The global impacts of El Niño

One of the largest sources of information on seasonal timescales is the El Niño-Southern Oscillation (ENSO). ENSO consists of an irregular cycle in sea surface temperature in the Tropical Pacific, with associated changes in the atmospheric circulation. During a warm ‘El Niño’ event, SST anomalies in the central and eastern Tropical Pacific reach two to three degrees above average, while during a cold ‘La Niña’ event, SST anomalies reach two to three degrees below average. A strong El Niño or La Niña event substantially increases the likelihood of extra weather events both near and far. For example, locally it leads to heavy rain and flooding in Peru and drought in Indonesia. Further afield, there is evidence to suggest it affects the intensity of precipitation in the Indian Monsoon, the likelihood of drought in the American mid-west, and even European weather patterns.

Quantifying these so-called ‘teleconnections’, whereby ENSO impacts extreme weather around the globe, is important to understand sources of skill in seasonal forecasts. If we know a strong El Niño is on the way, we would like to quantify the resultant chance of severe flood or drought events, months in advance. But it is difficult to quantify these changes in probability of extreme events due to the short observational record.

In this project, we will produce simulations using world-leading climate models  to quantify the impact that ENSO has on extreme weather around the globe. This will provide an important source of information on seasonal timescales, enabling industry, policy makers, and the humanitarian sector to quantify the risks of natural hazards, and act accordingly.

Required skills: Good mathematical knowledge and basic programming skills