A significant El Niño has developed in the Pacific Ocean. Interest in this event is high because impacts across the U.S. and the world will likely be substantial. The images below show key spaceborne observations of the ocean and atmosphere as they are currently changing with El Niño. The images are produced by NASA’s Jet Propulsion Laboratory and partner agencies and compare the current conditions with the largest El Nino on record in 1997-1998, or with a 'normal' year for measurements that do not extend back to 1997.
Many of the images are designed to show a data "anomaly", revealing when data is outside of normal measurement ranges. For example, sea surface temperature (SST) data that stray from the normal range of variation are shown as SST anomalies. The color bar indicates how far from normal the measurements are.
El Niño Headlines
Sea Surface Temperature
The above images are of Sea Surface Temperature Anomalies (SSTA) of the 1998 (left) and 2016 (right) El Niño. The SSTA are derived from the Advanced Very High Resolution Radiometer (AVHRR) Optimally Interpolated SST that are provided by the Group for High Resolution Sea Surface Temperature (GHRSST) and also use NOAA's National Centers for Environmental Information (NCEI) climatology. The AVHRR instruments have been flying onboard NOAA’s operational polar orbiting satellites since 1981 beginning with NOAA-7 and continuing to present with NOAA-19. To view an animated version of this SST view, click here. For more information on this AVHRR Optimally Interpolated SST data, please visit this page.
Sea Surface Height Anomaly
These images compare ocean conditions during the 1997-1998 and 2015-2016 El Niño events. The 1998 image (left) is from the NASA/CNES TOPEX/Poseidon satellite. The 2016 image (right) is from the Ocean Surface Topography Mission/Jason-2 satellite.
The super El Niño of 2015-2016 is waning. Here we provide side by side comparisons of Pacific Ocean sea surface height (SSH) anomalies of what is presently happening to the Pacific Ocean El Niño signal with the famous 1997-1998 El Niño (which peaked in November 1997). The present El Niño, which peaked in January 2016, was longer lasting than the 1997-1998 episode and was larger in area. The El Niño of 2015-2016 was similar to the Niño of 1997-1998, but not an exact repeat. Each El Niño episode has a unique timing and variations in impacts. Also, remember that 2014 – 2015 was a weak, central Pacific Niño, so this one had a jump start. The El Niño of 2015-2016 was a continuing El Niño that first appeared in 2014-2015. Comparing present conditions with 1997-1998, a large area of the northeastern tropical Pacific (north of the equator) still contains a large area of positive (warmer than normal) heat content. The El Niño footprint is still strong. Looking ahead, many El Niño experts expect a transition to a La Niña, the cool sibling of El Niño. They put the probability of La Niña developing this summer or early fall at 70%.
The Jason-3 mission was successfully launched on January 17, 2016, and is already operational. Jason-2 and Jason-3 continue to provide an uninterrupted time-series that originated in 1992 with TOPEX/Poseidon. For the past 24 years, TOPEX/Poseidon, Jason-1, Jason-2 and Jason-3 have used space-based radar altimetry to collect sea surface height data of all the world's oceans. Here, these images are processed to highlight the interannual signal of SSH. The mean signal, seasonal signal, and the trend have been removed. To view an animated comparison, go here. For more information on SSH and the ocean altimetry missions, see the Ocean Surface Topography from Space web site.
Sea Surface Height Anomaly – California Coast
These images depict the sea-level anomaly (the difference between the total sea-level and the average sea-level for this time of year) off the coast of California during the 1997-1998 El Niño event (left) and the current conditions (right). For more information on SSH and the ocean altimetry missions, see the Ocean Surface Topography from Space web page.
These two graphics show the monthly oceanic precipitation totals (in millimeters) for the months of February 2015 and February 2016. Last year (2014-2015 winter), the majority of the precipitation near the equator in the Pacific was concentrated westward of 180-degrees longitude, whereas so far for this year (2015-2016 winter) the tropical precipitation has been concentrated further eastwards, in response to the warmer waters. As can be seen in the precipitation patterns, the majority of the precipitation systems near the western US this year have been associated with cold low pressure systems originating in the northeast Pacific, whereas the position of the El Niño-strengthened jet stream so far is such that its biggest influence has been felt in northern California and the Pacific Northwest.
These data are obtained from NASA’s Precipitation Processing System (PPS) at Goddard Space Flight Center, which handles all realtime and science data processing for the Global Precipitation Measurement GPM mission. GPM is a joint collaboration between NASA and the Japanese Aerospace Exploration Agency (JAXA), (http://pmm.nasa.gov). These data shown produced from the Integrated Multi-Satellite Retrievals for GPM (IMERG), which assembles multiple orbits of GPM and partner satellite data into a common grid every 30 minutes.
The relative humidity (RH) at the 500 hPa level, roughly in the middle of Earth’s troposphere that is related to weather variations, is used to highlight changes in atmospheric moisture in these images from the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite. The tropics and the midlatitude storm tracks are typically moist with drier air found in between these regions within the subtropics. The previous El Niño that peaked during Fall 2015/Winter 2016 led to much higher RH in the eastern tropical and subtropical Pacific with much drier conditions over Indonesia and southeast Asia. These dry and moist anomalies have greatly reduced in the last few months as we enter a neutral phase of ENSO. This animation shows the monthly AIRS Relative Humidity measurement from February 2015 through June 2016. For more information about AIRS, visit the AIRS web site.
While El Niño events have a significant impact on the entire Earth System, they are most starkly captured by the observed modulation in three parameters of the system: the Sea Surface Temperature (SST), the Sea Surface Height (SSH) and the near-surface ocean winds. In fact, the signature eastward-blowing anomalous surface winds in the Western and Central Tropical Pacific are the pre-cursor and the main driver of the El Niño events.
The images show the near-surface winds observed over the global oceans by NASA’s RapidScat. The ISS-RapidScat was launched aboard the International Space Stations (ISS) on September 21st 2014 and began providing high-quality data just couple of weeks later. The RapidScat instrument is a speedy and cost-effective replacement for NASA's QuikScat Earth satellite, which monitored ocean winds for ten years, providing essential measurements used in weather predictions and climate monitoring. So essential were QuikScat's measurements that when the satellite stopped collecting wind data in late 2009, NASA was challenged to quickly and cost-effectively conceive of a replacement. For more information visit the RapidScat web page, or interactively explore the data.
The left panel shows the monthly average winds for the period January 3, 2015 to February 3, 2015 while the right panel shows the anomalous winds for January 2016 (with respect to 2015). In both cases the colors represent the wind speed while the vectors illustrate the direction of the mean/anomaly winds. The El Niño signal is very clearly evident in the eastward blowing anomalous winds observed in the tropical western and central Pacific, as shown in the right panel. The El Niño signal is also seen in the anomalous stronger convergence into the tropical eastern Pacific, as evidenced by the stronger equator-ward winds observed in this region.
Cirrus clouds are ice clouds that occur in Earth’s upper troposphere typically between 6-10 miles in altitude. They are associated with tropical convection and wintertime storms in California. The cirrus cloud frequency shifted substantially during the Fall 2015/Winter 2016 when the previous El Niño peaked, and showed similar pattern shifts as relative humidity (RH) and Outgoing Longwave Radiation (OLR). These cirrus cloud anomalies have mostly faded in the last few months as we enter a neutral phase of ENSO. This animation shows the monthly Cirrus Clouds Frequency anomaly from February 2015 through June 2016. These images are from the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite. For more information, please visit the AIRS web site.
Outgoing Longwave Radiation
The Outgoing Longwave Radiation (OLR) is a measure of how much infrared energy is leaving Earth’s surface and atmosphere. The OLR depends on temperature, moisture, and clouds and is usually largest over the subtropical desert regions and the subtropical oceans, while it is lower in the high latitudes and in the cloudy and moist portions of the tropics. During the Fall 2015/Winter 2016 when the previous El Niño peaked, there was a clear shift towards reduced OLR in the tropical eastern Pacific that showed increased convective storms and moisture, with a strong increase in OLR in the tropical western Pacific. These OLR anomalies have mostly faded in the last few months as we enter a neutral phase of ENSO. This animation shows the monthly AIRS Outgoing Longwave Radiation anomaly from February 2015 through June 2016. These images are from the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite. For more information, please visit the AIRS web site.
Upper Tropospheric Water Vapor Anomalies from Aura MLS
These images from Microwave Limb Sounder (MLS) instrument on NASA's Aura spacecraft show the upper tropospheric water vapor anomalies near 10 km in height for 16 April 2015 and 2016 relative to an 11-year average. Under normal conditions, the SST over the tropical Pacific Ocean is warmest over its western end adjacent to Indonesia and coldest over its eastern end next to South America.
Storm activity over the oceans is associated with warm SSTs and moisture from such systems is lofted into the upper troposphere as seen in these plots. The red values indicate wetter than average, and blue drier than average conditions. The red features over the eastern Pacific ocean shown in winters of 2016 but not 2015 indicate that the SST has warmed off the coast of South and Central America and the upper atmosphere is much more humid than average due to increased tropical convection. For more information on this instrument and data, please visit the MLS web site.