Oceanic Niño Index as a Tool to Determine the Effect of Weather on Coffee Plantation in Colombia

The aim was assess the reliability of the Oceanic Niño Index (ONI) as appropriate index to adjust early weather warnings for the coffee sector in Colombia. The study was conducted in the National Coffee Research Center (Cenicafé), Manizales, Colombia between January 2013 and June 2014. Simple correlations between ONI and number of rainy days, at monthly scale, were done. Correlation coefficients (R) and P-values for every month and station were calculated, and twelve maps (one per each month) showing if the correlation is positive or negative and the significance were used in order to determine the ONI effect´s on rainfall at spatial and temporal scales. The results show that the effect of the ONI on the number of days with rain is differential and depends on the area being analyzed. The effect is similar in the central and southern coffee regions, whose behavior is totally different from the coffee zone of the Sierra Nevada de Santa Marta (northern coffee zone). In the north, the ONI has a positive relation with the number of days with rain in the first half of the year, similar to the effect on the South Eastern of the U.SA. In conclusion, ONI cannot be used widely (time and space) as an index to adjust early warning systems in the coffee growth zone in Colombia.