Relationship Between Drought Occurrence and ENSO in Southern Peru: A Copulas Analysis

Southern Peru is a semiarid area with frequent occurrence of drought events. Causes are often attributed to the occurrence of El Niño Phenomenon however; this relationship has not been fully confirmed.

This article analyzes the possible relationship between the occurrences of drought with ENSO in southern Peru under a copula’s analysis. For this purpose, the Standardized Precipitation Index is used for a period of three months (SPI3) as an indicator of drought and ENSO3-4, ENSO 1+2 AND ICEN sea surface temperature indices as indicators of El Niño Phenomenon occurrence. First, SPI should be estimated for every gage station in Candarave and Cairani irrigation district and the marginals distributions to be fitted to every group of data. Also, marginals to ENSO indexes should be evaluated too. Finally, copulas are built in base to marginals and looking for the best correlation. Copulas analysis is a statistical technic which will establish whether there are relationships between these variables and can be used as a basis for the development of mitigation plans against the occurrence of droughts. The results show a significant relationship between the occurrence of droughts and NINO34 index in Cairani but not relationchip in Candarave.

This article is the first advance about a more complex research to evaluate and build a copulas model to drought in this region of Peru.