Averaging region: 4N-12S, 152.5E-82.5W
An analysis based of this index is linked here.
Details of the index calculation are given at the bottom of this page.
The time series written in MATLAB format. [The timeseries is read into the variable "eqpacprecip" in MATLAB.] The units are mm month-1.
A monthly-mean version of the time series written in MATLAB format. In this version, the seasonal-mean values are ascribed to the months which comprise the season. [The timeseries is read into the variable "eqpacprecip_monthly" in MATLAB.] The units are mm month-1.
The units in the following table are mm month-1, and there is no data value for September-October-November of 1989.
DJF MAM JJA SON
1892 -52 34 42 -133
1893 -34 -183 -127 -132
1894 -454 -297 -38 -158
1895 -89 -175 -189 71
1896 13 -17 137 253
1897 175 -135 -104 -36
1898 -227 -102 -132 -60
1899 -263 -131 257 98
1900 341 276 207 117
1901 37 58 -181 -164
1902 -245 79 322 401
1903 474 -9 -213 -162
1904 -426 -107 150 291
1905 295 348 267 388
1906 152 -172 -209 -16
1907 -151 -165 -126 95
1908 197 -175 7 -196
1909 -407 -264 -75 -137
1910 -457 -197 -136 -156
1911 -160 440 198 414
1912 497 453 -42 155
1913 298 -237 -82 194
1914 147 321 494 119
1915 202 412 -146 -206
1916 -274 -265 -227 -210
1917 -504 -257 -163 -139
1918 -442 -17 581 426
1919 478 366 306 438
1920 174 132 63 -189
1921 3 -139 -114 -81
1922 184 33 78 -101
1923 -202 8 343 127
1924 322 -50 -116 -64
1925 -195 -184 -7 108
1926 316 423 52 -93
1927 -271 -119 -21 -12
1928 180 -84 -99 -52
1929 10 -171 93 59
1930 150 25 107 285
1931 330 98 51 -18
1932 -14 136 -75 -14
1933 -195 -73 -69 -107
1934 -328 -80 -48 -31
1935 111 -72 -96 -80
1936 222 -85 -52 40
1937 -6 25 -52 -67
1938 -111 -144 -116 -90
1939 -84 66 13 -5
1940 153 258 250 278
1941 256 101 256 274
1942 257 96 138 28
1943 -190 -72 70 -117
1944 113 -20 63 88
1945 -225 -78 -14 -197
1946 -207 109 126 87
1947 62 -116 -118 -13
1948 91 212 86 -15
1949 99 -61 4 -32
1950 -233 -178 -94 -166
1951 -249 0 106 -53
1952 13 24 48 -40
1953 135 152 162 147
1954 2 -6 -98 -125
1955 -28 -100 -175 -160
1956 -251 -107 -150 -105
1957 -37 -33 41 228
1958 173 257 99 21
1959 163 -45 -8 -48
1960 -9 -23 -40 45
1961 -41 136 -30 -33
1962 -323 -154 -100 -100
1963 -275 -155 22 114
1964 256 -146 -111 -187
1965 -66 -46 170 279
1966 146 7 29 -22
1967 -60 -18 -82 -75
1968 20 -135 -85 8
1969 -67 127 79 -46
1970 30 90 -31 -91
1971 -294 -218 -104 -118
1972 -60 -63 108 315
1973 316 82 -30 -128
1974 -142 -201 -106 -129
1975 64 -52 -125 -106
1976 -129 -101 38 -21
1977 59 156 212 101
1978 213 20 21 -23
1979 74 -11 -9 84
1980 134 89 45 110
1981 210 186 -48 -43
1982 -87 -140 43 389
1983 691 558 373 68
1984 -121 21 116 -49
1985 -233 47 -82 -174
1986 -133 -28 49 134
1987 311 29 16 24
1988 111 -31 -39 -27
1989 -284 9 -230
References for the input data set:
Anomalies of the gridded data set are calculated by season with respect to the period 1950-89. The anomalies are then normalized by season with respect to the period 1851-1989. The longer period used for normalizing the data yields a smoother final time series than when 1950-89 is used. The time series is then calculated as the average of the available data in the index region for each season and year. The averaging region was chosen on the basis of analyses of Microwave Sounding Unit and GOES Precipitation Index precipitation anomalies in the period 1979-92 and 1986-92, respectively. Approximately sixteen (four) grid boxes contribute to the index for each season in the period 1950-81 (1982-89). The time series is then standardized by season with respect to 1950-89. The precipitation anomalies for the period 1950-89 are regressed onto the precipitation index, stratified by season, and the precipitation index scaled to have a standard deviation equal to the average regression value for the index region in each calendar season. Equatorial Pacific precipitation interannual variability exhibits a strong seasonal dependance, with average precipitation regressions of 203, 141, 114, and 135 mm month-1 in DJF, MAM, JJA, and SON, respectively. The preceeding normalization of the index is crude, and the index should not be used to make definitive statements about precipitation amounts in the tropical Pacific. An appropriate use of the scaled values of the index would be to say that it seems to rain more in one season than in another.