Effect of ENSO on the mid-summer drought in Veracruz State, Mexico

Abstract

This paper shows the effect of El Niño/Southern Oscillation (ENSO) on the mid-summer drought at Veracruz state. To analyze this effect we compared the average monthly precipitation of the years with El Niño and that for not El Niño years of 51 climatological stations. The period of record for each station varied from 25 to 75 years. The results show that during the event El Niño the mid-summer drought is diminished or disappeared in almost all the Veracruz state. This occurs during the months of July and August. However, on the highlands of central Veracruz the intensity of mid-summer drought is incremented. Finally we applied the variance comparison test of Fisher to know if the variation of the precipitation in July and August was random or originated from El Niño. The statistical analysis shows that the variation of the precipitation in some regions of Veracruz states is significant from .1 to 5.