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Two extremes at the same time: Precipitation trends determine how often droughts and heat waves will occur together – Phys.org

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For Central Europe, when using multiple plausible simulations from seven different climate models and assuming different precipitation trends, the frequency of compound hot-dry events varies. In a future ‘dry storyline’, these compound events occur significantly more frequently than in a future ‘wet storyline’. Maps (b) & (c) illustrate this using the example of Central Europe: in the case of the ‘dry storyline’, on average across all simulations, both extremes may occur concurrently at least every four years on average, while in the case of the ‘wet storyline’, it is every ten years. In the historical time period from 1950-1980, compound hot-dry events occurred every 25 years on average. Credit: UFZ

Prolonged droughts and heat waves have negative consequences both for people and the environment. If both of these extreme events occur at the same time, the impacts, in the form of wild fires, tree mortality or crop losses—to name a few examples—can be even more severe. Climate researchers at the Helmholtz Centre for Environmental Research (UFZ) have now discovered that, assuming a global temperature increase of two degrees in the course of global warming, the future frequency of these simultaneously occurring extreme events is primarily determined by local precipitation trends. Understanding this is important, since it enables us to improve our risk adaptation to climate change and our assessment of its consequences, as they write in the journal Nature Climate Change.

The fact that will increase temperatures over land masses, increasing the frequency of droughts and heat waves, is a certainty—as is the fact that will alter the average amount of precipitation on land. However, it has remained unclear until now under what conditions both extreme events will occur together, known as compound hot-dry-events. The UFZ researchers have defined these events as summers in which the average temperature was higher than in 90% of the summers between 1950 and 1980, and precipitation was simultaneously lower than in 90% of those years.

“In the past, periods of drought and heat waves were often considered separately; there is, however, a strong correlation between the two events, which can be seen in the extremes experienced in 2003 and 2018 in Europe. The negative consequences of these compound extremes are often greater than with one single extreme,” says UFZ researcher Dr. Jakob Zscheischler, last author of the study. Until now, however, it was not known what the future simultaneous occurrence of these extremes depends on—the uncertainties in the occurrences estimated via routinely used were too large to arrive at robust pronouncements.

The researchers have now used a novel model ensemble, comprising seven , to reduce and better understand these uncertainties. Each model simulation was carried out up to 100 times in order to account for natural climate variability. They examined the historical period between 1950 and 1980, comparing the results with those of a potential future climate that is two degrees warmer than preindustrial conditions.

“The advantage of these multiple simulations is that we have a much larger volume of data than with conventional model ensembles, enabling us to better estimate compound extremes,” explains Dr. Emanuele Bevacqua, first author and climate researcher at the UFZ. The researchers were able to confirm the previous assumption that the average frequency of compound hot-dry events will increase with global warming: while the frequency lay at 3% between 1950 and 1980, which statistically is an occurrence every 33 years, in a climate that is two degrees warmer, this figure will be around 12%. This would be a four-fold increase compared to the historical period studied.

The were also able to determine from the simulations that the frequency of compound hot-dry events in the future will be determined not by temperature trends, but by precipitation trends. The reason for this is that, even with a moderate warming of two degrees, local temperature increase will be so great that in the future, every drought anywhere in the world will be accompanied by a , regardless of the exact number of degrees by which the temperature increases locally. The uncertainty in the warming leads to an uncertainty in the prediction of compound hot-dry event frequencies of only 1.5%. This discounts temperature as a decisive factor for uncertainty. For precipitation, however, the researchers calculated an uncertainty of up to 48%.

“This demonstrates that local precipitation trends determine whether periods of drought and heat waves will occur simultaneously,” explains Emanuele Bevacqua. For Central Europe, for example, this implies that in the case of a ‘wet storyline’ with increasing precipitation, concurrent droughts and heat waves will occur on average every ten years, whereas in the case of a ‘dry storyline’ with decreasing precipitation, they will occur at least every four years. For Central North America, these events would be expected every nine years (‘wet storyline’) and six years (‘dry storyline’). These regional storylines for precipitation trends can be used as a basis for decisions on adaptation (for example, to evaluate best and worst case-scenarios).

However, even if we know that precipitation trends are decisive for the occurrence of concurrent droughts and heat waves, it is still difficult to predict them any more reliably: “Climate change may shift the distribution of precipitation in certain regions. The pattern of depends on atmospheric circulation, which determines regional weather dynamics through numerous interactions over large parts of the globe,” says Emanuele Bevacqua. Since the dynamic of many of these processes is not yet fully understood, it is difficult to reduce these uncertainties any further.

This finding—that a trend in one variable determines the future occurrence of two simultaneous extreme events with a global temperature increase of two degrees—may also be used for other compound extremes. For example, it can be applied to the interaction of tropical storms and heat waves, or of marine and acidity extremes in the oceans. “In these cases, it is the trend in storm frequency or ocean acidification, respectively, that is the deciding factor which determines the concurrence rates of the two in the future,” says Jakob Zscheischler.


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Global warming intensifies precipitation extremes in China


More information:
Emanuele Bevacqua, Precipitation trends determine future occurrences of compound hot–dry events, Nature Climate Change (2022). DOI: 10.1038/s41558-022-01309-5. www.nature.com/articles/s41558-022-01309-5

Citation:
Two extremes at the same time: Precipitation trends determine how often droughts and heat waves will occur together (2022, March 14)
retrieved 15 March 2022
from https://phys.org/news/2022-03-extremes-precipitation-trends-droughts.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.

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NASA's InSight still hunting marsquakes as power levels diminish – Phys.org

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InSight captured this image of one of its dust-covered solar panels on April 24, 2022, the 1,211th Martian day, or sol, of the mission. Credit: NASA/JPL-Caltech

Dusty solar panels and darker skies are expected to bring the Mars lander mission to a close around the end of this year.

NASA’s InSight Mars lander is gradually losing power and is anticipated to end science operations later this summer. By December, InSight’s team expects the lander to have become inoperative, concluding a mission that has thus far detected more than 1,300 marsquakes—most recently, a magnitude 5 that occurred on May 4—and located quake-prone regions of the Red Planet.

The information gathered from those quakes has allowed scientists to measure the depth and composition of Mars’ crust, mantle, and core. Additionally, InSight (short for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) has recorded invaluable weather data and studied remnants of Mars’ ancient magnetic field.

“InSight has transformed our understanding of the interiors of rocky planets and set the stage for future missions,” said Lori Glaze, director of NASA’s Planetary Science Division. “We can apply what we’ve learned about Mars’ inner structure to Earth, the Moon, Venus, and even rocky planets in other solar systems.”

InSight landed on Mars Nov. 26, 2018. Equipped with a pair of solar panels that each measures about 7 feet (2.2 meters) wide, it was designed to accomplish the mission’s primary science goals in its first Mars year (nearly two Earth years). Having achieved them, the spacecraft is now into an extended mission, and its solar panels have been producing less power as they continue to accumulate dust.

Because of the reduced power, the team will soon put the lander’s robotic arm in its resting position (called the “retirement pose”) for the last time later this month. Originally intended to deploy the seismometer and the lander’s heat probe, the arm has played an unexpected role in the mission: Along with using it to help bury the heat probe after sticky Martian soil presented the probe with challenges, the team used the arm in an innovative way to remove dust from the solar panels. As a result, the seismometer was able to operate more often than it would have otherwise, leading to new discoveries.

[embedded content]

NASA’s InSight Mars lander team speak about the mission’s science and the innovative ways they took on engineering challenges. During its time on Mars, InSight has achieved all its primary science goals and continues to hunt for quakes. Its mission is expected to conclude around the end of 2022. Credit: NASA/JPL-Caltech

When InSight landed, the produced around 5,000 watt-hours each Martian day, or sol—enough to power an electric oven for an hour and 40 minutes. Now, they’re producing roughly 500 watt-hours per sol—enough to power the same electric oven for just 10 minutes.

Additionally, seasonal changes are beginning in Elysium Planitia, InSight’s location on Mars. Over the next few months, there will be more dust in the air, reducing sunlight—and the lander’s energy. While past efforts removed some dust, the mission would need a more powerful dust-cleaning event, such as a “dust devil” (a passing whirlwind), to reverse the current trend.

“We’ve been hoping for a cleaning like we saw happen several times to the Spirit and Opportunity rovers,” said Bruce Banerdt, InSight’s principal investigator at NASA’s Jet Propulsion Laboratory in Southern California, which leads the mission. “That’s still possible, but energy is low enough that our focus is making the most of the science we can still collect.”

If just 25% of InSight’s panels were swept clean by the wind, the lander would gain about 1,000 watt-hours per sol—enough to continue collecting science. However, at the current rate power is declining, InSight’s non-seismic instruments will rarely be turned on after the end of May.

Energy is being prioritized for the lander’s seismometer, which will operate at select times of day, such as at night, when winds are low and marsquakes are easier for the seismometer to “hear.” The seismometer itself is expected to be off by the end of summer, concluding the science phase of the .

At that point, the lander will still have enough power to operate, taking the occasional picture and communicating with Earth. But the team expects that around December, will be low enough that one day InSight will simply stop responding.


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NASA’s InSight records monster quake on Mars


Citation:
NASA’s InSight still hunting marsquakes as power levels diminish (2022, May 17)
retrieved 18 May 2022
from https://phys.org/news/2022-05-nasa-insight-marsquakes-power-diminish.html

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Peek-a-Boo Moon: Astronaut on Space Station Captures Spectacular Photos of the Lunar Eclipse – SciTechDaily

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ESA astronaut Samantha Cristoforetti captured pictures of the May 2022 lunar eclipse from the International Space Station.

On the evening of May 15, 2022, Earth passed between the Sun and the Moon blocking sunlight and casting a shadow on the lunar surface. ESA astronaut Samantha Cristoforetti witnessed this lunar eclipse from the International Space Station and captured it in a series of photographs.

During a lunar eclipse, Earth’s atmosphere scatters sunlight. The blue light from the Sun scatters away, and longer-wavelength red, orange, and yellow light pass through, turning our Moon red.

Lunar Eclipse From International Space Station 1

An image of a lunar eclipse as seen from the International Space Station. Credit: ESA-S.Cristoforetti

In these images, the Moon appears to play hide and seek with one of the International Space Station’s solar panels:

Lunar Eclipse From International Space Station 4

A partially eclipsed Moon playing hide and seek with the solar panel of the International Space Station. Credit: ESA-S.Cristoforetti

Lunar Eclipse From International Space Station 3

A partially eclipsed Moon playing hide and seek with the solar panel of the International Space Station. Credit: ESA-S.Cristoforetti

Lunar Eclipse From International Space Station 2

A partially eclipsed Moon playing hide and seek with the solar panel of the International Space Station. Credit: ESA-S.Cristoforetti

Samantha is living and working aboard the Space Station for her second mission, ‘Minerva’. Learn more about Samantha and the Minerva mission.

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African scientists and technology could drive future black hole discoveries – The Conversation Africa

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Astronomers have revealed the first image of the black hole at the centre of our galaxy, the Milky Way. The image was produced by the Event Horizon Telescope (EHT) Collaboration, an international team made up of over 300 scientists on five continents – including Africa.

Black holes were predicted by Albert Einstein’s General Theory of Relativity over a century ago. They are regions of space so dense that nothing, including light, can escape. Their boundary is known as the event horizon, which marks the point of no return. That’s just one of the reasons these objects are hidden from our eyes. The other is that they are exceedingly small, when placed in their cosmic context. If our Milky Way galaxy were the size of a soccer field, its black hole event horizon would be a million times smaller than a pin prick at centrefield.

How, then, can one photograph them? Our team did so by capturing light from the hot swirling gas in the immediate vicinity of the black hole. This light, with a wavelength of 1 millimetre, is recorded by a global network of antennas that form a single, Earth-sized virtual telescope.

The light looks rather like a ring, a characteristic signature that is the direct consequence of two key processes. First, the black hole is so dense that it bends the path of light near it. Second, it captures light that strays too close to the event horizon. The combined effect produces a so-called black hole shadow – a brightened ring surrounding a distinct deficit of light centred on the black hole. In the case of our Milky Way black hole, this ring has the apparent size of a doughnut on the moon, requiring an extraordinary engineering effort to bring it into focus.




Read more:
How we captured first image of the supermassive black hole at centre of the Milky Way


The unveiling of an image of our black hole, Sagittarius A*, is not just a massive moment for science. It could also be an important catalyst for diversifying African astrophysics research using existing strengths. We were the only two of more than 300 EHT team members based on the African continent. The continent doesn’t host any EHT telescopes – we were brought on board because of expertise we’ve developed in preparation for the world’s largest radio telescope, the Square Kilometre Array (SKA), to be co-hosted by South Africa and Australia.

Why the image is important

This is not the first time a black hole image has captured people’s attention. We were also members of the team that captured the first ever image of a black hole in 2019 (this one is at the centre of a different galaxy, Messier 87, which is 55 million light years away). It has been estimated that more than 4.5 billion people saw that image. Sagittarius A* has also dominated headlines and captured people’s imaginations.

But there’s more to this result than just an incredible image. A plethora of rich scientific results has been described in ten publications by the team. Here are three of our primary highlights.

First, the image is a remarkable validation of Einstein’s General Theory of Relativity. The EHT has now imaged two black holes with masses that differ by a factor of over 1000. Despite the dramatic difference in mass, the measured size and shape are consistent with theoretical predictions.

Second, we have now imaged black holes with very different environments. A wealth of prior research over the past two or three decades shows strong empirical evidence that galaxies and their black holes co-evolve over cosmic time, despite their completely disparate sizes. By zooming into the event horizon of black holes in giant galaxies like M87, as well as more typical galaxies like our own Milky Way, we learn more about how this seemingly implausible relationship between the black hole and its host galaxy plays out.

Third, the image provides us with new insights on the central black hole in our own galactic home. It is the nearest such beast to Earth, so it provides a unique laboratory to understand this interplay – not unlike scrutinising a tree in your own garden to better understand the forests on the distant horizon.

Southern Africa’s geographic advantage

We are proud to be part of the team that produced the first black hole images. In future, we believe South Africa, and the African continent more broadly (including a joint Dutch-Namibian initiative), could play a critical role in making the first black hole movies.




Read more:
Combined power of two telescopes is helping crack the mystery of eerie rings in the sky


As has been the case with the country’s key role in paleoanthropology, there are contributions to global astronomy that can only be made from South African soil. Sagittarius A* lies in the southern sky, passing directly above South Africa. That is a major reason why this image of the Milky Way’s centre, taken by the MeerKAT (a precursor to the SKA) is the best there is.

The MeerKAT Galactic Centre image (top). Predicted snapshot imaging performance (bottom middle), based on a simulated black hole movie (bottom left), using an African-enhanced EHT array (bottom right).
Heywood et al. (2022) / SARAO, M. Johnson (Harvard & Smithsonian)

South Africa also has well-established infrastructure at its astronomical sites, which are protected by legislation. And it has world-class engineers at the forefront of their craft. This makes for low-cost, high-performance telescopes delivered on time and to budget.

New technology is also on our side: a cutting-edge simultaneous multi-frequency receiver design, pioneered by our Korean colleagues, means that EHT sites no longer need to be the most pristine, high-altitude locations on Earth.

All the elements are in place for a dramatic increase in the number of young Africans who participate in this new era of black hole imaging and precision tests of gravity. In the coming years, we hope to be writing about findings that couldn’t have been made without technology on South African soil, as well as African scientists leading high-impact, high-visibility EHT science in synergy with our multi-wavelength astronomy and high-energy astrophysics programmes.

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