The climate phenomena on the ocean influence greatly on the hydroclimatology of the Valley of the Cauca River (Colombia); especially "El Niño Southern Oscillation" event (ENSO); which is the cause of the climatic variability in time scales that go from months until decades. Due to this dependence, the correlation between 8 indicative variables of the climate both, in the Pacific and Atlantic Oceans with the mean monthly flow of 8 rivers from the Valley of the Cauca River were studied. The series cover a period average of 40 years 1957-1997. The results show the regional variations of the hydrological situation of the Valley of the Cauca River concerning the macroclimatic variables. The correlation coefficients indicate that the variables that introduce best association with the analyzed flows were in order: sea surface temperature of the Niño 3, Niño 3-4, Niño 4 regions and SOl, in t...

The ENSO phenomenon has a substantial effect on global climate variation; therefore, it is not surprising that its effects have a strong ecological and socio-economic impact, altering the feeding security world around. In front of this, it is understandable the awake world interest, not only by meteorology and oceanography specialists, but also among biologists, hydrologists, economists, sociologists and planners, among others. The present work shows some principal ecological effects in Colombia during the warm phase (El Niño) and cold phase (La Niña) pointed out the necessity to orientate the investigation in causes, consequences and impacts.

The climate phenomena on the ocean influence greatly on the hydroclimatology of the Valley of the Cauca River (Colombia); especially "El Niño Southern Oscillation" event (ENSO); which is the cause of the climatic variability in time scales that go from months until decades. Due to this dependence, the correlation between 8 indicative variables of the climate both, in the Pacific and Atlantic Oceans with the mean monthly flow of 8 rivers from the Valley of the Cauca River were studied. The series cover a period average of 40 years 1957-1997. The results show the regional variations of the hydrological situation of the Valley of the Cauca River concerning the macroclimatic variables. The correlation coefficients indicate that the variables that introduce best association with the analyzed flows were in order: sea surface temperature of the Niño 3, Niño 3-4, Niño 4 regions and SOl, in t...

El fenómeno ENOS, tiene un sustancial efecto sobre las variaciones del clima a nivel mundial; por lo tanto, no sorprende que sus efectos tengan un impacto ecológico y socioeconómico fuerte, alterando la seguridad alimentaria de los países a nivel mundial. Ante este panorama, es comprensible que haya despertado el mayor interés mundial, no sólo en los especialistas en meteorología y oceanografía sino también entre biólogos, ecólogos, físicos, matemáticos, agrónomos, hidrólogos, economistas, sociólogos y planificadores, entre otros. En el presente documento, se muestra algunos de los principales efectos ecológicos en Colombia durante las fases extremas cálida (El Niño) y fría (La Niña), indicando que es una necesidad urgente, orientar la investigación en sus causas, consecuencias e impactos.