Demystifying El Niño
Every few years, NASA declares we are in the midst of an El Niño event. From describing 2016’s El Niño as “Godzilla” and now calling this year’s “El Dud”, the accompanying media coverage on the topic tends to sensationalize rather than explain this incredibly complex and fascinating climate pattern.
This week, the Planet OS Datahub team has illustrated the conditions that produce El Niño in order to incorporate the vast amounts of available information behind the current series of interconnected global weather events. Drawing on the National Ocean and Atmospheric Agency’s (NOAA) Optimum Interpolation Sea Surface Temperature (OISST) Analysis, we will apply the data used by NASA climate scientists to visualize the current El Niño cycle and see how it compares to the infamous El Niño event of 2016.
Understanding El Niño
Characterized as the “warm phase” of the ENSO (El Niño Southern Oscillation), this notorious weather pattern is associated with a band of warm ocean temperatures that develop in the central and east-central Pacific Ocean. Soon after these changes in temperature, El Niño then brings high air pressure in the western Pacific and low air pressure in the eastern Pacific.
This atypical concoction of climate conditions brings notable changes to weather patterns worldwide. Historically, El Niño has unleashed deadly floods in Peru and a devastating drought in South Africa, while simultaneously quenching a five-year drought in Chile and bringing brilliant white powder to California’s ski resorts.
As a result, most know El Niño from its extremes. Nonetheless, it is important to note that El Niño does not necessarily entail climate chaos. Rather, it should be understood as a climatic pattern that has occurred for the past five million years, with some of the earliest societies organizing their agriculture and communities around its behavior.
However, history alone can fall short of providing a holistic understanding of this climate pattern. Below you will find visualizations and analysis from crunching the data on the most recent El Niño event.
El Niño: Then and Now
Despite El Niño’s five million year history, it is far from a routine climate event. Its patterns can vary significantly in both its intensity and seasonality.
Our Data Integration Engineer, Eneli Toodu produced the above visualizations comparing El Niño in 2016 to 2019 from the NOAA OISST dataset. This premier data set measures Sea Surface Temperature (SST) anomalies along the Pacific Ocean and Western Coast of the Americas. Because the NOAA OISST analysis is a combination of observations taken by satellites, ships, and buoys, the dataset has the ability to account for the variation caused by platform differences and sensor biases.
SST anomalies were chosen as they represent the most important factor in the formation of El Niño. When the waters of central and eastern tropical Pacific begin to rise to temperatures above average, weather agencies declare the beginning of El Niño. As the SST anomalies are taken at a depth of only a millimeter below the water’s surface, the temperature values serve as an interesting median between both the air and sea.
In the two graphics above, you can see El Niño and its impacts on sea surface temperature off the Western coast of the Americas. Side by side, the variations in intensity and water temperature fluctuations from 2016 compared to 2019 are prominent. The claim that this year’s El Niño is much weaker than that of 2016’s is validated with the visualization of data.
How Temperatures Brew Storms
Higher than average sea surface temperature causes water to evaporate more quickly and in greater quantities. The rising water vapor weakens the prevailing winds and extends the Pacific Jet Stream across North America.
Increased rates of evaporation also signal higher rates of precipitation. Looking at the maps above, we can observe that these high temperatures can be seen most clearly along the coast of California and Peru. Indeed, both areas these areas witnessed heavy downpours and flooding in the past two months.
As a phenomenon, no single weather event can be pinpointed as a result of El Niño. However, when observed globally, El Niño can be used to connect patterns in weather events across the Pacific. Just two weeks ago, we investigated how El Niño’s summer droughts and winter rains may explain the higher rate and severity of mudslides in both Australia and Southern California.
Moving Forward
El Niño can bring dangerous levels of rainfall, drought, and other extreme fluctuations in weather. Yet, by understanding these patterns of climate behavior, we can more accurately predict which atmospheric conditions to expect and engage more effective responses.
With Planet OS Datahub’s rich library of climate and environmental data, the risk and anticipation surrounding El Niño can be reduced. With over 2,100 variables taken from all over the globe, climate scientists, industries, and communities can collaborate to develop our understanding of how climatic events impact us and what actions can be taken to increase our preparedness.
DIY Data
To apply Datahub’s available datasets into informative and useful tools, click here to access a Github notebook that provides a step by step guide on how to create your own active El Niño animations.
Many of the datasets made available through the Planet OS Datahub have been at the request of our users. For those who require a consolidated, easy to use, resource for accessing large and complex material that the Datahub does not already offer, please reach out to the team and we will work toward bringing it onboard. For more information check out the Planet OS Datahub.
