1899 - June 2001
Analyses | Digital values
Analyses | Digital values
The averaging region is based on the rotated principal component analysis of average June through September African rainfall in Janowiak (1988). Stations within 8-4N, 20W-10E are obtained from the National Center for Atmospheric Research World Monthly Surface Station Climatology, and 5 retained which had complete or almost complete records for 1950-93. [I created this index in 1996. As of 2001 there are more than 30 stations in the WMSSC with long records that could be used in this index. For this update, I used only the original 5 stations.] The stations are:
WMO* name location annual total (cm)
653380 BOHICON (7.2N, 2.1E) 113
653440 COTONOU, Benin (6.4N, 2.4E) 130
653760 ATAKPAME Togo (7.6N, 1.1E) 135
653870 LOME Togo (6.2N, 1.3E) 89
656600 ROBERTS FIELD (6.2N,10.3W) 339
* World Meteorological Organization number
The individual time series are standardized with respect to the calendar month mean and standard deviation for 1950-93. The index value for each year and month is taken as the mean of the available stations. The final index is standardized by calendar month with respect to the entire record, 1899-1993.
The following two analyses compare the precipitation in the Sahel and Gulf of Guinea. The plots were constructed with the NOAA Climate Prediction Center Precipitation Reconstruction data, which over land is rain gauge measurements.
Additional information on African rainfall variability can be obtained from the papers by Sharon Nicholson.
Reference:
Janowiak, J. E., 1988: An investigation of interannual rainfall
variability in Africa. J. Climate, 1, 240-255.
Digital values:
The rainfall index is provided in 3 formats:
jan feb mar apr may jun jul aug sep oct nov dec
1899 54 21 -62 192 22 -115 133 17 130 1 -133 -90
1900 82 32 -158 27 -37 -8 73 -42 -49 4 56 -84
1901 -105 40 19 -40 11 -132 -85 36 149 78 7 -75
1902 -36 243 -130 84 163 25 -85 -82 -56 -36 -110 -38
1903 43 61 -178 -41 -120 -88 -35 -88 -57 28 -56 -97
1904 -96 -95 -34 -50 20 19 -88 -85 -66 -122 -70 181
1905 -105 43 -94 -52 3 47 62 4 -182 -67 -27 -11
1906 -31 -38 -163 -18 199 -114 -76 -71 -134 -73 -30 144
1907 -63 48 -82 132 -93 194 -60 -38 -1 -74 -35 34
1908 192 -121 -21 163 -14 -128 -111 -101 261 91 114 -13
1909 380 99 91 -21 -84 11 -54 13 -32 -58 -49 449
1910 -101 -73 -86 21 -19 80 160 206 -24 183 291 -3
1911 331 -95 436 144 243 262 -24 -90 -64 -48 136 104
1912 86 -131 -96 -62 -101 104 -31 -71 -95 -109 -4 -95
1913 42 281 -89 -43 -62 5 436 21 58 -86 10 32
1914 104 -9 46 -2 -27 156 -19 46 -145 -170 125 -55
1915
1916
1917
1918
1919
1920
1921 105 -102 -3 142 25 124 -35 -97
1922 -34 240 -93 -153 -126 40 -93 -65 -52 76 73 -116
1923 61 -94 20 158 -117 -28 84 -70 -67 -33 -164 -134
1924 73 -26 -8 132 -181 -130 -73 -49 105 374 -164 144
1925 -101 -109 83 -82 127 106 -45 147 -37 -91 101 -71
1926 -98 52 10 100 29 -21 -61 -61 29 -78 88 -107
1927 58 97 -83 14 -176 -46 -112 -109 -61 40 15 19
1928 60 -41 -18 24 -73 -203 -64 -52 -29 61 -139 35
1929 25 -29 -32 -32 4 189 -16 -8 -28 -45 134 85
1930 -57 -138 67 -24 97 27 -44 -77 -98 54 -67 -95
1931 51 -13 -44 -20 8 -12 -85 11 -24 -97 98 168
1932 24 79 121 -73 143 -13 -153 -71 -73 -118 34 -64
1933 269 157 126 -40 206 18 123 36 -37 132 289 124
1934 -101 -118 47 -14 47 -70 60 95 72 185 29 295
1935 -7 40 39 -14 127 99 -27 51 -77 -128 7 99
1936 3 -53 34 -75 2 9 -25 -90 27 -35 19 -24
1937 -93 32 -36 -80 -129 -126 -80 -40 -12 86 -5 107
1938 -46 -44 18 115 -36 -59 -102 -51 3 -32 102 84
1939 87 39 191 37 -57 14 27 33 -84 -172 104 133
1940 -47 -68 -19 42 91 59 -5 -56 -83 47 -7 -53
1941 42 -85 7 -125 62 -109 -30 -8 66 68 15 -68
1942 191 -40 -37 -33 210 12 -123 -94 -13 7 -26 34
1943 151 -73 -49 -20 -37 54 -72 -52 -89 32 118 -14
1944 40 108 142 -61 -10 -69 0 24 -68 35 -118 -3
1945 -77 -58 52 -145 -188 -145 55 -38 96 93 52 -91
1946 234 109 232 223 37 -10 13 -98 -36 40 55 -57
1947 -53 82 47 15 56 -165 213 207 245 115 -70 15
1948 -101 -44 -46 88 105 -38 -123 39 -64 -66 103 -96
1949 15 36 -28 -117 74 18 149 150 72 50 173 -95
1950 78 -15 -133 -16 -27 62 -50 -89 -75 -63 89 -38
1951 50 -50 48 -128 -15 -67 32 -41 21 211 -58 -96
1952 79 119 95 -158 -3 82 -13 -60 179 61 152 -13
1953 -88 243 7 -35 73 78 75 -61 -19 77 54 -4
1954 9 42 104 -56 -34 23 -110 -101 -62 189 80 -63
1955 127 -35 150 39 -44 82 49 21 77 211 -126 -1
1956 -93 -15 288 -21 -83 -63 -112 -141 1 5 67 77
1957 53 -116 32 13 84 47 110 134 101 35 103 106
1958 68 65 -62 32 42 -63 -176 -135 -64 -8 89 -13
1959 9 139 98 145 129 -6 104 -103 -3 58 156 46
1960 2 -9 -29 167 -35 146 -19 36 143 157 -15 -2
1961 56 -92 22 43 -48 134 38 -103 -11 -15 9 -103
1962 -26 -41 16 -7 111 388 129 66 -134 -18 175 -55
1963 -55 117 33 -17 113 67 184 191 214 123 -38 -95
1964 -25 -63 -51 23 -15 29 -29 -53 -124 -124 -82 90
1965 135 -4 -39 143 -39 42 145 14 -39 -43 -67 -97
1966 -11 -118 -41 -7 -66 56 -26 16 -10 -46 7 94
1967 -90 -43 14 140 -36 95 -11 -20 36 -74 48 54
1968 -8 56 -3 27 -1 60 280 381 240 129 17 21
1969 -51 -60 85 -2 -40 -43 24 44 -10 19 -105 -104
1970 -32 -60 34 -33 143 -19 -82 73 24 18 -37 -104
1971 -12 123 5 -106 -69 32 -7 12 71 -147 -64 81
1972 -53 117 13 166 -53 65 -40 -36 -69 -64 -97 6
1973 -87 -92 69 -152 -88 -33 16 112 130 11 -139 36
1974 16 -83 4 -136 -36 49 45 4 117 -87 -114 -59
1975 -96 41 -34 98 -60 -115 124 -49 -72 -45 15 109
1976 -60 175 41 -15 -207 -79 -107 -83 -87 17 -16 116
1977 -55 -131 -138 -125 -121 -51 -120 -45 25 -146 -107 -60
1978 -22 34 117 155 116 20 -44 -94 -163 -73 65 -20
1979 -74 -148 -119 69 185 71 101 221 36 55 66 48
1980 -79 44 -124 -131 -144 -99 7 119 -120 -25 14 -73
1981 -87 -88 -106 -141 -4 49 -76 -59 -19 -46 -115 -90
1982 -47 188 -23 83 63 16 -84 -67 -92 -22 -29 -70
1983 -100 -151 -155 -136 114 48 -90 -124 -43 -213 -83 165
1984 -83 -113 39 -38 -11 -167 -17 32 -62 -59 -115 -81
1985 -23 -73 -44 -32 18 -100 31 101 24 -77 -7 -119
1986 -99 46 1 -80 -107 -107 -13 -79 -62 -19 -108 -113
1987 -93 -66 -36 -220 -110 -64 -71 311 373 18 -177 -45
1988 -78 -36 30 -27 7 49 65 10 125 -21 -22 50
1989 -100 -132 -38 -84 -30 112 60 149 -65 100 -136 -86
1990 -55 -42 -163 77 -183 -88 19 -29 17 -63 -30 36
1991 -58 35 -71 300 77 -165 143 60 -5 -72 -184 -5
1992 -96 -148 -103 -100 80 -45 -46 -101 72 -124 -147 -84
1993 -88 93 22 4 -143 -148 -22 47 -16 -60 -27 24
1994 -65 30 -35 -7 -58 -128 -64 -19 14 136 -5 -120
1995 -3 -127 113 83 -44 -44 -45 173 72 -123 -48 -4
1996 -87 81 17 -50 0 23 112 7 -88 -77 -146 -34
1997 -28 -131 28 -22 31 93 -6 -2 -19 138 287 284
1998 672 -48 -171 -60 12 -59 -49 13 -16 -20 -53 -100
1999 44 135 -55 24 -44 -49 436 233 35 39 -33 -44
2000 -139 -64 -114 -148 -88 33 68 42 -61 -153 -88
2001 -74 -143 -104 64 -59