For centuries Peruvian fishermen have watched with alarm as fish stocks suddenly shrunk every 3 to 7 years. They called this phenomenon El Niño (the Christ Child) as it always seemed to occur just after Christmas.

El Niño is an abnormal warming of the sea and is part of a wider phenomenon ENSO (El Niño/Southern Oscillation). In addition to a warm phase, El Niño itself, that typically lasts from 8 to 10 months, ENSO often also includes a cold phase, La Niña. The whole ENSO phenomenon normally lasts from 3 to 7 years.

El Niño is changing

Over recent decades the regular ENSO pattern has changed. Although it is not yet known exactly what causes ENSO, it is suspected that the departure from the regular pattern is partly linked to the greenhouse effect.

What is known with certainty is that the phenomenon does not only influence sea temperature off the Peruvian coast, but has an impact much further afield. It seems that even East Africa is affected by the ENSO phenomenon. After every El Niño drought is experienced - after a time lag - in the Kivu region, with a subsequent reduction in plant growth.

Satellite images are ideally suited to monitoring change processes. In this case they are used to identify changes in sea surface temperature and abnormal fluctuations in vegetation cover.
By revealing links between ENSO, climate and fluctuations in plant growth in East Africa, it will not only be easier to predict when the next El Niño will come, but also what areas will be affected and in what way.

SATELLITE DATA

NOAA-AVHRR

NASA Earth Observatory