Tag Archives: plume

Australia’s wildfires created a ‘record-breaking’ smoke plume in the upper atmosphere

Australia’s bushfires set a record for the largest smoke cloud generated by a wildfire, a new paper reports. The plume was at least three times larger than any previously recorded one.

Image credits Terri Sharp.

Researchers at the University of Saskatchewan’s (USask) Institute of Space and Atmospheric Studies say that last winter’s Australian wildfires created a smoke cloud that pushed all the way to the stratosphere, some 35 kilometers above the surface, and reached incredible sizes. At its largest, it measured 1,000 kilometers across. The cloud remained intact for three months and traveled over 66,000 kilometers.

King smoke

“When I saw the satellite measurement of the smoke plume at 35 kilometres, it was jaw dropping. I never would have expected that,” said Adam Bourassa, professor of physics and engineering physics, who led the USask group which played a key role in analyzing NASA satellite data.

The fires seen in Australia this year were so devastating that the summer of 2020 has been nicknamed the “Black Summer“. It’s an apt name — the blazes claimed over 5.8 million hectares of forest in the continent’s southeast and bellowed massive amounts of smoke.

An international research team led by Sergey Khaykin from Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS) in France. The findings, they hope, will help us better understand how wildfires interact with and affect our planet’s atmosphere.

“We’re seeing records broken in terms of the impact on the atmosphere from these fires,” said Bourassa. “Knowing that they’re likely to strike more frequently and with more intensity due to climate change, we could end up with a pretty dramatically changed atmosphere.”

Bourassa’s team has experience in a specific type of satellite measurement that can pick up on smoke in the upper layers of the atmosphere. He explains that wildfires such as those in Australia and Western Canada (in 2017, the world’s second-largest to date) got so big that they generated their own clouds, Pyrocumulonimbus, and their own thunderstorms.

These thunderstorms create powerful updrafts that propel smoke and air all the way to the stratosphere, which is higher than the altitudes that commercial jets typically fly at.

The team used a satellite-mounted device called a spectrometer to analyze the plumes. In essence, they measured how much sunlight was scattered (reflected) from the atmosphere back to the satellite, which gave them a detailed layer-by-layer look at the atmosphere.

One finding, that Bourassa calls “amazing” is that this smoke starts absorbing sunlight and heating up. When it gets hot enough, it starts “to rise in a swirling vortex ‘bubble’, and it just rose and rose higher and higher through the atmosphere.”

Another finding was that the smoke from Australia’s wildfires blocked sunlight from reaching the surface to an extent never seen before. The issue was compounded by the fact that the stratosphere is typically quite stable, meaning aerosol particles such as those in smoke can remain in suspension here for months on end, having a disproportionately-high effect on climate.

The paper “The 2019/20 Australian wildfires generated a persistent smoke-charged vortex rising up to 35 km altitude” has been published in the journal Communications Earth & Environment.

Staghorn coral.

Miami dredging caused “extensive coral mortality and critical habitat loss” for the US’ only continental reef

Researchers at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science say that local reefs have suffered extensive damage from sediment plumes stirred up by the 16-month dredging operation at the Port of Miami.

Sediment plume.

Natural sediment plumes from the Mississippi River (right) and the Atchafalaya River (left).
Image credits NASA.

The team estimates that over half a million corals were killed — those that lived within 550 yards (500 meters) of the dredged channel. Dredging operations, which involve clearing the seabed by scooping out mud, weeds, and rubbish with a dredge, seem to have impacted more than 15 miles (25 kilometers) of Florida’s reef tract, resulting in widespread coral death.

Deadly dredging

“Coral reefs worldwide are facing severe declines from climate change,” said Andrew Baker, associate professor of marine biology and ecology at the UM Rosenstiel School and senior author of the study. “If we want to conserve these ecosystems for the generations that come after us, it’s essential that we do all we can to conserve the corals we still have left.”

“These climate survivors may hold the key to understanding how some corals can survive global changes. We have to start locally by doing all we can to protect our remaining corals from impacts, like dredging, that we have the ability to control or prevent.”

Dredging operations at the Port of Miami began in 2013 as part of a larger construction effort in the area. The team analyzed data that was originally collected by consultants as part of the dredge’s environmental monitoring program. This program did note the loss of coral in the area but wrote it off as the consequence of a coral disease that was making a region-wide outbreak at the same time.

The present research ruled out disease by controlling for its impacts: the team looked at losses in coral species that were known to be immune to the outbreak. They tested whether corals closer to the dredge site were more likely to die during the dredging period than those further away. Most of the documented coral losses near the Port of Miami were the result of dredging, the team found.

Staghorn coral.

Staghorn coral, a species of coral in the Florida Reef.
Image via Wikimedia.

“It was important to differentiate these multiple impacts occurring on the reefs to understand the direct effects of dredging specifically,” said lead author Ross Cunning, who began the project while a postdoctoral scientist at the UM Rosenstiel School and is now a research biologist at the Shedd Aquarium in Chicago.

“We brought together all the available data from satellites, sediment traps, and hundreds of underwater surveys. Together, the multiple, independent datasets clearly show that dredging caused the major damages observed on these reefs.”

The team also looked at sediment plumes, which are clouds of suspended sediment stirred up by the dredges — the team reports they’re big enough to be seen from space — and whether they could predict the damage observed on the reefs below. It turns out that they could; the team says that the satellite-tracked plumes had a very high correlation with coral death on the seafloor. This is the first study to show that satellite data can be reliably used to predict dredging impacts on corals and their habitats.

“This connection allowed us to predict impacts beyond where ship-based monitoring was taking place, and showed that dredging likely damaged this reef several kilometers away,” said study co-author Brian Barnes of the University of South Florida.

“While this same relationship may not apply in all projects, this is a remarkable finding that further establishes Earth-observing satellites as independent monitoring tools to fill in gaps where data are otherwise not available.”

Rachel Silverstein, executive director and waterkeeper of Miami Waterkeeper and a co-author of the study says the study uncovered a “devastating story of loss that we cannot afford to ignore any longer.” She hopes that the team’s findings can be used to guide restoration efforts and to prevent similar tragedies in the future.

Florida can boast the only nearshore reef in the continental United States, but its coral cover has declined by at least 70% since the 1970s, the team explains. Some species in this reef — Staghorn corals (Acropora cervicornis), which were once common in shallow water and have declined by an estimated 98% — are now listed as threatened under the Endangered Species Act. The sites directly adjacent to the dredge site have been designated as “critical habitat” for the staghorn corals.

The paper “Extensive coral mortality and critical habitat loss following dredging and their association with remotely-sensed sediment plumes,” has been published in the journal Marine Pollution Bulletin.

Enceladus interior.

Enceladus “the only body besides Earth to satisfy all of the basic requirements for life,” Cassini reveals

Data beamed back by the Cassini spacecraft reveals that Enceladus, Saturn’s sixth-largest moon, isn’t shy about blasting large organic molecules into space.

Enceladus interior.

Hydrothermal processes in the moon’s rocky core could synthesize organics from inorganic precursors. Alternatively, these processes could be transforming preexisting organics by heating, or they could even generate geochemical conditions in the subsurface ocean of Enceladus that would allow possible forms of alien life to synthesize biological molecules.
Image credits NASA/JPL-Caltech/Space Science Institute/LPG-CNRS/Nantes-Angers/ESA

Mass spectrometry readings beamed back by NASA’s Cassini craft show that Enceladus is bursting with organic molecules. The moon’s icy surface is pockmarked with deep cracks that spew complex, carbon-rich compounds into space. Scientists at the Southwest Research Institute (SwRI) say these compounds are likely the result of interactions between the moon’s rocky core and warm waters from its subsurface ocean.

Why so organic?

“We are, yet again, blown away by Enceladus,” said SwRI’s Dr. Christopher Glein, co-author of a paper describin the discovery.

“Now we’ve found organic molecules with masses above 200 atomic mass units. That’s over ten times heavier than methane. With complex organic molecules emanating from its liquid water ocean, this moon is the only body besides Earth known to simultaneously satisfy all of the basic requirements for life as we know it.”

The Cassini mission, a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency, is widely-held to be one of the most ambitious space exploration missions we’ve ever embarked upon. Launched on October 15, 1997, Cassini spent some 13 years studying the gas giant and its moons. The craft also flew by Venus (April 1998 and July 1999), Earth (August 1999), the asteroid 2685 Masursky, and Jupiter (December 2000), before settling in on Saturn’s orbit on July 1st, 2001.

Enceladus. Image credits: NASA/JPL.

On September 15, 2017, NASA de-commissioned the aging craft with a bang: they deorbited Cassini, letting it fall towards Saturn’s core and burn up in its atmosphere.

However, the wealth of information this tiny craft beamed back from its travels is still giving astronomers a lot to work on. Before its fiery demise, Cassini sampled the plume material ejected from the subsurface of Enceladus. Using its Cosmic Dust Analyzer (CDA) and the SwRI-led Ion and Neutral Mass Spectrometer (INMS) instruments, the craft analyzed both the plume itself and Saturn’s E-ring — which is formed by ice grains from the plumes trapped in Saturn’s gravity well.

Chemicals Enceladus.

Synthesis path of different aromatic cations identified in Enceladus’ plume.
Image credits F. Postberg et al., 2018, Nature.

During one of Cassini’s particularly close flybys of Enceladus (Oct. 28, 2015), the INMS detected molecular hydrogen in the moon’s plume ejections. Previous flybys also revealed the presence of a global subsurface ocean and a rocky core. This was the first indication that the moon can boast active geochemical below the surface, most likely between water and rocks in hydrothermal vents.

The presence of hydrogen was also grounds for great enthusiasm at NASA — the element is a known source of chemical energy for microbes living in hydrothermal vents here on good ol’ Earth.

“Once you have identified a potential food source for microbes, the next question to ask is ‘what is the nature of the complex organics in the ocean?'” says SwRI’s Dr. Hunter Waite, INMS principal investigator and paper coauthor. “This paper represents the first step in that understanding — complexity in the organic chemistry beyond our expectations!”

The findings are significant enough to influence further exploration, Glen believes. Any spacecraft that flies towards Enceladus in the future should make a point of going through its plume to analyze these complex organic molecules with a high-resolution mass spectrometer to “help us determine how they were made.”

“We must be cautious, but it is exciting to ponder that this finding indicates that the biological synthesis of organic molecules on Enceladus is possible.”

The paper “Macromolecular organic compounds from the depths of Enceladus” has been published in the journal Nature.

NASA finds more evidence of water plumes on Europa

Astronomers working with NASA’s Hubble Telescope have confirmed what many researchers were already suspecting: water plumes are erupting from Jupiter’s moon Europa. This means that we could sample the water on the satellite without having to drill into it.

This composite image shows suspected plumes of water vapor erupting at the 7 o’clock position off the limb of Jupiter’s moon Europa. Credits: NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center

If I asked you to guess where we have the best chances of finding life outside of Earth, you’d be hard pressed to think about Europa. But Jupiter’s frozen moon is definitely a likely candidate. We’ve written extensively before about the life harboring possibilities of Europa. Beneath the frozen surface, Europa hosts a salty ocean. There are already some indications about the chemistry of that ocean and its life hosting capabilities, but acquiring valuable samples would be very difficult because we’d have to drill through a lot of ice. Thankfully, we might get a bit of help from the local geology – basically, we could just send a shuttle there and the water might come to it.

“Europa’s ocean is considered to be one of the most promising places that could potentially harbor life in the solar system,” said Geoff Yoder, acting associate administrator for NASA’s Science Mission Directorate in Washington. “These plumes, if they do indeed exist, may provide another way to sample Europa’s subsurface.”

Europa’s subsurface oceans have twice as much water than Earth’s, so there’s plenty of material to be ejected – the watery plumes are estimated to rise to about 125 miles (200 kilometers). The team, led by William Sparks of the Space Telescope Science Institute (STScI) in Baltimore observed these ejections while studying Europa’s atmosphere.

“The atmosphere of an extrasolar planet blocks some of the starlight that is behind it,” Sparks explained. “If there is a thin atmosphere around Europa, it has the potential to block some of the light of Jupiter, and we could see it as a silhouette. And so we were looking for absorption features around the limb of Europa as it transited the smooth face of Jupiter.”

[panel style=”panel-success” title=”Life on Europa” footer=””]- Jupiter’s satellite Europa has a liquid ocean beneath its frozen surface
– Europa’s ocean has similar chemical and energy characteristics to that of Earth
– This may hint at the satellite’s life-bearing possibilities, but a more robust exploration is needed.[/panel]
During observations which lasted 15 months, the team noticed plume-like features three times. This confirms a previous study conducted by Lorenz Roth of the Southwest Research Institute in San Antonio, which detected vapor erupting from the frigid south polar region of Europa. They both used the same equipment but used a different method to reach the same conclusion.

“When we calculate in a completely different way the amount of material that would be needed to create these absorption features, it’s pretty similar to what Roth and his team found,” Sparks said. “The estimates for the mass are similar, the estimates for the height of the plumes are similar. The latitude of two of the plume candidates we see corresponds to their earlier work.”

However, even if these plumes are real, there’s no evidence that they are connected to the subsurface ocean. Europa’s surface is riddled with geological features, cracks and fissures, which could host liquid pockets of water – the plumes could originate there.

Both NASA and the European Space Agency are planning missions to Europa, and many astronomers are eagerly supporting a thorough exploration of the satellite. There is already a NASA spacecraft at Jupiter called Juno, which may provide more information about these plumes, but is not designed for this purpose.

“We took great pains to make sure that that spacecraft does not get anywhere near Europa, because we want to protect Europa from contamination,” says Curt Niebur, NASA’s program scientist for outer planets missions.

The work by Sparks and his colleagues will be published in the Sept. 29 issue of the Astrophysical Journal.

Strange, Unexplainable Clouds Hover over Mars

Mysterious cloud-like formations hovering over Mars challenge our understanding of the Red Planet’s climate. Interestingly, amateur astronomers spotted the bizarre feature rising off the edge of the red planet in March and April of 2012 and since then, no satisfying answer regarding to their formation has been put forth. Now, scientists have concocted a new theory, but there’s only one problem – it poses more questions than it answers.

Dust storms on the Martian surface usually produce low-altitude plumes. Image via JPL/NASA.

A team of astronomers led by astronomer Agustín Sánchez-Lavega of the University of the Basque Country in Bilbao, Spain suggests that the plume was either a cloud of ice particles or a Martian aurora. The haze extending more than 600 miles from the surface of Mars has scientists baffled.

“This observation is a big surprise,” says Aymeric Spiga, a planetary scientist at the University of Pierre and Marie Curie in Paris, who was not involved in the work. “Another puzzle on Mars!”

The thing is that the plumes/clouds were observed at great heights, and this is really hard to explain. The simplest possibility would be that the plumes were formed by shards of frozen carbon dioxide or water vapour, but if this is the case, then the atmosphere should be much colder than currently estimated. Another possibility is that Martian dust storms kicked dust up to the high altitudes, but this has not been observed before, and it’s not clear if it can actually happen. Astronomers also suggested that it may be an aurora – an interaction between charged particles from the Sun and a planet’s magnetic field – but there’s really no evidence supporting an aurora.

A mysterious Martian plume (circled) and its changing shape (left) captured on 21 March 2012. Image credits: W. Jaeschke and D. Parker/Grupo Ciencias Planetarias/UPV/EHU/NOAA

“We know in this region on Mars, there have been auroras reported before. But the intensities we are reporting are much much higher than any auroras seen before on Mars or on Earth. It would be 1,000 times stronger than the strongest aurora, and it is difficult to come to terms that Mars has such an intense aurora.”

Indeed, according to this new research, the most likely possibility is the ice plume.

“The ice plume is a little more reasonable,” says Nicholas Heavens, a planetary astronomer at Hampton University in Virginia

But no matter which possibility turns out to be true, it will redefine our understanding of the Martian atmosphere. Munoz hopes that, inspired by his paper, other astronomers will come up with other theories or refine the already existing ones. Until then, researchers wait for the phenomenon to repeat itself, in order to gather more data.

Journal Reference: Sánchez-Lavega, A. et al. Nature http://dx.doi.org/10.1038/nature14162 (2015).

Tectonics on Enceladus

As you may or may not know, we’ve launched a new section of our website: Science Questions and Answers – a section aimed at you guys, where you can ask all questions science-related, and share your knowledge with others. We’re still in the beta version, but please, feel free to ask away – we’ll do our best to answer, answer, and vote.

So recently, somebody asked about tectonics on Enceladus. How does tectonics even work on a satellite like Enceladus? Well…

Plate tectonics

plate tectonics

Plate tectonics is a theory that emerged in the 1970s, as an attempt to describe the large-scale motions of Earth’s lithosphere. Basically, the litosphere of the Earth is composed of distinct rigid plates, comprising of continental crust or oceanic crust. These plates are in a continuous relative movement.

enceladus tectonics 1

Plate tectonics is, at its very basic level, a kinematic phenomenon. Generally, it is accepted that tectonic plates are able to move because of the relative density of oceanic lithosphere and the relative weakness of the asthenosphere, but there is still a lot of debate here. The energy is provided by dissipation of heat from the mantle through convection currents; how mantle convection relates directly and indirectly to the motion of the plates is a matter of ongoing study and discussion in geodynamics.

Enceladus tectonics

enceladus tectonics 2

Enceladus is a moon of Saturn, with a mean diameter of 505 kilometers, seven times smaller than the Earth’s Moon; it is covered in ice, but seems to have considerable amounts of water beneath its frozen surface. The surface is so cold that instead of traditional volcanoes, the surface of Enceladus is riddled with cryovolcanoes – volcanoes that erupt volatiles such as water, ammonia or methane, instead of molten rock.

Voyager 2 provided the first signs of tectonics on Enceladus; troughs, scarps, and belts of grooves and ridges were all observed. Perhaps the most shocking evidence was rifts; a rift is a linear zone where the litosphere is being bulled apart by tectonic forces. Observed canyons are up to 200 km long, 5–10 km wide, and one km deep. These features are relatively young and seem active.

Another evidence of tectonics is the grooved terrain; the surface of Enceladus is scarred with curvilinear grooves and ridges which often separate smooth areas from impact craters. Other tectonic features include numerous fractures on the surface of the moon. All in all, the geodynamic evidence is pretty convincing, but there’s even more.

enceladus stripes

Recent data from the Cassini spacecraft highlighted, aside from the prominent tectonic features, intense heat flow and geyser like plumes. Therefore, in the deeps of Enceladus, there lies a significant source of heat. Even a tiny, icy moon like Enceladus can develop complex surficial geomorphologies, high heat fluxes, and geyser-like activity, even without convection currents – which raises an interesting discussion about Earth’s tectonics, but that’s a different story.

Exobiology implications

Not entirely related to the question… but. If the satellite has a hot core and an icy surface, it’s only logical that it has a liquid water habitat inside, which is actually quite likely to host life! Researchers and exobiologists in particular are speculating a lot on this matter, and Enceladus is one of the top candidates for extraterrestrial life in our solar system.

Enceladus on Saturn's E-ring

A salty ocean under Saturn’s moon surface

Plumes springing from Enceladus' surface spray water ice out from many locations along the “tiger stripes” near the moon's south pole. (c) NASA/JPL/SSI

Plumes springing from Enceladus' surface spray water ice out from many locations along the “tiger stripes” near the moon's south pole. (c) NASA/JPL/SSI

Launched in 1997 on a mission to study Saturn and its satellites, the Casisni spacecraft reached the system in 2004. Since then it has provided numerous invaluable scientific findings regarding the second largest planet in our solar system, and other important scientific findings alike. One such finding was detailed in a recently published study, which speculate with strong backed up scientific evidence that there may actually be a subterranean liquid saltwater ocean under Saturn’s moon Enceladus.

Just one of Saturn’s 19 known moons, Enceladus has always been an impressive sight for both eyes and science. The potentially remarkable lead came after icy spray ejected from “tiger stripe” surface fractures at the moon’s south pole, were analyzed by Cassini’s  Cosmic Dust Analyser, or CDA. The device measured the composition of freshly ejected plume grains, which hit the probe at speeds of up to 11 miles per second, which lead to their vaporization. The constituents of the resulting vapor clouds were then separated and broken down by the CDA for researchers to analyze.

Enceladus on Saturn's E-ring

Enceladus on Saturn's E-ring

It is believed that the plume grains are responsible for the formation of Saturn’s E-ring, it’s outmost ring. The interesting part comes around here though; what researchers found was that ice grains found further out from Enceladus were very small and poor in ice, closely matching the composition of the E Ring. Remarkably, when going closer towards the moon, the Cassini observations indicate that relatively large, salt-rich grains dominate.

“There currently is no plausible way to produce a steady outflow of salt-rich grains from solid ice across all the tiger stripes other than the salt water under Enceladus’ icy surface,” says Frank Postberg of the University of Germany, lead author of a study published in Nature this month.

These salt-rich particles are considered to have an “ocean-like” composition that indicates most, if not all, of the expelled ice comes from the evaporation of liquid salt water rather than from the icy surface of the moon, researchers say.

“The study indicates that ‘salt-poor’ particles are being ejected from the underground ocean through cracks in the moon at a much higher speed than the larger, salt-rich particles,” says study co-author Sascha Kempf of the Laboratory for Atmospheric and Space Physics at the University of Colorado-Boulder.

You may be wondering how come this icy-salt gets blown out into space – this comes as a result of the slow freeze process of salt water. As such, the salt is spilled out, leaving pure water ice behind. Researchers argue that there could be a salty ocean under Enceladus’ surface since if the plumes would have came from up above, on the surface, the registered salt levels shouldn’t have been as high as it has been measured.

“The E Ring is made up predominately of such salt-poor grains, although we discovered that 99 percent of the mass of the particles ejected by the plumes was made up of salt-rich grains, which was an unexpected finding,” says Kempf. “Since the salt-rich particles were ejected at a lower speed than the salt-poor particles, they fell back onto the moon’s icy surface rather than making it to the E Ring.”

Based on this assumptions and subsequent computations, researchers  believe that perhaps 50 miles beneath the surface crust of Enceladus lies a thick layer of water somewhere between its rocky core and the icy mantle. The latter is is kept in a liquid state by gravitationally driven tidal forces created by Saturn and several neighboring moons, as well as by heat generated by radioactive decay.

“This study implies that nearly all of the matter in the Enceladus plumes originates from a saltwater ocean that has a very large evaporating surface,” says Kempf.

“Enceladus is a tiny, icy moon located in a region of the outer Solar System where no liquid water was expected to exist because of its large distance from the sun,” says Nicolas Altobelli, European Space Agency’s project scientist for the Cassini-Huygens mission. “This finding is therefore a crucial new piece of evidence showing that environmental conditions favorable to the emergence of life may be sustainable on icy bodies orbiting gas giant planets.”

The study comes right on the heels of another similar remarkable find which also speculated on the presence of an ocean of water on another of Saturn’s moons, this time on Titan.

source

Geophysics shows plume of Yellowstone volcano is much larger than previously believed

Yellowstone is without a doubt one of the most fascinating places on the face of the planet. But it doesn’t only attract families or people who want to relax, but it attracts scientists as well, and among them, geologists and geophysicists hold a top spot. University of Utah researchers made the first large-scale picture of the electrical conductivity of the enormous underground plume of hot and partially molten rock that feeds the Yellowstone volcano. The image suggests that it is much bigger than previously thought before, when it was also investigated with geophysical methods, but in the form of seismic waves.

“It’s like comparing ultrasound and MRI in the human body; they are different imaging technologies,” says geophysics Professor Michael Zhdanov, principal author of the new study and an expert on measuring electric and magnetic fields, with the purpose of investigating underground objectives.

In a previous 2009 study, researchers (Smith) used seismic waves from earthquakes to make an accurate image of the plume that feeds the volcano. In addition to other factors, seismic waves travel faster in cold rocks and slower in hotter rocks, so seismic velocity information can be used to make a pretty accurate 3D picture, much like X-rays are combined to make a medical CT scan.

But in this type of cases, electric measurements can be much more direct and offer much more answers, but they measure slightly different things. Seismic analysis shows which rocks are hotter and slow down waves, while electric measurements show the conductivity of the rocks, and is especially sensible to briny fluids that conduct electricity.

“It [the plume] is very conductive compared with the rock around it,” Zhdanov says. “It’s close to seawater in conductivity.”

The new study doesn’t say anything about the chances of a catastrophic eruption at Yellowstone, but it does seem to suggest than when it is going to come, it will be bigger than previously expected.