  -56
 1942  -96  -54  -95 -133 -138  -92  -94  -12 -101   61  -40  133
 1943  -78  -51  -55  -78  -99  -66  -40  191  437 -111  -11    2
 1944  -23  -72   52   46  -80  -65  -34  -45  -88  -81  -64   76
 1945   72  113  -93    8   86   43   71  -26  -51  -50   -1  -23
 1946  155   76  -47   41 -123  -31  -90  -65  -46  636  -65  191
 1947  -37    9  130   43    5  -66  -65  -76  138  -73  354  226
 1948  -92  -80   99  -46   -9   48  -36  -11   37   18  -65  -87
 1949 -103  -29   53    5  181   45  -79  102  138  -93  210  -88
 1950  -30  -38   82   81  -26 -106  -74  -34  -18  -45  -18  -63
 1951 -105  -94 -203  -42 -121   85  -74  -80 -101  -98  109   88
 1952  -60  -54  111   20  -46  -96  -84  -37  -87   -8  -59  -30
 1953  -80  -73 -119   13  -96  -31  -95  -31  -20  -33  -63  -75
 1954  -63   -7  -77 -142  -54  -46  -93  -60  -81  -92  -43  -82
 1955    7  -44  -74   28    1  -87  -83  -23   -9  131  -33   57
 1956  -87   13  -22 -102 -158  -87  -46  163  -69  -68  -47  -72
 1957   -9  -95   83  122 -100  -95  -72  -35   -5    9  -68  -44
 1958 -101  -93 -188 -217  -32  -56  -12  -45    2  -93  -54  -70
 1959   78   -6   33  -92  -14  -38  -98  -36  -32  -50  -45  -63
 1960 -115  -99  152   -9  -52  -62  -46  -66  -67   22  -63  -38
 1961   62  142    6    2   42  -73   33  -80  -55  -87  -49   11
 1962  -66  -42   25  -37  -60  -32  -32  -29    7  -74  -18  154
 1963   78   68  207  132 -138  -56  -91  -59  -84 -104   60  329
 1964  253  166  120  161  109  -14   37  108  208  -26  -60  -68
 1965   29 -110  -70  139   36  252  -45  -34  -62  -23  -65  -70
 1966 -100  -10  -81    8   15   12   91  -54   28 -105    3  -23
 1967  -89  143   76   82  164    0   40  -22   30  -11  -60  -34
 1968  216  -55  -15  -86   41  -82   16  106  -82  142  -15  -16
 1969   27  -69  155    6   97   45  156   13  -45    2  -69  -88
 1970   40  -56  -31   66 -165  -63  -73  -14  -89  -52   83  -47
 1971   76    8  -18  -70  102  108  177   20   59   62  -29  -46
 1972  -65  -64 -103  -85  -48   50  -26  443  -87  -69  -63  207
 1973  -10  345   15  157   45   89  267    7  105  220   -1  -63
 1974  216   38   65  159  288   48  -36   -7  320  280   11  113
 1975   26  -25   58  -25   49  156  163  -18   -9    4  -42  114
 1976  -81   75   10  -15  -62  -74  -77  -43   16   29   30  -63
 1977   88  -24   -9   -3   67  292  131  -21  -81   14   21   78
 1978  -64  103 -110  -98  101  -15  122  -45  169  188  373  -13
 1979  -71  -47  -79 -156   15  -24  -74   12  139  -63  274  -79
 1980   23  203   35 -165 -171   16  -62  -26  -34 -117  -21  -46
 1981   -4  -48  326 -194 -152  -89 -102  -70 -101 -117  -61  995
 1982  -18  -27  -90  -43  -31  -54  -59   84  -43  148  732  -50
 1983 -107   24  -70 -204 -155  -71  -71  -52        21  -72    4
 1984  -12  -10   38  214  138  111   68   68   86  128  -65  -73
 1985  134  130   94  272  -34   40  156   76   28  -25  -35  395
 1986  -19  101  113  250   77  116  -40  228  658   41   79   35
 1987  -73  -26   50  -18 -176  112  -40  -67  -46  -20  -70  -22
 1988   72  -16   88   -6   57   67   12  -60  -14    4   28  212
 1989   50  -87    2   94  138  105  179   83  -81   74  -54  334
 1990  -88  -22 -172  -20       -36   23  -30   88   14  -23   34
 1991   65  -29  187   -2  -46  -78  -92  699  -72  238  191  -91
 1992  -46   58  -42  -55 -149  -13  -77  -13  -75  -69  -56  -85
 1993  -74  -48 -130 -191 -151  -60   21  -27    6  -56  -60  -70
 1994   31   45   95    2       302  -23  -72  -53       -37     
 1995  -64        30  194   63        11  -79 -101        95  -67
 1996   84  -90   63  106    7  -93  -71  140  -66   57    5  -57
 1997  -72  -57  -18   82  -43 -100  -78   96  293  -44   32   37
 1998   60  -76      -189       -85  -77   13  -87  -64  -67     
 1999   41   -4        -6    0  -70  -69  -70   78   11    9   85
 2000   92  -28  -12  112  -47    3   49  440  733 -122  -27   -9
 2001    0   14  -18 -120  -94   97  -25  -79  -87  -26    5   12
 2002  408  -47  -15  198  -39
    April 2003
    The old version of this index, which incorporated satellite data, is linked here. The old version will not be updated.
    Todd Mitchell (mitchell@atmos.washington.edu)
    JISAO data