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Satellites monitor Mount Etna’s unpredictable behaviour
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By USH
A rare and intriguing phenomenon has been observed in China. On the night of October 27th, Chinese astrophotographer Shengyu Li set up his camera to capture star trails over Mount Xiannairi in Sichuan Province. To his surprise, he recorded mysterious blue flashes accompanying an avalanche.
The exact cause of these "blue lights" remains unclear, sparking various theories. Some speculate they could stem from geomagnetic activity, interactions of cosmic rays in the upper atmosphere, or rare atmospheric phenomena like blue jets or elves. However, Li offers another explanation: the flashes might result from triboluminescence—light produced by friction during ice fragmentation.
Triboluminescence occurs when certain materials emit light as they are fractured, scratched, or rubbed. This phenomenon happens due to the breaking of chemical bonds or the sudden separation of surfaces, which generates electrical charges. These charges can ionize the surrounding air or excite the material itself, creating visible light.
The hypothesis suggests that this event could be an example of triboluminescence. However, it also raises the intriguing possibility of a connection to UFO phenomena, such as orbs or other unexplained lights that have been observed around the world over the years.
Hypothesis: The sighting depicts what appears to be a blue light descending onto a snowbank, following the avalanche as it moves downward, and then vanishing before seemingly ascending again.
Did the avalanche trigger the blue light, or did the blue light crash into the snow, causing the avalanche?
Whether this phenomenon is a rare case of triboluminescence, potentially the first instance of it being captured on camera or something linked to unexplained UFO activity, the recording of this light remains a unique and fascinating occurrence. View the full article
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By NASA
3 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
The focus of Airspace Technology Demonstration 2 was IADS, a software that coordinates flight schedules between the ramp, tower, terminal, and center control facilities. This visual representation of data helps minimize delays on the ground.NASA / Jim Banke If every commuter drove the same few roads at the same time every day, the traffic would be unbearable. That’s exactly what’s happening in the skies above the nation, known as national airspace (NAS). Multiple flights from different airlines try to use the most direct flight paths, converging on the same airports. With limited runway space, that causes jumbo-sized traffic congestion.
“The majority of uncertainty in the NAS can be attributed to surface operations, and in particular, uncertainty related to when a flight will be available to push back from the gate,” said Jeremy Coupe of NASA’s Ames Research Center in Silicon Valley, California. To help develop a solution, NASA Ames focused on how to improve managing traffic on the ground and scheduling departures.
Holding airplanes at the gate until just before takeoff allows them to run on power supplied by the airport. American Airlines saved millions of gallons of fuel and maintenance costs and tons of harmful emissions by only running engines when arriving at and leaving the gate.NASA Working with the Federal Aviation Administration (FAA), commercial airlines, and airports, NASA developed and tested a new program to manage airport traffic on the ground – the Integrated Arrival, Departure, and Surface (IADS) system. In 2022, the FAA began incorporating this system’s capabilities at 27 of the busiest airports in the country.
Just as a traffic officer can prevent gridlock at a busy intersection, IADS is designed to prevent similar traffic tangles. The first test site for the program development was Charlotte Douglas International Airport in North Carolina, the second-busiest airport on the East Coast with only three runways. About 75% of those are connecting flights.
Before IADS, one challenge the airport faced was a technology mismatch – the airport’s control tower used one software program and ground management used a different one, with no way to integrate them. A phone call was the most common way to notify each other about changes or problems. With approximately 115 aircraft on the ground at any time, a delay in communication could create complications. A plane leaving the gate before being notified of a delay could result in several planes waiting in line at the runway.
“Knowing that you’re going to get where you need to go when the airline says it’s going to deliver you is what people stress about when they’re traveling, especially if they’re trying to make connections in an airport like Charlotte,” said Lee Davis, communications director for the airport. Many factors, including weather, influence timeliness, but making ground operations run predictably is fundamental.
With near real-time data related to on-time departures and delays, airlines can actively address issues related to connections for crew, customers, and cargo. Whether it’s in space or the skies above, NASA innovations continue to make travel more efficient.
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Last Updated Nov 27, 2024 Related Terms
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By NASA
4 min read
NASA Satellites Reveal Abrupt Drop in Global Freshwater Levels
Earth (ESD) Earth Home Explore Climate Change Science in Action Multimedia Data For Researchers GRACE satellites measure gravity as they orbit the planet to reveal shifting levels of water on the Earth (artist’s concept). NASA/JPL-Caltech An international team of scientists using observations from NASA-German satellites found evidence that Earth’s total amount of freshwater dropped abruptly starting in May 2014 and has remained low ever since. Reporting in Surveys in Geophysics, the researchers suggested the shift could indicate Earth’s continents have entered a persistently drier phase.
From 2015 through 2023, satellite measurements showed that the average amount of freshwater stored on land — that includes liquid surface water like lakes and rivers, plus water in aquifers underground — was 290 cubic miles (1,200 cubic km) lower than the average levels from 2002 through 2014, said Matthew Rodell, one of the study authors and a hydrologist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “That’s two and a half times the volume of Lake Erie lost.”
During times of drought, along with the modern expansion of irrigated agriculture, farms and cities must rely more heavily on groundwater, which can lead to a cycle of declining underground water supplies: freshwater supplies become depleted, rain and snow fail to replenish them, and more groundwater is pumped. The reduction in available water puts a strain on farmers and communities, potentially leading to famine, conflicts, poverty, and an increased risk of disease when people turn to contaminated water sources, according to a UN report on water stress published in 2024.
The team of researchers identified this abrupt, global decrease in freshwater using observations from the Gravity Recovery and Climate Experiment (GRACE) satellites, operated by the German Aerospace Center, German Research Centre for Geosciences, and NASA. GRACE satellites measure fluctuations in Earth’s gravity on monthly scales that reveal changes in the mass of water on and under the ground. The original GRACE satellites flew from March 2002 to October 2017. The successor GRACE–Follow On (GRACE–FO) satellites launched in May 2018.
This map shows the years that terrestrial water storage hit a 22-year minimum (i.e., the land was driest) at each location, based on data from the GRACE and GRACE/FO satellites. A significantly large portion of the global land surface reached this minimum in the nine years since 2015, which happen to be the nine warmest years in the modern temperature record. Image by NASA Earth Observatory/Wanmei Liang with data courtesy of Mary Michael O’Neill The decline in global freshwater reported in the study began with a massive drought in northern and central Brazil, and was followed shortly by a series of major droughts in Australasia, South America, North America, Europe, and Africa. Warmer ocean temperatures in the tropical Pacific from late 2014 into 2016, culminating in one of the most significant El Niño events since 1950, led to shifts in atmospheric jet streams that altered weather and rainfall patterns around the world. However, even after El Niño subsided, global freshwater failed to rebound. In fact, Rodell and team report that 13 of the world’s 30 most intense droughts observed by GRACE occurred since January 2015. Rodell and colleagues suspect that global warming might be contributing to the enduring freshwater depletion.
Global warming leads the atmosphere to hold more water vapor, which results in more extreme precipitation, said NASA Goddard meteorologist Michael Bosilovich. While total annual rain and snowfall levels may not change dramatically, long periods between intense precipitation events allow the soil to dry and become more compact. That decreases the amount of water the ground can absorb when it does rain.
“The problem when you have extreme precipitation,” Bosilovich said, “is the water ends up running off,” instead of soaking in and replenishing groundwater stores. Globally, freshwater levels have stayed consistently low since the 2014-2016 El Niño, while more water remains trapped in the atmosphere as water vapor. “Warming temperatures increase both the evaporation of water from the surface to the atmosphere, and the water-holding capacity of the atmosphere, increasing the frequency and intensity of drought conditions,” he noted.
While there are reasons to suspect that the abrupt drop in freshwater is largely due to global warming, it can be difficult to definitively link the two, said Susanna Werth, a hydrologist and remote sensing scientist at Virginia Tech, who was not affiliated with the study. “There are uncertainties in climate predictions,” Werth said. “Measurements and models always come with errors.”
It remains to be seen whether global freshwater will rebound to pre-2015 values, hold steady, or resume its decline. Considering that the nine warmest years in the modern temperature record coincided with the abrupt freshwater decline, Rodell said, “We don’t think this is a coincidence, and it could be a harbinger of what’s to come.”
By James R. Riordon
NASA’s Earth Science News Team
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Last Updated Nov 15, 2024 Editor James Riordon Contact James Riordon james.r.riordon@nasa.gov Location NASA Goddard Space Flight Center Related Terms
Earth Goddard Space Flight Center GRACE (Gravity Recovery And Climate Experiment) GRACE-FO (Gravity Recovery and Climate Experiment Follow-on) Water on Earth Explore More
4 min read NASA Satellites Find Snow Didn’t Offset Southwest US Groundwater Loss
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By European Space Agency
Torrential rainfall causing deadly flash floods has hit southern and eastern Spain in regions including the Costa del Sol, where the city of Malaga is located, and Valencia in the east. As these areas struggle to cope with the aftermath, satellite technology has played a crucial role in assessing the damages of the affected areas.
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