Niño 3.4 Index and Sea Surface Temperature Anomaly Timeline: 1982-2017

  • Released Thursday, February 28, 2019

This visualization captures Sea Surface Temperature (SST) anomalies around the world from 1982 to 2017, along with a corresponding timeplot graph focusing on the Niño 3.4 SST Index region (5N-5S, 120W-170W), which represents average equatorial sea surface temperatures in the Pacific Ocean from about the International Date Line to the coast of South America. Highlighted in the timeline are the El Niño years, in which sea surface temperature anomalies peaked: 1982-1983, 1997-1998, and 2015-2016.

El Niño-Southern Oscillation (ENSO) phenomenon is an irregularly recurring climate pattern characterized by warmer (El Niño) and colder (La Niña) than usual ocean temperatures in the equatorial Pacific Ocean from about the International Date Line to the coast of South America. ENSO (El Niño, La Niña) events create a ripple effect of anticipated weather changes in far-spread regions on Earth. Weather changes associated with the ENSO phenomenon result in rainfall, temperature, vegetation and environmental anomaly conditions worldwide that directly favor outbreaks of infectious diseases of public health concern typically 2-3 months after.

During the last 20 years NASA scientist Dr. Assaf Anyamba and colleagues have been studying interannual climate variability patterns associated with ENSO events by monitoring the Niño 3.4 Index region over the Pacific Ocean (5N-5S, 120W-170W), along with rainfall, land surface temperature and vegetation anomaly data from NASA and NOAA.

Dr. Anyamba and colleagues conducted a scientific study - the first one to comprehensively assess the public health impacts of the major climate event on a global scale - that was open access published in the journal Nature Scientific Reports, with the title Global Disease Outbreaks Associated with the 2015-2016 El Niño event. According to the study, the 2015-2016 El Niño event brought weather conditions that triggered infectious disease outbreaks in teleconnected regions around the world. For example, plague and hantavirus in Colorado and New Mexico (in 2015), cholera in East Africa’s Tanzania (during 2015 and 2016), and dengue fever in Brazil and Southeast Asia (during 2015) among others.

The data visualization featured on this page provides a historical timeline of El Niño events for the period of 1982-2017 and illustrates the relationship between ENSO events (El Niño, La Niña) and the increase (red hues)/decrease (blue hues) of average Sea Surface Temperature (SST) Anomaly data over the Niño 3.4 Index region. The visualization showcases a global flat map with monthly Sea Surface Temperature (SST) anomaly data over water, along with a timeline plot of the ENSO Index (Niño 3.4 Index region SST anomaly) for the same period. The Nino 3.4 Index region SST with extents (5N-5S, 120W-170W) is the box region highlighted over the Pacific Ocean. Highlighted in the timeline are the strong El Niño years, in which Sea Surface Temperature (SST) anomalies peaked: 1982-1983, 1997-1998, and 2015-2016.

To learn more about the relationship between ENSO events and infectious disease outbreaks, please see the following data visualizations: