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    • By European Space Agency
      Global warming is driving the rapid melting of the Greenland Ice Sheet, contributing to global sea level rise and disrupting weather patterns worldwide. Because of this, precise measurements of its changing shape are of critical importance for adapting to climate change.
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    • By NASA
      5 min read
      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      Data from the SWOT satellite was used to calculate average water levels for lakes and reservoirs in the Ohio River Basin from July 2023 to November 2024. Yellow indicates values greater than 1,600 feet (500 meters) above sea level; dark purple represents water levels less than 330 feet (100 meters). Data from the U.S.-European Surface Water and Ocean Topography mission gives researchers a detailed look at lakes and reservoirs in a U.S. watershed.
      The Ohio River Basin stretches from Pennsylvania to Illinois and contains a system of reservoirs, lakes, and rivers that drains an area almost as large as France. Researchers with the SWOT (Surface Water and Ocean Topography) mission, a collaboration between NASA and the French space agency CNES (Centre National d’Études Spatiales), now have a new tool for measuring water levels not only in this area, which is home to more than 25 million people, but in other watersheds around the world as well.
      Since early 2023, SWOT has been measuring the height of nearly all water on Earth’s surface — including oceans, lakes, reservoirs, and rivers — covering nearly the entire globe at least once every 21 days. The SWOT satellite also measures the horizontal extent of water in freshwater bodies. Earlier this year, the mission started making validated data publicly available.
      “Having these two perspectives — water extent and levels — at the same time, along with detailed, frequent coverage over large areas, is unprecedented,” said Jida Wang, a hydrologist at the University of Illinois Urbana-Champaign and a member of the SWOT science team. “This is a groundbreaking, exciting aspect of SWOT.”
      Researchers can use the mission’s data on water level and extent to calculate how the amount of water stored in a lake or reservoir changes over time. This, in turn, can give hydrologists a more precise picture of river discharge — how much water moves through a particular stretch of river.
      The visualization above uses SWOT data from July 2023 to November 2024 to show the average water level above sea level in lakes and reservoirs in the Ohio River Basin, which drains into the Mississippi River. Yellow indicates values greater than 1,600 feet (500 meters), and dark purple represents water levels less than 330 feet (100 meters). Comparing how such levels change can help hydrologists measure water availability over time in a local area or across a watershed.
      Complementing a Patchwork of Data
      Historically, estimating freshwater availability for communities within a river basin has been challenging. Researchers gather information from gauges installed at certain lakes and reservoirs, from airborne surveys, and from other satellites that look at either water level or extent. But for ground-based and airborne instruments, the coverage can be limited in space and time. Hydrologists can piece together some of what they need from different satellites, but the data may or may not have been taken at the same time, or the researchers might still need to augment the information with measurements from ground-based sensors.
      Even then, calculating freshwater availability can be complicated. Much of the work relies on computer models. “Traditional water models often don’t work very well in highly regulated basins like the Ohio because they have trouble representing the unpredictable behavior of dam operations,” said George Allen, a freshwater researcher at Virginia Tech in Blacksburg and a member of the SWOT science team.
      Many river basins in the United States include dams and reservoirs managed by a patchwork of entities. While the people who manage a reservoir may know how their section of water behaves, planning for water availability down the entire length of a river can be a challenge. Since SWOT looks at both rivers and lakes, its data can help provide a more unified view.
      “The data lets water managers really know what other people in these freshwater systems are doing,” said SWOT science team member Colin Gleason, a hydrologist at the University of Massachusetts Amherst.
      While SWOT researchers are excited about the possibilities that the data is opening up, there is still much to be done. The satellite’s high-resolution view of water levels and extent means there is a vast ocean of data that researchers must wade through, and it will take some time to process and analyze the measurements.
      More About SWOT
       The SWOT satellite 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, 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 Ka-band radar interferometer (KaRIn) instrument, a GPS science receiver, a laser retroreflector, a two-beam microwave radiometer, and NASA instrument operations.  The Doppler Orbitography and Radioposition Integrated by Satellite 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 were provided by CNES. The KaRIn high-power transmitter assembly was provided by CSA.
      To learn more about SWOT, visit:
      https://swot.jpl.nasa.gov
      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
      2024-176
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      Details
      Last Updated Dec 17, 2024 Related Terms
      SWOT (Surface Water and Ocean Topography) Jet Propulsion Laboratory Water on Earth Explore More
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    • By European Space Agency
      Video: 00:04:04 English Paxi explores ice
      Join Paxi on an adventure to the North and South poles, to learn more about ice and its role in keeping Earth cool.
       
      Italian Paxi osserva il ghiaccio
      Unisciti a Paxi in un'avventura ai poli Nord e Sud, per saperne di più sul ghiaccio e sul suo ruolo nel mantenere la Terra fresca.
       
      German Paxi erforscht das Eis
      Begleiten Sie Paxi auf ein Abenteuer zum Nord- und Südpol, um mehr über Eis und seine Rolle bei der Kühlung der Erde zu erfahren.
       
      French Paxi explore la glace
      Rejoignez Paxi dans une aventure aux pôles Nord et Sud, pour en savoir plus sur la glace et son rôle dans le refroidissement de la Terre.
       
      Spanish Paxi explora el hielo
      Únete a Paxi en una aventura a los polos Norte y Sur, para aprender más sobre el hielo y su papel en mantener la Tierra fría.
       
      Portuguese Paxi explora o gelo
      Junte-se a Paxi numa aventura aos pólos Norte e Sul, para aprender mais sobre o gelo e o seu papel na manutenção da Terra fresca.
       
      Greek Ο Πάξι εξερευνά τον πάγο
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    • By NASA
      The Fresh Eyes on Ice team receives the C. Peter Magrath exemplary project award from the Association of Public and Land-grant Universities. H. Buurman Congratulations to the Fresh Eyes on Ice project, which received a C. Peter Magrath exemplary project award from the Association of Public and Land-grant Universities! The award recognizes programs that demonstrate how colleges and universities have redesigned their learning, discovery, and engagement missions to deepen their partnerships and achieve broader impacts in their communities.
      “Thank you to all of you for making this project what it is.” said Fresh Eyes on Ice project lead Research Professor Katie Spellman from the University of Alaska, Fairbanks. “We couldn’t do it without you.”
      Fresh Eyes on Ice tracks changes in the timing and thickness of ice throughout Alaska and the circumpolar north. You can get involved by downloading the GLOBE Observer app and taking photos of ice conditions using the GLOBE Land Cover protocol.
      Fresh Eyes on Ice is supported by the Navigating the New Arctic Program of the U.S. National Science Foundation and the NASA Citizen Science for Earth Systems Program.
      Facebook logo @DoNASAScience @DoNASAScience Share








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    • By NASA
      Scientists find that cometary dust affects interpretation of spacecraft measurements, reopening the case for comets like 67P as potential sources of water for early Earth. 
      Researchers have found that water on Comet 67P/Churyumov–Gerasimenko has a similar molecular signature to the water in Earth’s oceans. Contradicting some recent results, this finding reopens the case that Jupiter-family comets like 67P could have helped deliver water to Earth.  
      Water was essential for life to form and flourish on Earth and it remains central for Earth life today. While some water likely existed in the gas and dust from which our planet materialized around 4.6 billion years ago, much of the water would have vaporized because Earth formed close to the Sun’s intense heat. How Earth ultimately became rich in liquid water has remained a source of debate for scientists.
      Research has shown that some of Earth’s water originated through vapor vented from volcanoes; that vapor condensed and rained down on the oceans. But scientists have found evidence that a substantial portion of our oceans came from the ice and minerals on asteroids, and possibly comets, that crashed into Earth. A wave of comet and asteroid collisions with the solar system’s inner planets 4 billion years ago would have made this possible.   
      This image, taken by ESA’s Rosetta navigation camera, was taken from a about 53 miles from the center of Comet 67P/Churyumov-Gerasimenko on March 14, 2015. The image resolution is 24 feet per pixel and is cropped and processed to bring out the details of the comet’s activity. ESA/Rosetta/NAVCAM While the case connecting asteroid water to Earth’s is strong, the role of comets has puzzled scientists. Several measurements of Jupiter-family comets — which contain primitive material from the early solar system and are thought to have formed beyond the orbit of Saturn — showed a strong link between their water and Earth’s. This link was based on a key molecular signature scientists use to trace the origin of water across the solar system.
      This signature is the ratio of deuterium (D) to regular hydrogen (H) in the water of any object, and it gives scientists clues about where that object formed. Deuterium is a rare, heavier type — or isotope — of hydrogen. When compared to Earth’s water, this hydrogen ratio in comets and asteroids can reveal whether there’s a connection.  
      Because water with deuterium is more likely to form in cold environments, there’s a higher concentration of the isotope on objects that formed far from the Sun, such as comets, than in objects that formed closer to the Sun, like asteroids. 
      Measurements within the last couple of decades of deuterium in the water vapor of several other Jupiter-family comets showed similar levels to Earth’s water. 
      “It was really starting to look like these comets played a major role in delivering water to Earth,” said Kathleen Mandt, planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Mandt led the research, published in Science Advances on Nov. 13, that revises the abundance of deuterium in 67P. 

      About Kathleen Mandt

      But in 2014, ESA’s (European Space Agency) Rosetta mission to 67P challenged the idea that Jupiter-family comets helped fill Earth’s water reservoir. Scientists who analyzed Rosetta’s water measurements found the highest concentration of deuterium of any comet, and about three times more deuterium than there is in Earth’s oceans, which have about 1 deuterium atom for every 6,420 hydrogen atoms.  
      “It was a big surprise and it made us rethink everything,” Mandt said.  
      Mandt’s team decided to use an advanced statistical-computation technique to automate the laborious process of isolating deuterium-rich  water in more than 16,000 Rosetta measurements. Rosetta made these measurements in the “coma” of gas and dust surrounding 67P. Mandt’s team, which included Rosetta scientists, was the first to analyze all of the European mission’s water measurements spanning the entire mission. 
      The researchers wanted to understand what physical processes caused the variability in the hydrogen isotope ratios measured at comets. Lab studies and comet observations showed that cometary dust could affect the readings of the hydrogen ratio that scientists detect in comet vapor, which could change our understanding of where comet water comes from and how it compares to Earth’s water. 
      What are comets made of? It’s one of the questions ESA’s Rosetta mission to comet 67P/Churyumov-Gerasimenko wanted to answer. “So I was just curious if we could find evidence for that happening at 67P,” Mandt said. “And this is just one of those very rare cases where you propose a hypothesis and actually find it happening.” 
      Indeed, Mandt’s team found a clear connection between deuterium measurements in the coma of 67P and the amount of dust around the Rosetta spacecraft, showing that the measurements taken near the spacecraft in some parts of the coma may not be representative of the composition of a comet’s body.  
      As a comet moves in its orbit closer to the Sun, its surface warms up, causing gas to release from the surface, including dust with bits of water ice on it. Water with deuterium sticks to dust grains more readily than regular water does, research suggests. When the ice on these dust grains is released into the coma, this effect could make the comet appear to have more deuterium than it has.  
      Mandt and her team reported that by the time dust gets to the outer part of the coma, at least 75 miles from the comet body, it is dried out. With the deuterium-rich water gone, a spacecraft can accurately measure the amount of deuterium coming from the comet body.
      This finding, the paper authors say, has big implications not only for understanding comets’ role in delivering Earth’s water, but also for understanding comet observations that provide insight into the formation of the early solar system.  
      “This means there is a great opportunity to revisit our past observations and prepare for future ones so we can better account for the dust effects,” Mandt said. 
      By Lonnie Shekhtman
      NASA’s Goddard Space Flight Center, Greenbelt, Md.
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      Details
      Last Updated Dec 03, 2024 Editor Lonnie Shekhtman Contact Lonnie Shekhtman lonnie.shekhtman@nasa.gov Location Goddard Space Flight Center Related Terms
      Comets Goddard Space Flight Center Planetary Science Planetary Science Division Rosetta Science Mission Directorate The Solar System View the full article
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