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By European Space Agency
Image: This Copernicus Sentinel-2 image captures the intricate blend of natural, rural and urban landscapes around Kunshan, a city in eastern China. View the full article
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By NASA
Earth (ESD)Earth Home Explore Climate Change Science in Action Multimedia Data For Researchers 4 min read
Via NASA Plane, Scientists Find New Gamma-ray Emission in Storm Clouds
Tropical thunderstorm with lightning, near the airport of Santa Marta, Colombia. Credit: Oscar van der Velde There’s more to thunderclouds than rain and lightning. Along with visible light emissions, thunderclouds can produce intense bursts of gamma rays, the most energetic form of light, that last for millionths of a second. The clouds can also glow steadily with gamma rays for seconds to minutes at a time.
Researchers using NASA airborne platforms have now found a new kind of gamma-ray emission that’s shorter in duration than the steady glows and longer than the microsecond bursts. They’re calling it a flickering gamma-ray flash. The discovery fills in a missing link in scientists’ understanding of thundercloud radiation and provides new insights into the mechanisms that produce lightning. The insights, in turn, could lead to more accurate lightning risk estimates for people, aircraft, and spacecraft.
Researchers from the University of Bergen in Norway led the study in collaboration with scientists from NASA’s Marshall Space Flight Center in Huntsville, Alabama, and NASA’s Goddard Space Flight Center in Greenbelt, Maryland, the U.S. Naval Research Laboratory, and multiple universities in the U.S., Mexico, Colombia, and Europe. The findings were described in a pair of papers in Nature, published Oct. 2.
The international research team made their discovery while flying a battery of detectors aboard a NASA ER-2 research aircraft. In July 2023, the ER-2 set out on a series of 10 flights from MacDill Air Force Base in Tampa, Florida. The plane flew figure-eight flight patterns a few miles above tropical thunderclouds in the Caribbean and Central America, providing unprecedented views of cloud activity.
The scientific payload was developed for the Airborne Lightning Observatory for Fly’s Eye Geostationary Lightning Mapper Simulator and Terrestrial Gamma-ray Flashes (ALOFT) campaign. Instrumentation in the payload included weather radars along with multiple sensors for measuring gamma rays, lightning flashes, and microwave emissions from clouds.
NASA’s high-flying ER-2 airplane carries instrumentation in this artist’s impression of the ALOFT mission to record gamma rays (colored purple for illustration) from thunderclouds.Credit: NASA/ALOFT team The researchers had hoped ALOFT instruments would observe fast radiation bursts known as terrestrial gamma-ray flashes (TGFs). The flashes, first discovered in 1992 by NASA’s Compton Gamma Ray Observatory spacecraft, accompany some lightning strikes and last only millionths of a second. Despite their high intensity and their association with visible lightning, few TGFs have been spotted during previous aircraft-based studies.
“I went to a meeting just before the ALOFT campaign,” said principal investigator Nikolai Østgaard, a space physicist with the University of Bergen. “And they asked me: ‘How many TGFs are you going to see?’ I said: ‘Either we’ll see zero, or we’ll see a lot.’ And then we happened to see 130.”
However, the flickering gamma-ray flashes were a complete surprise.
“They’re almost impossible to detect from space,” said co-principal investigator Martino Marisaldi, who is also a University of Bergen space physicist. “But when you are flying at 20 kilometers [12.5 miles] high, you’re so close that you will see them.” The research team found more than 25 of these new flashes, each lasting between 50 to 200 milliseconds.
The abundance of fast bursts and the discovery of intermediate-duration flashes could be among the most important thundercloud discoveries in a decade or more, said University of New Hampshire physicist Joseph Dwyer, who was not involved in the research. “They’re telling us something about how thunderstorms work, which is really important because thunderstorms produce lightning that hurts and kills a lot of people.”
More broadly, Dwyer said he is excited about the prospects of advancing the field of meteorology. “I think everyone assumes that we figured out lightning a long time ago, but it’s an overlooked area … we don’t understand what’s going on inside those clouds right over our heads.” The discovery of flickering gamma-ray flashes may provide crucial clues scientists need to understand thundercloud dynamics, he said.
Turning to aircraft-based instrumentation rather than satellites ensured a lot of bang for research bucks, said the study’s project scientist, Timothy Lang of NASA’s Marshall Space Flight Center in Huntsville, Alabama.
“If we had gotten one flash, we would have been ecstatic — and we got well over 100,” he said. This research could lead to a significant advance in our understanding of thunderstorms and radiation from thunderstorms. “It shows that if you have the right problem and you’re willing to take a little bit of risk, you can have a huge payoff.”
By James Riordon
NASA’s Earth Science News Team
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Last Updated Oct 02, 2024 EditorJenny MarderContactJames RiordonLocationMarshall Space Flight Center Related Terms
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By NASA
5 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Pacific Island nations such as Kiribati — a low-lying country in the southern Pacific Ocean — are preparing now for a future of higher sea levels.NASA Earth Observatory Climate change is rapidly reshaping a region of the world that’s home to millions of people.
In the next 30 years, Pacific Island nations such as Tuvalu, Kiribati, and Fiji will experience at least 8 inches (15 centimeters) of sea level rise, according to an analysis by NASA’s sea level change science team. This amount of rise will occur regardless of whether greenhouse gas emissions change in the coming years.
The sea level change team undertook the analysis of this region at the request of several Pacific Island nations, including Tuvalu and Kiribati, and in close coordination with the U.S. Department of State.
In addition to the overall analysis, the agency’s sea level team produced high-resolution maps showing which areas of different Pacific Island nations will be vulnerable to high-tide flooding — otherwise known as nuisance flooding or sunny day flooding — by the 2050s. Released on Sept. 23, the maps outline flooding potential in a range of emissions scenarios, from best-case to business-as-usual to worst-case.
“Sea level will continue to rise for centuries, causing more frequent flooding,” said Nadya Vinogradova Shiffer, who directs ocean physics programs for NASA’s Earth Science Division. “NASA’s new flood tool tells you what the potential increase in flooding frequency and severity look like in the next decades for the coastal communities of the Pacific Island nations.”
Team members, led by researchers at the University of Hawaii and in collaboration with scientists at the University of Colorado and Virginia Tech, started with flood maps of Kiribati, Tuvalu, Fiji, Nauru, and Niue. They plan to build high-resolution maps for other Pacific Island nations in the near future. The maps can assist Pacific Island nations in deciding where to focus mitigation efforts.
“Science and data can help the community of Tuvalu in relaying accurate sea level rise projections,” said Grace Malie, a youth leader from Tuvalu who is involved with the Rising Nations Initiative, a United Nations-supported program led by Pacific Island nations to help preserve their statehood and protect the rights and heritage of populations affected by climate change. “This will also help with early warning systems, which is something that our country is focusing on at the moment.”
Future Flooding
The analysis by the sea level change team also found that the number of high-tide flooding days in an average year will increase by an order of magnitude for nearly all Pacific Island nations by the 2050s. Portions of the NASA team’s analysis were included in a sea level rise report published by the United Nations in August 2024.
Areas of Tuvalu that currently see less than five high-tide flood days a year could average 25 flood days annually by the 2050s. Regions of Kiribati that see fewer than five flood days a year today will experience an average of 65 flood days annually by the 2050s.
“I am living the reality of climate change,” said Malie. “Everyone (in Tuvalu) lives by the coast or along the coastline, so everyone gets heavily affected by this.”
Flooding on island nations can come from the ocean inundating land during storms or during exceptionally high tides, called king tides. But it can also result when saltwater intrudes into underground areas and pushes the water table to the surface. “There are points on the island where we will see seawater bubbling from beneath the surface and heavily flooding the area,” Malie added.
Matter of Location
Sea level rise doesn’t occur uniformly around the world. A combination of global and local conditions, such as the topography of a coastline and how glacial meltwater is distributed in the ocean, affects the amount of rise a particular region will experience.
“We’re always focused on the differences in sea level rise from one region to another, but in the Pacific, the numbers are surprisingly consistent,” said Ben Hamlington, a sea level researcher at NASA’s Jet Propulsion Laboratory in Southern California and the agency’s sea level change science team lead.
The impacts of 8 inches (15 centimeters) of sea level rise will vary from country to country. For instance, some nations could experience nuisance flooding several times a year at their airport, while others might face frequent neighborhood flooding equivalent to being inundated for nearly half the year.
Researchers would like to combine satellite data on ocean levels with ground-based measurements of sea levels at specific points, as well as with better land elevation information. “But there’s a real lack of on-the-ground data in these countries,” said Hamlington. The combination of space-based and ground-based measurements can yield more precise sea level rise projections and improved understanding of the impacts to countries in the Pacific.
“The future of the young people of Tuvalu is already at stake,” said Malie. “Climate change is more than an environmental crisis. It is about justice, survival for nations like Tuvalu, and global responsibility.”
To explore the high-tide flooding maps for Pacific Island nations, go to:
https://sealevel.nasa.gov
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Jane J. Lee / Andrew Wang
Jet Propulsion Laboratory, Pasadena, Calif.
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Last Updated Sep 25, 2024 Related Terms
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4 min read Arctic Sea Ice Near Historic Low; Antarctic Ice Continues Decline
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By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
This image, taken from a data visualization, shows Arctic sea ice minimum extent on September 11, 2024. The yellow boundary shows the minimum extent averaged over the 30-year period from 1981 to 2010. Download high-resolution video and images from NASA’s Scientific Visualization Studio: https://svsdev.gsfc.nasa.gov/5382NASA’s Scientific Visualization Studio/Trent L. Schindler Arctic sea ice retreated to near-historic lows in the Northern Hemisphere this summer, likely melting to its minimum extent for the year on Sept.11, 2024, according to researchers at NASA and the National Snow and Ice Data Center (NSIDC). The decline continues the decades-long trend of shrinking and thinning ice cover in the Arctic Ocean.
The amount of frozen seawater in the Arctic fluctuates during the year as the ice thaws and regrows between seasons. Scientists chart these swings to construct a picture of how the Arctic responds over time to rising air and sea temperatures and longer melting seasons. Over the past 46 years, satellites have observed persistent trends of more melting in the summer and less ice formation in winter.
This summer, Arctic sea ice decreased to a its minimum extent on September 11, 2024. According to the National Snow and Ice Data Center this is the 7th lowest in the satellite record). The decline continues the long-term trend of shrinking ice cover in the Arctic Ocean.
Credit: NASA’s Goddard Space Flight Center Tracking sea ice changes in real time has revealed wide-ranging impacts, from losses and changes in polar wildlife habitat to impacts on local communities in the Arctic and international trade routes.
This year, Arctic sea ice shrank to a minimal extent of 1.65 million square miles (4.28 million square kilometers). That’s about 750,000 square miles (1.94 million square kilometers) below the 1981 to 2010 end-of-summer average of 2.4 million square miles (6.22 million square kilometers). The difference in ice cover spans an area larger than the state of Alaska. Sea ice extent is defined as the total area of the ocean with at least 15% ice concentration.
Seventh-Lowest in Satellite Record
This year’s minimum remained above the all-time low of 1.31 million square miles (3.39 million square kilometers) set in September 2012. While sea ice coverage can fluctuate from year to year, it has trended downward since the start of the satellite record for ice in the late 1970s. Since then, the loss of sea ice has been about 30,000 square miles (77,800 square kilometers) per year, according to NSIDC.
Scientists currently measure sea ice extent using data from passive microwave sensors aboard satellites in the Defense Meteorological Satellite Program, with additional historical data from the Nimbus-7 satellite, jointly operated by NASA and the National Oceanic and Atmospheric Administration (NOAA).
Today, the overwhelming majority of ice in the Arctic Ocean is thinner, first-year ice, which is less able to survive the warmer months. There is far, far less ice that is three years or older now,
Nathan Kurtz
Chief, NASA's Cryospheric Sciences Laboratory
Sea ice is not only shrinking, it’s getting younger, noted Nathan Kurtz, lab chief of NASA’s Cryospheric Sciences Laboratory at the agency’s Goddard Space Flight Center in Greenbelt, Maryland.
“Today, the overwhelming majority of ice in the Arctic Ocean is thinner, first-year ice, which is less able to survive the warmer months. There is far, far less ice that is three years or older now,” Kurtz said.
Ice thickness measurements collected with spaceborne altimeters, including NASA’s ICESat and ICESat-2 satellites, have found that much of the oldest, thickest ice has already been lost. New research out of NASA’s Jet Propulsion Laboratory in Southern California shows that in the central Arctic, away from the coasts, fall sea ice now hovers around 4.2 feet (1.3 meters) thick, down from a peak of 8.8 feet (2.7 meters) in 1980.
Another Meager Winter Around Antarctica
Sea ice in the southern polar regions of the planet was also low in 2024. Around Antarctica, scientists are tracking near record-low sea ice at a time when it should have been growing extensively during the Southern Hemisphere’s darkest and coldest months.
Ice around the continent is on track to be just over 6.6 million square miles (16.96 million square kilometers). The average maximum extent between 1981 and 2010 was 7.22 million square miles (18.71 million square kilometers).
The meager growth so far in 2024 prolongs a recent downward trend. Prior to 2014, sea ice in the Antarctic was increasing slightly by about 1% per decade. Following a spike in 2014, ice growth has fallen dramatically. Scientists are working to understand the cause of this reversal. The recurring loss hints at a long-term shift in conditions in the Southern Ocean, likely resulting from global climate change.
“While changes in sea ice have been dramatic in the Arctic over several decades, Antarctic sea ice was relatively stable. But that has changed,” said Walt Meier, a sea ice scientist at NSIDC. “It appears that global warming has come to the Southern Ocean.”
In both the Arctic and Antarctic, ice loss compounds ice loss. This is due to the fact that while bright sea ice reflects most of the Sun’s energy back to space, open ocean water absorbs 90% of it. With more of the ocean exposed to sunlight, water temperatures rise, further delaying sea ice growth. This cycle of reinforced warming is called ice-albedo feedback.
Overall, the loss of sea ice increases heat in the Arctic, where temperatures have risen about four times the global average, Kurtz said.
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Sally Younger
Senior Science Writer
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Last Updated Sep 24, 2024 LocationGoddard Space Flight Center Related Terms
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Preparations for Next Moonwalk Simulations Underway (and Underwater)
A Hampton, Virginia, street is flooded by an exceptionally high tide in 2020. Rising seas could make high-tide flooding much more common in coastal communities around the world.Aileen Devlin/Virginia Sea Grant CC BY-ND 2.0 Designed to be user-friendly, the resource contains the latest sea level data, explainers, and other information from several U.S. agencies.
The U.S. Interagency Task Force on Sea Level Change launched the U.S. Sea Level Change website on Monday, Sept. 23. Designed to help communities prepare for rising seas, the site features the latest science on changing sea levels, details about the impact on the environment and coastal communities, and strategies to mitigate the consequences. NASA led the development of the website for the task force.
“NASA, together with our partner agencies, has studied climate change and Earth’s rising seas for decades,” said Karen St. Germain, director of the Earth Science Division at NASA Headquarters in Washington. “The data collected by our satellites and ground-based instruments is crucial to helping policymakers and communities prepare for the consequences of sea level rise. By combining NASA data with information from other federal agencies, the U.S. Sea Level Change website is the latest example of government working for the benefit of humanity.”
Demonstrating a whole-of-government approach, the sea level task force sits within the U.S. Global Change Research Program and includes leading researchers from NASA, the Department of Defense, the Environmental Protection Agency, the Federal Emergency Management Agency, the National Oceanic and Atmospheric Administration (NOAA), the U.S. Agency for International Development, the U.S. Army Corps of Engineers, and the U.S. Geological Survey.
They’ve designed a user-friendly hub that brings together information on sea level change from the various federal agencies. While being detailed and accurate for resource managers, researchers, and others seeking more technical information, the website is intended to be accessible to anyone interested in the latest science and strategies to cope with rising seas.
“Everyone will have access to accurate sea level and flooding information in their favorite U.S. coastal city and see the timing of the projected increase in water levels and flooding frequency,” added Nadya Vinogradova Shiffer, who directs NASA’s sea level change team as well as the ocean physics program at the agency’s headquarters in Washington.
The contributing federal agencies focus on different aspects of sea level rise, including basic scientific research and the effects of rising seas on the environment, as well as infrastructure. With the new site, users can explore the topic from different angles.
“Having this information in one place, delivered in a consistent and authoritative way through a true interagency effort, represents a big step forward for how the federal government helps coastal communities prepare for future sea level rise,” said Ben Hamlington, a sea level researcher at NASA’s Jet Propulsion Laboratory in Southern California.
Site visitors can find explainers on sea level science, summaries of what rising seas will look like for various parts of U.S. coastlines, and updates to the 2022 interagency report on sea level rise. The report concluded that U.S. coastlines will experience an average of 10 to 12 inches (25 to 30 centimeters) of rise above current sea levels by 2050 and that the amount of rise in the next 30 years could equal the total rise seen over the past 100 years.
The report also outlined near-term sea level rise under various levels of greenhouse gas emissions, from best-case to business-as-usual to worst-case scenarios. The scenarios are based on improved scientific understanding of how melting glaciers and ice sheets — as well as upward and downward vertical land motion — will affect ocean heights at our coasts. The data and scenarios have been updated for the task force website.
NASA contributions to the 2022 interagency report, as well as to the newly launched sea level website, are part of ongoing agency work to understand Earth’s rising seas. NASA’s efforts to monitor the ocean span more than 30 years and include satellites such as Sentinel-6 Michael Freilich and the Surface Water and Ocean Topography (SWOT) mission. Both were jointly developed by the agency and international and domestic partners. Agency partners on Sentinel-6 Michael Freilich include ESA (European Space Agency), the European Organisation for the Exploitation of Meteorological Satellites, and NOAA. For SWOT, NASA partners include the French space agency CNES (Centre National d’Études Spatiales), CSA (the Canadian Space Agency), and the UK Space Agency.
For more on how NASA studies our home planet, see:
http://www.nasa.gov/earth
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Elizabeth Vlock / Aries Keck
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202-358-1600 / 202-604-2356
elizabeth.a.vlock@nasa.gov / aries.keck@nasa.gov
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
2024-127
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Last Updated Sep 24, 2024 Related Terms
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