Earth Science from Space (Satellites)

Successful Ocean-Monitoring Satellite Mission Ends

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Esprit Smith, Jet Propulsion Laboratory, Pasadena, Calif.
esprit.smith@jpl.nasa.gov

Pascale Bresson, CNES, Paris, France
pascale.bresson@cnes.fr

Raphaël Sart, CNES, Paris, France
raphael.sart@cnes.fr

John Leslie, NOAA National Environmental Satellite and Information Service, Silver Spring, Md.
john.leslie@noaa.gov

Neil Fletcher. EUMETSAT, Darmstadt, Germany
neil.fletcher@eumetsat.int

 

JASON2-2-16
Jason-2/OSTM contributed to a long-term record of global sea levels. This image shows areas in the Pacific Ocean where sea levels were lower (blues) or higher (reds) than normal during the first week of January 2018. Credit: NASA/JPL-Caltech

 

The Jason-2/Ocean Surface Topography Mission (OSTM), the third in a U.S.-European series of satellite missions designed to measure sea surface height, successfully ended its science mission on Oct. 1. NASA and its mission partners made the decision to end the mission after detecting deterioration in the spacecraft’s power system.

Jason-2/OSTM, a joint NASA mission with the French space agency Centre National d’Etudes Spatiales (CNES), the National Oceanic and Atmospheric Administration (NOAA), and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), launched in June 2008. The mission extended the long-term record of sea surface height measurements started by the NASA-CNES TOPEX/Poseidon and Jason-1 missions. Jason-2/OSTM’s 11-year lifetime well exceeded its three-year design life. These measurements are being continued by its successor, Jason-3, launched in 2016.

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NASA Selects Missions to Study Our Sun, Its Effects on Space Weather

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Grey Hautaluoma / Karen Fox
NASA Headquarters, Washington
grey.hautaluoma-1@nasa.gov / karen.c.fox@nasa.gov

 

A constant outflow of solar material streams out from the Sun, depicted here in an artist’s rendering. On June 20, 2019, NASA selected two new missions – the Polarimeter to Unify the Corona and Heliosphere (PUNCH) mission and Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites (TRACERS) – to study the origins of this solar wind and how it affects Earth. Together, the missions support NASA’s mandate to protect astronauts and technology in space from such radiation. Credits: NASA


NASA has selected two new missions to advance our understanding of the Sun and its dynamic effects on space. One of the selected missions will study how the Sun drives particles and energy into the solar system and a second will study Earth’s response.

The Sun generates a vast outpouring of solar particles known as the solar wind, which can create a dynamic system of radiation in space called space weather. Near Earth, where such particles interact with our planet’s magnetic field, the space weather system can lead to profound impacts on human interests, such as astronauts’ safety, radio communications, GPS signals, and utility grids on the ground. The more we understand what drives space weather and its interaction with the Earth and lunar systems, the more we can mitigate its effects – including safeguarding astronauts and technology crucial to NASA’s Artemis program to the Moon.

 

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OCO-3 Ready to Extend NASA’s Study of Carbon

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 Written by Jane Platt
 Jet Propulsion Laboratory, Pasadena, California

 

OCO-3 sits on the large vibration table (known as the “shaker”) in the Environmental Test Lab at the Jet Propulsion Laboratory. Credit: NASA/JPL-Caltech

 

When the Orbiting Carbon Observatory 3, OCO-3, heads to the International Space Station, it will bring a new view – literally – to studies of Earth’s carbon cycle.

From its perch on the space station, OCO-3 will observe near-global measurements of carbon dioxide on land and sea, from just after sunrise to just before sunset. That makes it far more versatile and powerful than its predecessior, OCO-2.

 

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Solar Storms Can Drain Electrical Charge Above Earth

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Written by Carol Rasmussen
NASA’s Earth Science News Team

A solar eruption on Sept. 26, 2014, seen by NASA’s Solar Dynamics Observatory. If erupted solar material reaches Earth, it can deplete the electrons in the upper atmosphere in some locations while adding electrons in others, disrupting communications either way. Credit: NASA

 

New research on solar storms finds that they not only can cause regions of excessive electrical charge in the upper atmosphere above Earth’s poles, they also can do the exact opposite: cause regions that are nearly depleted of electrically charged particles. The finding adds to our knowledge of how solar storms affect Earth and could possibly lead to improved radio communication and navigation systems for the Arctic. 

A team of researchers from Denmark, the United States and Canada made the discovery while studying a solar storm that reached Earth on Feb. 19, 2014. The storm was observed to affect the ionosphere in all of Earth’s northern latitudes. Its effects on Greenland were documented by a network of global navigation satellite system, or GNSS, stations as well as geomagnetic observatories and other resources. Attila Komjathy of NASA’s Jet Propulsion Laboratory, Pasadena, California, developed software to process the GNSS data and helped with the data processing. The results were published in the journal Radio Science.

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GRACE Mission: 15 Years of Watching Water on Earth

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Written by Carol Rasmussen
NASA Earth Science News Team


Artists_concept_of_the_Gravity_Recovery_and_Climate_Experiment_GRACE_from_December_2002.jpg
Artists concept of the Gravity Recovery and Climate Experiment GRACE from December 2002


Fast Facts

  • In 15 years of operations, the GRACE satellite mission has revolutionized our view of how water moves and is stored on Earth.
  • GRACE measures changes in the local pull of gravity as water shifts around Earth due to changing seasons, weather and climate processes.
  • Among other innovations, GRACE gave us the first space-based view of water beneath Earth’s surface, giving insight into where aquifers may be shrinking or dry soils contributing to drought.
  • The GRACE Follow-On mission, launching in early 2018, will extend GRACE’s innovative measurements

 

“Revolutionary” is a word you hear often when people talk about the GRACE mission. Since the twin satellites of the U.S./German Gravity Recovery and Climate Experiment  launched on March 17, 2002, their data have transformed scientists’ view of how water moves and is stored around the planet.

“With GRACE, we effectively created a new field of spaceborne remote sensing: tracking the movement of water via its mass,” said Michael Watkins, the original GRACE project scientist and now director of NASA’s Jet Propulsion Laboratory, Pasadena, California.

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NASA Satellite Finds Unreported Source of Toxic Air Pollution

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Human-made sulfur dioxide emissions from a medium-size power plant
New research has detected smaller sulfur dioxide concentrations and sources around the world, including human-made sources such as medium-size power plants and oil-related activities.
Credit: EPA
 
Data from NASA’s Aura spacecraft, illustrated here, were analyzed by scientists to produce improved estimates of sulfur dioxide sources and concentrations worldwide between 2005 and 2014.

Credit: NASA

Using a new satellite-based method, scientists at NASA, Environment and Climate Change Canada, and two universities have located 39 unreported and major human-made sources of toxic sulfur dioxide emissions.

A known health hazard and contributor to acid rain, sulfur dioxide (SO2) is one of six air pollutants regulated by the U.S. Environmental Protection Agency. Current, sulfur dioxide monitoring activities include the use of emission inventories that are derived from ground-based measurements and factors, such as fuel usage. The inventories are used to evaluate regulatory policies for air quality improvements and to anticipate future emission scenarios that may occur with economic and population growth.

But, to develop comprehensive and accurate inventories, industries, government agencies and scientists first must know the location of pollution sources.

“We now have an independent measurement of these emission sources that does not rely on what was known or thought known,” said Chris McLinden, an atmospheric scientist with Environment and Climate Change Canada in Toronto and lead author of the study published this week in Nature Geosciences. 

“When you look at a satellite picture of sulfur dioxide, you end up with it appearing as hotspots – bull’s-eyes, in effect — which makes the estimates of emissions easier.”

The 39 unreported emission sources, found in the analysis of satellite data from 2005 to 2014, are clusters of coal-burning power plants, smelters, oil and gas operations found notably in the Middle East, but also in Mexico and parts of Russia. In addition, reported emissions from known sources in these regions were — in some cases — two to three times lower than satellite-based estimates. 

Altogether, the unreported and underreported sources account for about 12 percent of all human-made emissions of sulfur dioxide – a discrepancy that can have a large impact on regional air quality, said McLinden.

The research team also located 75 natural sources of sulfur dioxide — non-erupting volcanoes slowly leaking the toxic gas throughout the year. While not necessarily unknown, many volcanoes are in remote locations and not monitored, so this satellite-based data set is the first to provide regular annual information on these passive volcanic emissions.

“Quantifying the sulfur dioxide bull’s-eyes is a two-step process that would not have been possible without two innovations in working with the satellite data,” said co-author Nickolay Krotkov, an atmospheric scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. 

First was an improvement in the computer processing that transforms raw satellite observations from the Dutch-Finnish Ozone Monitoring Instrument aboard NASA’s Aura spacecraft into precise estimates of sulfur dioxide concentrations. Krotkov and his team now are able to more accurately detect smaller sulfur dioxide concentrations, including those emitted by human-made sources such as oil-related activities and medium-size power plants. 

Being able to detect smaller concentrations led to the second innovation. McLinden and his colleagues used a new computer program to more precisely detect sulfur dioxide that had been dispersed and diluted by winds. They then used accurate estimates of wind strength and direction derived from a satellite data-driven model to trace the pollutant back to the location of the source, and also to estimate how much sulfur dioxide was emitted from the smoke stack.

“The unique advantage of satellite data is spatial coverage,” said Bryan Duncan, an atmospheric scientist at Goddard. 

“This paper is the perfect demonstration of how new and improved satellite datasets, coupled with new and improved data analysis techniques, allow us to identify even smaller pollutant sources and to quantify these emissions over the globe.”

The University of Maryland, College Park, and Dalhousie University in Halifax, Nova Scotia, contributed to this study.

For more information about, and access to, NASA’s air quality data, visit: http://so2.gsfc.nasa.gov/

NASA uses the vantage point of space to increase our understanding of our home planet, improve lives, and safeguard our future. NASA develops new ways to observe and study Earth’s interconnected natural systems with long-term data records. The agency freely shares this unique knowledge and works with institutions around the world to gain new insights into how our planet is changing. 

For more information about NASA Earth science research, visit: http://www.nasa.gov/earth

NASA Study Solves Two Mysteries About Wobbling Earth

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Earth does not always spin on an axis running through its poles. Instead, it wobbles irregularly over time, drifting toward North America throughout most of the 20th Century (green arrow). That direction has changed drastically due to changes in water mass on Earth. Credit: NASA/JPL-Caltech


Using
satellite data on how water moves around Earth, NASA scientists have solved two mysteries about wobbles in the planet’s rotation — one new and one more than a century old. The research may help improve our knowledge of past and future climate. 

Although a desktop globe always spins smoothly around the axis running through its north and south poles, a real planet wobbles. Earth’s spin axis drifts slowly around the poles; the farthest away it has wobbled since observations began is 37 feet (12 meters). These wobbles don’t affect our daily life, but they must be taken into account to get accurate results from GPS, Earth-observing satellites and observatories on the ground. 

In a paper ‘Climate–Driven Polar Motion: 2003–2015 (PDF)‘ published today in Science Advances, Surendra Adhikari and Erik Ivins of NASA’s Jet Propulsion Laboratory, Pasadena, California, researched how the movement of water around the world contributes to Earth’s rotational wobbles. Earlier studies have pinpointed many connections between processes on Earth’s surface or interior and our planet’s wandering ways. For example, Earth’s mantle is still readjusting to the loss of ice on North America after the last ice age, and the reduced mass beneath that continent pulls the spin axis toward Canada at the rate of a few inches each year. But some motions are still puzzling.


A Sharp Turn To The East

Before about 2000, Earth’s spin axis was drifting toward Canada (green arrow, left globe). JPL scientists calculated the effect of changes in water mass in different regions (center globe) in pulling the direction of drift eastward and speeding the rate (right globe). Credit: NASA/JPL-Caltech

Around the year 2000, Earth’s spin axis took an abrupt turn toward the east and is now drifting almost twice as fast as before, at a rate of almost 7 inches (17 centimeters) a year. “It’s no longer moving toward Hudson Bay, but instead toward the British Isles,” said Adhikari. “That’s a massive swing.” Adhikari and Ivins set out to explain this unexpected change.

Scientists have suggested that the loss of mass from Greenland and Antarctica’s rapidly melting ice sheet could be causing the eastward shift of the spin axis. The JPL scientists assessed this idea using observations from the NASA/German Aerospace Center Gravity Recovery and Climate Experiment (GRACE) satellites, which provide a monthly record of changes in mass around Earth. Those changes are largely caused by movements of water through everyday processes such as accumulating snowpack and groundwater depletion. They calculated how much mass was involved in water cycling between Earth’s land areas and its oceans from 2003 to 2015, and the extent to which the mass losses and gains pulled and pushed on the spin axis.

Adhikari and Ivins’ calculations showed that the changes in Greenland alone do not generate the gigantic amount of energy needed to pull the spin axis as far as it has shifted. In the Southern Hemisphere, ice mass loss from West Antarctica is pulling, and ice mass gain in East Antarctica is pushing, Earth’s spin axis in the same direction that Greenland is pulling it from the north, but the combined effect is still not enough to explain the speedup and new direction. Something east of Greenland has to be exerting an additional pull.

The researchers found the answer in Eurasia. 

“The bulk of the answer is a deficit of water in Eurasia: the Indian subcontinent and the Caspian Sea area,” Adhikari said. 

The finding was a surprise. This region has lost water mass due to depletion of aquifers and drought, but the loss is nowhere near as great as the change in the ice sheets. 

So why did the smaller loss have such a strong effect? The researchers say:

“It’s because the spin axis is very sensitive to changes occurring around 45 degrees latitude, both north and south. “This is well explained in the theory of rotating objects,” Adhikari explained. “That’s why changes in the Indian subcontinent, for example, are so important.””


New Insight on an Old Wobble
In the process of solving this recent mystery, the researchers unexpectedly came up with a promising new solution to a very old

The relationship between continental water mass and the east-west wobble in Earth’s spin axis. Losses of water from Eurasia correspond to eastward swings in the general direction of the spin axis (top), and Eurasian gains push the spin axis westward (bottom). Credit: NASA/JPL-Caltech

problem, as well. One particular wobble in Earth’s rotation has perplexed scientists since observations began in 1899. Every six to 14 years, the spin axis wobbles about 20 to 60 inches (0.5 to 1.5 meters) either east or west of its general direction of drift. “Despite tremendous theoretical and modeling efforts, no plausible mechanism has been put forward that could explain this enigmatic oscillation,” Adhikari said.

Lining up a graph of the east-west wobble during the period when GRACE data were available against a graph of changes in continental water storage for the same period, the JPL scientists spotted a startling similarity between the two. Changes in polar ice appeared to have no relationship to the wobble — only changes in water on land. Dry years in Eurasia, for example, corresponded to eastward swings, while wet years corresponded to westward swings.

When the researchers input the GRACE observations on changes in land water mass from April 2002 to March 2015 into classic physics equations that predict pole positions, they found that the results matched the observed east-west wobble very closely. “This is much more than a simple correlation,” coauthor Ivins said. “We have isolated the cause.”

The discovery raises the possibility that the 115-year record of east-west wobbles in Earth’s spin axis may, in fact, be a remarkably good record of changes in land water storage. “That could tell us something about past climate — whether the intensity of drought or wetness has amplified over time, and in which locations,” said Adhikari. 

“Historical records of polar motion are both globally comprehensive in their sensitivity and extraordinarily accurate,” said Ivins. “Our study shows that this legacy data set can be used to leverage vital information about changes in continental water storage and ice sheets over time.”

GRACE is a joint NASA mission with the German Aerospace Center (DLR) and the German Research Center for Geosciences (GFZ), in partnership with the University of Texas at Austin. For more information on the mission, visit: http://grace.jpl.nasa.gov or http://www.csr.utexas.edu/grace

NASA uses the vantage point of space to increase our understanding of our home planet, improve lives and safeguard our future. NASA develops new ways to observe and study Earth’s interconnected natural systems with long-term data records. The agency freely shares this unique knowledge and works with institutions around the world to gain new insights into how our planet is changing.

For more information about NASA’s Earth science activities, visit: http://www.nasa.gov/earth

New NASA Web Portal Shines Beacon on Rising Seas

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Fort Lauderdale, Florida, is at risk from rising sea levels. Credit: Dave/Flickr Creative Commons/CC BY 2.0

 

Sea level rise is a critical global issue affecting millions across our planet. A new Web portal developed by NASA’s Jet Propulsion Laboratory, Pasadena, California, gives researchers, decision makers and the public alike a resource to stay up to date with the latest developments and scientific findings in this rapidly advancing field of study. 

The portal, “Sea Level Change: Observations from Space,” is online at: https://sealevel.nasa.gov/

The portal’s key features include:
 

  • “Understanding Sea Level,” a summary of decades of scientific research that has shaped our knowledge of sea level rise: its causes, including a warming, expanding ocean and melting ice on land; projections of future sea level rise; and ways in which humanity might adapt, largely drawn from NASA data.
     
  • An interactive data analysis tool, launching in mid-2016, that will allow direct access to NASA datasets on sea level. Users will be able to manipulate these datasets to automatically generate charts, graphs and maps of sea surface height, temperature and other factors. The analysis tool will also allow users to make forecasts of future conditions, as well as “hindcasts” — retroactive calculations of past trends and conditions.
     
  • News highlights and feature stories with strong visual elements that explore the findings of sea level researchers in detail.
     
  • An extensive library of published papers on sea level-related topics, hyperlinked to individual citations throughout “Understanding Sea Level.”
     
  • A multimedia section with dynamic still and video imagery, and a glossary of sea level terms.

  • A “frequently asked questions” section maintained by sea level scientists. Users can submit questions to scientists and data managers.


The website is optimized for most mobile devices, including smartphones and tablets.

“Sea Level Change: Observations from Space” is managed by a team led by JPL scientist Carmen Boening. The team is part of the NASA Sea Level Change Team research group. 

“With sea levels rising globally, as observed by satellites over the past decades, sea level change is a hot topic in climate research,” Boening said. “This new tool provides a NASA resource for researchers and a wealth of information for members of the public seeking a deeper understanding of sea level change.”

For more information on NASA’s Earth science activities, visit: http://www.nasa.gov/earth and http://climate.nasa.gov

JPL is a division of the California Institute of Technology in Pasadena.

 

 

 

 

 

NASA, Japan Make ASTER Earth Data Available At No Cost

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In March 2016, ASTER captured the eruption of Nicaragua’s Momotombo volcano with its visible and thermal infrared bands. The ash plume is depicted by the visible bands in blue-gray; the thermal infrared bands show hot lava flows in yellow and the active summit crater in white. Vegetation is red. Credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Beginning today, all Earth imagery from a prolific Japanese remote sensing instrument operating aboard NASA’s Terra spacecraft since late 1999 is now available to users everywhere at no cost.

The public will have unlimited access to the complete 16-plus-year database for Japan’s Ministry of Economy, Trade and Industry (METI) Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument, which images Earth to map and monitor the changing surface of our planet. ASTER’s database currently consists of more than 2.95 million individual scenes. The content ranges from massive scars across the Oklahoma landscape from an EF-5 tornado and the devastating aftermath of flooding in Pakistan, to volcanic eruptions in Iceland and wildfires in California.

Previously, users could access ASTER’s global digital topographic maps of Earth online at no cost, but paid METI a nominal fee to order other ASTER data products. 

In announcing the change in policy, METI and NASA cited ASTER’s longevity and continued strong environmental monitoring capabilities. Launched in 1999, ASTER has far exceeded its five-year design life and will continue to operate for the foreseeable future as part of the suite of five Earth-observing instruments on Terra.

“We anticipate a dramatic increase in the number of users of our data, with new and exciting results to come,” said Michael Abrams, ASTER science team leader at NASA’s Jet Propulsion Laboratory in Pasadena, California, home to ASTER’s U.S. science team. ASTER data are processed into products using algorithms developed at JPL and the National Institute of Advanced Industrial Science and Technology (AIST) in Japan. A joint U.S./Japan science team validates and calibrates the instrument and data products.

ASTER is used to create detailed maps of land surface temperature, reflectance and elevation. The instrument acquires images in visible and thermal infrared wavelengths, with spatial resolutions ranging from about 50 to 300 feet (15 to 90 meters). ASTER data cover 99 percent of Earth’s landmass and span from 83 degrees north latitude to 83 degrees south. A single downward-looking ASTER scene covers an area on the ground measuring about 37-by-37 miles (60-by-60-kilometers).

ASTER uses its near-infrared spectral band and downward- and backward-viewing telescopes to create stereo-pair images, merging two slightly offset two-dimensional images to create the three-dimensional effect of depth. Each elevation measurement point in the data is 98 feet (30 meters) apart.

The broad spectral coverage and high spectral resolution of ASTER provide scientists in numerous disciplines with critical information for surface mapping and monitoring of dynamic conditions and changes over time. Example applications include monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud morphology and physical properties, evaluating wetlands, monitoring thermal pollution, monitoring coral reef degradation, mapping surface temperatures of soils and geology, and measuring surface heat balance.

ASTER data are now available via electronic download from NASA’s Land Processes Distributed Active Archive Center (LP DAAC) at the U.S. Geological Survey’s (USGS) Earth Resources Observation and Science Center in Sioux Falls, South Dakota, and from AIST. To access the data, visit: https://lpdaac.usgs.gov/dataset_discovery/aster or https://gbank.gsj.jp/madas/

NASA uses the vantage point of space to increase our understanding of our home planet, improve lives and safeguard our future. NASA develops new ways to observe and study Earth’s interconnected natural systems with long-term data records. The agency freely shares this unique knowledge and works with institutions around the world to gain new insights into how our planet is changing.

For more information about ASTER, visit: http://asterweb.jpl.nasa.gov/

For more information on NASA’s Terra mission, visit: http://terra.nasa.gov

For more information about NASA’s Earth science activities, visit: http://www.nasa.gov/earth

A Still-Growing El Niño Set to Bear Down on US

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The latest satellite image of Pacific sea surface heights from Jason-2 (left) differs slightly from one 18 years ago from Topex/Poseidon (right). In Dec. 1997, sea surface height was more intense and peaked in November. This year the area of high sea levels is less intense but considerably broader. (Credit: NASA/JPL-Caltech)

 


The current strong El Niño brewing in the Pacific Ocean shows no signs of waning, as seen in the latest satellite image from the U.S./European Ocean Surface Topography Mission (OSTM)/Jason-2 mission. 

El Niño 2015 has already created weather chaos around the world. Over the next few months, forecasters expect the United States to feel its impacts as well. 

The latest Jason-2 image bears a striking resemblance to one from December 1997, by Jason-2’s predecessor, the NASA/Centre National d’Etudes Spatiales (CNES) Topex/Poseidon mission, during the last large El Niño event. Both reflect the classic pattern of a fully developed El Niño. The images can be viewed at:

http://sealevel.jpl.nasa.gov/elnino2015/index.html

The images show nearly identical, unusually high sea surface heights along the equator in the central and eastern Pacific: the signature of a big and powerful El Niño. Higher-than-normal sea surface heights are an indication that a thick layer of warm water is present.

El Niños are triggered when the steady, westward-blowing trade winds in the Pacific weaken or even reverse direction, triggering a dramatic warming of the upper ocean in the central and eastern tropical Pacific. Clouds and storms follow the warm water, pumping heat and moisture high into the overlying atmosphere. These changes alter jet stream paths and affect storm tracks all over the world.

This year’s El Niño has caused the warm water layer that is normally piled up around Australia and Indonesia to thin dramatically, while in the eastern tropical Pacific, the normally cool surface waters are blanketed with a thick layer of warm water. This massive redistribution of heat causes ocean temperatures to rise from the central Pacific to the Americas. It has sapped Southeast Asia’s rain in the process, reducing rainfall over Indonesia and contributing to the growth of massive wildfires that have blanketed the region in choking smoke. 

El Niño is also implicated in Indian heat waves caused by delayed monsoon rains, as well as Pacific island sea level drops, widespread coral bleaching that is damaging coral reefs, droughts in South Africa, flooding in South America and a record-breaking hurricane season in the eastern tropical Pacific. Around the world, production of rice, wheat, coffee and other crops has been hit hard by droughts and floods, leading to higher prices. 

In the United States, many of El Niño’s biggest impacts are expected in early 2016. Forecasters at the National Oceanic and Atmospheric Administration favor an El Niño-induced shift in weather patterns to begin in the near future, ushering in several months of relatively cool and wet conditions across the southern United States, and relatively warm and dry conditions over the northern United States. The latest El Niño forecast from NOAA’s Climate Prediction Center is at: http://www.cpc.ncep.noaa.gov/

While scientists still do not know precisely how the current El Niño will affect the United States, the last large El Niño in 1997-98 was a wild ride for most of the nation. The “Great Ice Storm” of January 1998 crippled northern New England and southeastern Canada, but overall, the northern tier of the United States experienced long periods of mild weather and meager snowfall. Meanwhile, across the southern United States, a steady convoy of storms slammed most of California, moved east into the Southwest, drenched Texas and — pumped up by the warm waters of the Gulf of Mexico — wreaked havoc along the Gulf Coast, particularly in Florida. 

“In 2014, the current El Niño teased us — wavering off and on,” said Josh Willis, project scientist for the Jason missions at JPL. “But in early 2015, atmospheric conditions changed, and El Niño steadily expanded in the central and eastern Pacific. Although the sea surface height signal in 1997 was more intense and peaked in November of that year, in 2015, the area of high sea levels is larger. This could mean we have not yet seen the peak of this El Niño.”

During normal, non-El Niño conditions, the amount of warm water in the western equatorial Pacific is so large that sea levels are about 20 inches (50 centimeters) higher in the western Pacific than in the eastern Pacific. “You can see it in the latest Jason-2 image of the Pacific,” said Willis. “The 8-inch [20-centimeter] drop in the west, coupled with the 10-inch [25-centimeter] rise in the east, has completely wiped out the tilt in sea level we usually have along the equator.”

The new Jason-2 image shows that the amount of extra-warm surface water from the current El Niño (depicted in red and white shades) has continuously increased, especially in the eastern Pacific within 10 degrees latitude north and south of the equator. In the western Pacific, the area of low sea level (blue and purple) has decreased somewhat from late October. The white and red areas indicate unusual patterns of heat storage. In the white areas, the sea surface is between 6 and 10 inches (15 to 25 centimeters) above normal, while in the red areas, it is about 4 inches (10 centimeters) above normal. The green areas indicate normal conditions. The height of the ocean water relates, in part, to its temperature, and is an indicator of the amount of heat stored in the ocean below. 

Within this area, surface temperatures are greater than 86 degrees Fahrenheit (30 degrees Celsius) in the central equatorial Pacific and near 70 degrees Fahrenheit (21 degrees Celsius) off the coast of the Americas. This El Niño signal encompasses a surface area of 6 million square miles (16 million square kilometers) — more than twice as big as the continental United States. 

While no one can predict the exact timing or intensity of U.S. El Niño impacts, for drought-stricken California and the U.S. West, it’s expected to bring some relief. 

“The water story for much of the American West over most of the past decade has been dominated by punishing drought,” said JPL climatologist Bill Patzert. “Reservoir levels have fallen to record or near-record lows, while groundwater tables have dropped dangerously in many areas. Now we’re preparing to see the flip side of nature’s water cycle — the arrival of steady, heavy rains and snowfall.” 

In 1982-83 and 1997-98, large El Niños delivered about twice the average amount of rainfall to Southern California, along with mudslides, floods, high winds, lightning strikes and high surf. But Patzert cautioned that El Niño events are not drought busters. “Over the long haul, big El Niños are infrequent and supply only seven percent of California’s water,” he said.

“Looking ahead to summer, we might not be celebrating the demise of this El Niño,” cautioned Patzert. “It could be followed by a La Niña, which could bring roughly opposite effects to the world’s weather.” 

La Niñas are essentially the opposite of El Niño conditions. During a La Niña episode, trade winds are stronger than normal, and the cold water that normally exists along the coast of South America extends to the central equatorial Pacific. La Niña episodes change global weather patterns and are associated with less moisture in the air over cooler ocean waters. This results in less rain along the coasts of North and South America and along the central and eastern equatorial Pacific, and more rain in the far Western Pacific.

El Niño events are part of the long-term, evolving state of global climate, for which measurements of sea surface height are a key indicator. 

For an animation of the evolution of the 2015 and 1997 El Niños, visit: https://sealevel.jpl.nasa.gov/elnino2015/2015-animated.gif

For more information on how NASA studies El Niño, visit: http://climatesciences.jpl.nasa.gov/enso

To learn more about NASA’s satellite altimetry programs, visit: http://sealevel.jpl.nasa.gov

For more information about NASA’s Earth science activities, visit: http://www.nasa.gov/earth