Parts of the New York City metropolitan area are sinking and rising at different rates due to factors ranging from land-use practices to long-lost glaciers, scientists have found. While the elevation changes seem small – fractions of inches per year – they can enhance or diminish local flood risk linked to sea level rise.

The new study was published Wednesday in Science Advances by a team of researchers from NASA’s Jet Propulsion Laboratory in Southern California and Rutgers University in New Jersey. The team analyzed upward and downward vertical land motion – also known as uplift and subsidence – across the metropolitan area from 2016 to 2023 using a remote sensing technique called interferometric synthetic aperture radar (InSAR). The technique combines two or more 3D observations of the same region to reveal surface motion or topography.

Much of the motion they observed occurred in areas where prior modifications to Earth’s surface – such as land reclamation and the construction of landfills – made the ground looser and more compressible beneath subsequent buildings.

Some of the motion is also caused by natural processes dating back thousands of years to the most recent ice age. About 24,000 years ago, a huge ice sheet spread across most of New England, and a wall of ice more than a mile high covered what is today Albany in upstate New York. Earth’s mantle, somewhat like a flexed mattress, has been slowly readjusting ever since. New York City, which sits on land that was raised just outside the edge of the ice sheet, is now sinking back down.

The scientists found that on average the metropolitan area subsided by about 0.06 inches (1.6 millimeters) per year – about the same amount that a toenail grows in a month. Using the radars on the ESA (European Space Agency) Sentinel-1 satellites, along with advanced data processing techniques, they mapped the motion in detail and pinpointed neighborhoods and landmarks – down to an airport runway and tennis stadium – that are subsiding more rapidly than the average.

“We’ve produced such a detailed map of vertical land motion in the New York City area that there are features popping out that haven’t been noticed before,” said lead author Brett Buzzanga, a postdoctoral researcher at JPL.

David Bekaert, a JPL scientist and lead investigator of the project, said that tracking local elevation changes and relative sea level can be important for flood mapping and planning purposes. This is especially critical as Earth’s changing climate pushes oceans higher around the world, leading to more frequent nuisance flood events and exacerbating destructive storm surges.

Local Changes

The team identified two notable hot spots of subsidence co-located with landfills in Queens. One, runway 13/31 at LaGuardia Airport, is subsiding at a rate of about 0.15 inches (3.7 millimeters) per year. The scientists noted that the airport is undergoing an $8 billion renovation designed in part to alleviate flooding from the rising waters of the Atlantic Ocean. They also identified Arthur Ashe Stadium, which is sinking at a rate of about 0.18 inches (4.6 millimeters) per year and required construction of a lightweight roof during renovation to reduce its heaviness and amount of subsidence.

Other subsidence hot spots include the southern portion of Governors Island – built on 38 million square feet (3.5 million cubic meters) of rocks and dirt from early 20th century subway excavations – as well as sites near the ocean in Brooklyn’s Coney Island and Arverne by the Sea in Queens that were built on artificial fill. Similar levels of subsidence were observed beneath Route 440 and Interstate 78 in suburban New Jersey, which traverse historic fill locations, and in Rikers Island, expanded to its present size by landfilling.

The scientists also found previously unidentified uplift in East Williamsburg, Brooklyn – rising by about 0.06 inches (1.6 millimeters) per year – and in Woodside, Queens, which rose 0.27 inches (6.9 millimeters) per year between 2016 and 2019 before stabilizing. Co-author Robert Kopp of Rutgers University said that groundwater pumping and injection wells used to treat polluted water may have played a role, but further investigation is needed. “I’m intrigued by the potential of using high-resolution InSAR to measure these kinds of relatively short-lived environmental modifications associated with uplift,” Kopp said.

The scientists said that cities like New York, which are investing in coastal defenses and infrastructure in the face of sea level rise, can benefit from high-resolution estimates of land motion.

The JPL-led OPERA (Observational Products for End-Users from Remote Sensing Analysis) project will detail surface displacement across North America in a future data product. To do that, it will leverage InSAR data from ESA’s Sentinel-1 and from the upcoming NISAR (NASA-Indian Space Research Organization Synthetic Aperture Radar) mission, set to launch in 2024. Information from OPERA will help scientists better monitor vertical land motion along with other changes connected to natural hazards.

News Media Contacts

Jane J. Lee / Andrew Wang
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-0307 / 626-379-6874
jane.j.lee@jpl.nasa.gov / andrew.wang@jpl.nasa.gov

Arctic sea ice likely reached its annual minimum extent on Sept. 19, 2023, making it the sixth-lowest year in the satellite record, according to researchers at NASA and the National Snow and Ice Data Center (NSIDC). Meanwhile, Antarctic sea ice reached its lowest maximum extent on record on Sept. 10 at a time when the ice cover should have been growing at a much faster pace during the darkest and coldest months.

Scientists track the seasonal and annual fluctuations because sea ice shapes Earth’s polar ecosystems and plays a significant role in global climate. Researchers at NSIDC and NASA use satellites to measure sea ice as it melts and refreezes. They track sea ice extent, which is defined as the total area of the ocean in which the ice cover fraction is at least 15%.

Between March and September 2023, the ice cover in the Arctic shrank from a peak area of 5.64 million square miles (14.62 million square kilometers) to 1.63 million square miles (4.23 million square kilometers). That’s roughly 770,000 square miles (1.99 million square kilometers) below the 1981–2010 average minimum of 2.4 million square miles (6.22 million square kilometers). The amount of sea ice lost was enough to cover the entire continental United States.

Sea ice around Antarctica reached its lowest winter maximum extent on Sept. 10, 2023, at 6.5 million square miles (16.96 million square kilometers). That’s 398,000 square miles (1.03 million square kilometers) below the previous record-low reached in 1986 – a difference that equates to roughly the size of Texas and California combined. The average maximum extent between 1981 and 2010 was 7.22 million square miles (18.71 million square kilometers).

“It’s a record-smashing sea ice low in the Antarctic,” said Walt Meier, a sea ice scientist at NSIDC. “Sea ice growth appears low around nearly the whole continent as opposed to any one region.”

This year in the Arctic, scientists saw notably low levels of ice in the Northwest Passage, Meier added. “It is more open there than it used to be. There also seems to be a lot more loose, lower concentration ice – even toward the North Pole – and areas that used to be pretty compact, solid sheets of ice through the summer. That’s been happening more frequently in recent years.”

Meier said the changes are a fundamental, decades-long response to warming temperatures. Since the start of the satellite record for ice in 1979, sea ice has not only been declining in the Arctic, but also getting younger. Earlier starts to spring melting and ever-later starts to autumn freeze-up are leading to longer melting seasons. Research has shown that, averaged across the entire Arctic Ocean, freeze-up is happening about a week later per decade, or one month later than in 1979.

Nathan Kurtz, lab chief of NASA’s Cryospheric Sciences Laboratory at the agency’s Goddard Space Flight Center in Greenbelt, Maryland, said that as the Arctic warms about four times faster than the rest of the planet, the ice is also growing thinner. “Thickness at the end of the growth season largely determines the survivability of sea ice. New research is using satellites like NASA’s ICESat-2 (Ice, Cloud and land Elevation Satellite-2) to monitor how thick the ice is year-round.”

Kurtz said that long-term measurements of sea ice are critical to studying what’s happening in real time at the poles. “At NASA we’re interested in taking cutting-edge measurements, but we’re also trying to connect them to the historical record to better understand what’s driving some of these changes that we’re seeing.”

Scientists are working to understand the cause of the meager growth of the Antarctic sea ice, which could include a combination of factors such as El Nino, wind patterns, and warming ocean temperatures. New research has shown that ocean heat is likely playing an important role in slowing cold season ice growth and enhancing warm season melting.

This record-low extent so far in 2023 is a continuation of a downward trend in Antarctic sea ice that started after a record high in 2014. Prior to 2014, ice surrounding the continent was increasing slightly by about 1% per decade.

Sea ice melting at both poles reinforces warming because of a cycle called “ice-albedo feedback.” While bright sea ice reflects most of the Sun’s energy back to space, open ocean water absorbs 90% of it. With greater areas of the ocean exposed to solar energy, more heat can be absorbed, which warms the ocean waters and further delays sea ice growth.

News Media Contact

Aries Keck
NASA Headquarters
Aries.Keck@nasa.gov

Warm ocean waters from the developing El Niño are shifting north along coastlines in the eastern Pacific Ocean. Along the coast of California, these warm waters are interacting with a persistent marine heat wave that recently influenced the development of Hurricane Hilary. The Surface Water and Ocean Topography (SWOT) satellite is able to spot the movement of these warm ocean waters in unprecedented detail.

A collaboration between NASA and the French space agency, CNES (Centre National d’Études Spatiales), SWOT is measuring the height of nearly all water on Earth’s surface, providing one of the most detailed, comprehensive views yet of the planet’s oceans and fresh water lakes and rivers.

Water expands as it warms, so sea levels tend to be higher in places with warmer water. El Niño – a periodic climate phenomenon that can affect weather patterns around the world – is characterized by higher sea levels and warmer-than-average ocean temperatures along the western coast of the Americas. The image above shows sea surface heights off the U.S. West Coast, near the California-Oregon border, in August. Red and orange indicate higher-than-average ocean heights, while blue and green represent lower-than-average heights.

The SWOT science team made the measurements with the Ka-band Radar Interferometer (KaRIn) instrument. With two antennas spread 33 feet (10 meters) apart on a boom, KaRIn produces a pair of data swaths as it circles the globe, bouncing radar pulses off the water’s surface to collect water-height measurements. The visualization combines data from two passes of the SWOT satellite.

“SWOT’s ability to measure sea surface so close to the coast will be invaluable for researchers but also forecasters looking at things like the development and progress of worldwide phenomena like El Niño,” said Ben Hamlington, a sea level researcher at NASA’s Jet Propulsion Laboratory in Southern California.

Watch Latest Water Satellite Unfold Itself in Space

In its September outlook, the U.S. National Oceanic and Atmospheric Administration forecast a greater than 70% chance for a strong El Niño this coming winter. In addition to warmer water, El Niño is also associated with a weakening of the equatorial trade winds. The phenomenon can bring cooler, wetter conditions to the U.S. Southwest and drought to countries in the western Pacific, such as Indonesia and Australia.

More About the Mission

Launched on Dec. 16, 2022, from Vandenberg Space Force Base in central California, SWOT is now in its operations phase, collecting data that will be used for research and other purposes.

SWOT was jointly developed by NASA and CNES, with contributions from the Canadian Space Agency (CSA) and the UK Space Agency. NASA’s Jet Propulsion Laboratory, which is managed for the agency by Caltech in Pasadena, California, leads the U.S. component of the project. For the flight system payload, NASA provided the KaRIn instrument, a GPS science receiver, a laser retroreflector, a two-beam microwave radiometer, and NASA instrument operations. CNES provided the Doppler Orbitography and Radioposition Integrated by Satellite (DORIS) system, the dual frequency Poseidon altimeter (developed by Thales Alenia Space), the KaRIn radio-frequency subsystem (together with Thales Alenia Space and with support from the UK Space Agency), the satellite platform, and ground operations. CSA provided the KaRIn high-power transmitter assembly. NASA provided the launch vehicle and the agency’s Launch Services Program, based at Kennedy Space Center, managed the associated launch services.

To learn more about SWOT, visit:

https://swot.jpl.nasa.gov/

Summer of 2023 was Earth’s hottest since global records began in 1880, according to scientists at NASA’s Goddard Institute of Space Studies (GISS) in New York.

The months of June, July, and August combined were 0.41 degrees Fahrenheit (0.23 degrees Celsius) warmer than any other summer in NASA’s record, and 2.1 degrees F (1.2 C) warmer than the average summer between 1951 and 1980. August alone was 2.2 F (1.2 C) warmer than the average. June through August is considered meteorological summer in the Northern Hemisphere.

This new record comes as exceptional heat swept across much of the world, exacerbating deadly wildfires in Canada and Hawaii, and searing heat waves in South America, Japan, Europe, and the U.S., while likely contributing to severe rainfall in Italy, Greece, and Central Europe.

“Summer 2023’s record-setting temperatures aren’t just a set of numbers – they result in dire real-world consequences. From sweltering temperatures in Arizona and across the country, to wildfires across Canada, and extreme flooding in Europe and Asia, extreme weather is threatening lives and livelihoods around the world,” said NASA Administrator Bill Nelson. “The impacts of climate change are a threat to our planet and future generations, threats that NASA and the Biden-Harris Administration are tackling head on.”

NASA assembles its temperature record, known as GISTEMP, from surface air temperature data acquired by tens of thousands of meteorological stations, as well as sea surface temperature data from ship- and buoy-based instruments. This raw data is analyzed using methods that account for the varied spacing of temperature stations around the globe and for urban heating effects that could skew the calculations.

The analysis calculates temperature anomalies rather than absolute temperature. A temperature anomaly shows how far the temperature has departed from the 1951 to 1980 base average.

“Exceptionally high sea surface temperatures, fueled in part by the return of El Niño, were largely responsible for the summer’s record warmth,” said Josh Willis, climate scientist and oceanographer at NASA’s Jet Propulsion Laboratory in Southern California.

El Niño is a natural climate phenomenon characterized by warmer than normal sea surface temperatures (and higher sea levels) in the central and eastern tropical Pacific Ocean.

The record-setting summer of 2023 continues a long-term trend of warming. Scientific observations and analyses made over decades by NASA, National Oceanic and Atmospheric Administration (NOAA), and other international institutions have shown this warming has been driven primarily by human-caused greenhouse gas emissions. At the same time, natural El Niño events in the Pacific pump extra warmth into the global atmosphere and often correlate with the warmest years on record.

“With background warming and marine heat waves that have been creeping up on us for decades, this El Niño shot us over the hump for setting all kinds of records,” Willis said. “The heat waves that we experience now are longer, they’re hotter, and they’re more punishing. The atmosphere can also hold more water now, and when it’s hot and humid, it’s even harder for the human body to regulate its temperature.”

Willis and other scientists expect to see the biggest impacts of El Niño in February, March, and April 2024. El Niño is associated with the weakening of easterly trade winds and the movement of warm water from the western Pacific toward the western coast of the Americas. The phenomenon can have widespread effects, often bringing cooler, wetter conditions to the U.S. Southwest and drought to countries in the western Pacific, such as Indonesia and Australia.

“Unfortunately, climate change is happening. Things that we said would come to pass are coming to pass,” said Gavin Schmidt, climate scientist and director of GISS. “And it will get worse if we continue to emit carbon dioxide and other greenhouse gases into our atmosphere.”

NASA’s full temperature data set and the complete methodology used for the temperature calculation and its uncertainties are available online.

GISS is a NASA laboratory managed by the Earth Sciences Division of the agency’s Goddard Space Flight Center in Greenbelt, Maryland. The laboratory is affiliated with Columbia University’s Earth Institute and School of Engineering and Applied Science in New York.

For additional figures and maps related to this announcement, visit:

https://svs.gsfc.nasa.gov/14407

News Media Contacts

Karen Fox/Aries Keck
Headquarters, Washington
202-358-1100
karen.fox@nasa.gov/aries.keck@nasa.gov

Jacob Richmond
Goddard Space Flight Center
301-286-6255
jacob.a.richmond@nasa.gov

A state-of-the-art imaging spectrometer, which will measure the greenhouse gases methane and carbon dioxide from space, moved closer to launch this month after being delivered to a clean room at Planet Labs PBC (Planet) in San Francisco.

Designed and built by NASA’s Jet Propulsion Laboratory in Southern California, this science instrument will be part of an effort led by the nonprofit Carbon Mapper organization to collect data on greenhouse gas point-source emissions. Built around technologies developed for NASA airborne campaigns and space missions, the Carbon Mapper imaging spectrometer will provide targeted data on “super-emitters” – the small percentage of individual sources responsible for a significant fraction of global methane and carbon dioxide emissions.

The Carbon Mapper coalition is a public-private effort led by the Carbon Mapper organization and its partners, including JPL, Planet, the California Air Resources Board, Rocky Mountain Institute, Arizona State University, and the University of Arizona.

The instrument is an advanced imaging spectrometer that measures hundreds of wavelengths of light reflected by Earth’s surface and absorbed by gases in the planet’s atmosphere. Different compounds – including methane and carbon dioxide – absorb different wavelengths of light, leaving a spectral “fingerprint” that the imaging spectrometer can identify. These infrared fingerprints, invisible to the human eye, can pinpoint and quantify strong greenhouse gas emissions and accelerate potential mitigation efforts.

The spectrometer arrived Sept. 12 at Planet, where it will be integrated over the next several months into a Tanager satellite designed by the company. Launch is planned for early 2024.

Before leaving JPL, the spectrometer was put through a series of critical tests to ensure that it could withstand the rigors of launch and the harsh conditions of space. Engineers subjected the spectrometer to intense vibrations similar to what it will endure atop a rocket blasting into orbit, as well as to the extreme temperatures it will experience in the vacuum of space.

There was also an opportunity to use a sample of methane to test the completed instrument while it was in a vacuum chamber at JPL. The test was successful, with the imaging spectrometer producing a clear spectral fingerprint of methane.

“We are thrilled to see the exceptional quality of the methane spectral signature recorded. This bodes well for the space measurement soon to follow,” said Robert Green, the instrument scientist at JPL.

“This delivery is a very exciting step for us as our team can now begin the final stage in satellite integration,” said Jeff Guido, senior director of new missions at Planet. “This milestone is an excellent example of the innovative ways that government, philanthropy, and industry can play to each other’s strengths to build exceptional capability that has the potential for global impact.”

The new satellite is part of a broader effort by Carbon Mapper to survey the globe for point-source emissions of methane and carbon dioxide. That effort includes using measurements provided by an instrument already in orbit: NASA’s Earth Surface Mineral Dust Source Investigation, or EMIT, an imaging spectrometer developed by JPL and installed on the International Space Station. A second imaging spectrometer is being built by Planet in collaboration with JPL. The teams will continue working side by side to deliver these new greenhouse gas measurement capabilities.

More About the Project

Carbon Mapper is a nonprofit organization focused on facilitating timely action to mitigate greenhouse gas emissions. Its mission is to fill gaps in the emerging global ecosystem of methane and carbon dioxide monitoring systems by delivering data at facility scale that is precise, timely, and accessible to empower science-based decision making and action. The organization is leading the development of the Carbon Mapper constellation of satellites supported by a public-private partnership composed of Planet Labs PBC, JPL, the California Air Resources Board, the University of Arizona, Arizona State University, and RMI, with funding from High Tide Foundation, Bloomberg Philanthropies, Grantham Foundation for the Protection of the Environment, and other philanthropic donors.

News Media Contact

Jane J. Lee / Andrew Wang
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-0307 / 626-379-6874
jane.j.lee@jpl.nasa.gov / andrew.wang@jpl.nasa.gov

Kelly Vaughn
Carbon Mapper, Pasadena, Calif.
970-401-0001
kelly@carbonmapper.org