FISHERY BULLETIN: VOL. 81, NO. 2 



The large rainfall amounts occurred in those years 

 when moderate/strong E 1 Ninos were setting in or oc- 

 curring. The frequency of occurrence of years with 

 abnormally heavy rainfall at Santiago and Valparaiso 

 appeared to decrease significantly after 1930 (based 

 on contents of table LTIB of Taulis 1934 and Table 1 

 here). At Santiago about 23% of the years 1861-1930 

 had rainfall amounts >500 mm, whereas only 8% 

 of the years 1931-80 had rainfall amounts in this 

 category; and at Valparaiso 30% of the years 1861- 

 1930 had rainfall amounts >600 mm, but only 6% 

 of the years 1931-80 had rainfall amounts in this 

 category (Table 3). Tables 4 and 5 show the rain- 

 fall category breakdown by decade for Santiago 

 and Valparaiso, and substantiate the decrease in 



wet years over the past 5 decades when signifi- 

 cant (moderate/strong) El Nihos were less fre- 

 quent. 



The smoothed rainfall plots for Santiago and 

 Valparaiso (Fig. 2) show prominent rainfall peaks 

 near and shortly after the turn of the century. Over 

 the 7-yr period 1899-1905 the average annual rainfall 

 was extremely high at La Serena, Santiago, and 

 Valparaiso (Table 6). During this period there were 

 three moderate/strong El Ninos (Quinn et al. 1978) 

 which resulted in very large rainfall amounts in 5 of 

 the 7 yr (table 5 of Quinn et al. 1981). 



The prominent El Niho/anti-El Nino-related rain- 

 fall departures are primarily confined to the Chilean 

 subtropics. Data from stations near lat. 40°S, at 



Table 3.— Percentage of years with annual rainfall (in millimeters) in designated categories over indicat- 

 ed periods for Santiago (lat. 33°26'S, long. 70°50'W) and Valparaiso (lat. 33°0TS, long. 71°39'W), Chile. 



TABLE 4. — Number of years per decade that annual rainfall was 

 within indicated categories, the average rainfall by decade, and 

 similar data for the 7-yr peak rainfall period (1899-1905) at Santiago 

 (lat. 33°26'S, long. 70°50'W), Chile. 



Table 5. — Number of years per decade that annual rainfall was 

 within indicated categories, the average rainfall by decade, and 

 similar data for the 7-yr peak rainfall period (1899-1905) at Val- 

 paraiso (lat. 33°01'S, long. 71°39'W), Chile. 



TABLE 6. — Average annual rainfall and departure from overall average (DA) (in 

 millimeters) for indicated periods at three subtropical Chilean stations: La Serena 

 (lat. 29°54'S, long. 71°15'W), Santiago (lat. 33°26'S, long 70°50'W), and Valparaiso 

 (lat. 33°01'S, long 71°39'W). 



1 For La Serena the precipitation record is limited to 1869-1980. 



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