Climate variability and extreme events in the Zanatenco river basin, Chiapas

The interannual climatic variability is analyzed for the period 1961 to 2013 in the Zanatenco river basin, located in the Chiapas Coast, Mexico. The following variables were analyzed: precipitation and evaporation, both annual and daily maximum, as well as average and maximum temperatures. Likewise, the incidence of extreme hydrometeorological events associated to these climatological variables, such as floods and droughts, was analyzed. The floods are associated with greater rainfall the years, as well as the magnitude of the maximum daily rainfall events. The droughts are associated to the years with lower rainfall as well as extreme temperatures and extreme daily evaporation rates. The dry and rainy years are related to the presence of the global climatic phenomena of El Nino and La Nina. Annual precipitation and evaporation as well as the annual average temperature show an increasing trend. The extreme events of daily precipitation were presented from 2005 to 2013; the evaporation from 2001 to 2008; and of temperature from 1997 to 2006, corresponding to years with drought. The year with the maximum extreme rainfall event was recorded in 2006. The highest rate of daily evaporation occurred in 1970 and the highest maximum temperature occurred in the years 1997 to 1998. Thus, since 1997, droughts and floods have occurred more frequently and intensively in the region.