ESA Satellites showing clouds of sulphur dioxide from Bardarbunga volcano

A plume of sulphur dioxide was detected drifting towards Europe from Iceland’s Bardarbunga volcano late on 4 September 2014. 

These images are based on data from the Spinning Enhanced Visible & InfraRed Imager (SEVIRI) on the Meteosat Second Generation (MSG) mission. 

Credit: NILU

Satellites are showing clouds of sulphur dioxide from Iceland's restive Bardarbunga volcano.

ESA's Volcanic Ash Strategic Initiative Team (VAST) and Support to Aviation Control Service (SACS) are monitoring the situation closely, and have detected sulphur dioxide emissions since early September.

A small cloud of sulphur dioxide has been drifting toward Europe since late last night.

The Bardarbunga volcano has shown heightening activity since mid-August, causing thousands of local earthquakes, spewing lava and threatening air travel.

The aviation alert level is high, fluctuating between orange and red as the potential of eruption is increased.

"The current volcanic activity is typically effusive and no ash has been detected so far with satellite measurements," said Nicolas Theys from the Belgian Institute for Space Aeronomy.

"SACS, VAST and ESA partners will continue monitoring volcanic emissions over Bardarbunga and provide added-value services, in case the eruption becomes explosive, causing ash-producing activity with possible consequences for European air space."

The presence of ash in the atmosphere can endanger jet engines, so timely information about ash, sulphur dioxide clouds and their dispersion are crucial to alert civil aviation authorities.

Earth-observing satellites can provide this information, especially for toxic gases like sulphur dioxide, which cannot be seen with the naked eye.

With frequent and worldwide measurements of ash plumes and sulphur dioxide emissions, satellites help to improve aviation safety.

This animation shows the spread of sulphur dioxide from Iceland’s Bardarbunga volcano from 31 August to 4 September 2014, as detected by the GOME-2 instrument on the MetOp-A and -B satellites. 

Credit: BIRA/IASB

SACS and VAST uses multiple satellites, including Europe's MetOp and Meteosat missions, to provide early warning information about volcanic eruptions.

When an eruption occurs, an alert is sent to interested users, most notably to Volcanic Ash Advisory Centres and airlines, and public maps are generated showing the extent and intensity of the volcanic plumes.

NASA Cassini Tracks Clouds Developing Over a Titan Sea

This animated sequence of Cassini images shows methane clouds moving above the large methane sea on Saturn's moon Titan known as Ligeia Mare.

Image Credit: NASA /JPL-Caltech /Space Science Institute

As NASA's Cassini spacecraft sped away from Titan following a relatively close flyby, its cameras monitored the moon's northern polar region, capturing signs of renewed cloud activity.

Image Credit: NASA /JPL-Caltech /Space Science Institute

NASA's Cassini spacecraft recently captured images of clouds moving across the northern hydrocarbon seas of Saturn's moon Titan.

This renewed weather activity, considered overdue by researchers, could finally signal the onset of summer storms that atmospheric models have long predicted.

The Cassini spacecraft obtained the new views in late July, as it receded from Titan after a close flyby. Cassini tracked the system of clouds developing and dissipating over the large methane sea known as Ligeia Mare for more than two days.

Measurements of cloud motions indicate wind speeds of around 7 to 10 mph (3 to 4.5 meters per second).

For several years after Cassini's 2004 arrival in the Saturn system, scientists frequently observed cloud activity near Titan's south pole, which was experiencing late summer at the time.

Clouds continued to be observed as spring came to Titan's northern hemisphere. But since a huge storm swept across the icy moon's low latitudes in late 2010, only a few small clouds have been observed anywhere on the icy moon.

The lack of cloud activity has surprised researchers, as computer simulations of Titan's atmospheric circulation predicted that clouds would increase in the north as summer approached, bringing increasingly warm temperatures to the atmosphere there.

"We're eager to find out if the clouds' appearance signals the beginning of summer weather patterns, or if it is an isolated occurrence," said Elizabeth Turtle, a Cassini imaging team associate at the Johns Hopkins University Applied Physics Lab in Laurel, Maryland.

"Also, how are the clouds related to the seas? Did Cassini just happen catch them over the seas, or do they form there preferentially?"

A year on Titan lasts about 30 Earth years, with each season lasting about seven years. Observing seasonal changes on Titan will continue to be a major goal for the Cassini mission as summer comes to Titan's north and the southern latitudes fall into winter darkness.

NASA RXTE: Clouds seen circling supermassive black holes - video

Credit: NASA

Astronomers see huge clouds of gas orbiting supermassive black holes at the centers of galaxies using NASA's Rossi X-Ray Timing Explorer satellite (RXTE).

Once thought to be a relatively uniform, fog-like ring, the accreting matter instead forms clumps dense enough to intermittently dim the intense radiation blazing forth as these enormous objects condense and consume matter, they report in a paper to be published in the Monthly Notices of the Royal Astronomical Society, available online now.

Evidence for the clouds comes from records collected over 16 years by NASA's Rossi X-Ray Timing Explorer satellite (RXTE), a satellite in low-earth orbit equipped with instruments that measured variations in X-ray sources.

Those sources include active galactic nuclei, brilliantly luminous objects powered by supermassive black holes as they gather and condense huge quantities of dust and gas.

By sifting through records for 55 active galactic nuclei Alex Markowitz, an astrophysicist at the University of California, San Diego and the Karl Remeis Observatory in Bamberg, Germany and colleagues found a dozen instances when the X-ray signal dimmed for periods of time ranging from hours to years, presumably when a cloud of dense gas passed between the source and satellite.

Mirko Krumpe

Mirko Krumpe of the European Southern Observatory in Garching, Germany and Robert Nikutta, of Andrés Bello University in Santiago, Chile co-authored the report, which confirms what recent models of these systems have predicted.


This animation shows an artist's rendition of the cloudy structure revealed by a study of data from NASA's Rossi X-Ray Timing Explorer satellite (RXTE). Credit: NASA

The clouds they observed orbit a few light-weeks to a few light-years from the center of the active galactic nuclei.

One, in a spiral galaxy in the direction of the constellation Centaurus designated NGC 3783, appeared to be in the midst of being torn apart by tidal forces.

More Information: 'First X-ray-Based Statistical Tests for Clumpy-Torus Models: Eclipse Events from 230 Years of Monitoring of Seyfert AGN': Alex Markowitz (Univ. Calif., San Diego and Karl Remeis Sternwarte/ECAP), Mirko Krumpe (European Southern Observatory and Univ. Calif., San Diego), Robert Nikutta (Univ. Andrés Bello): arXiv:1402.2779 [astro-ph.GA]

ESA Venus Express Image: Chasing clouds

Clouds regularly punctuate Earth's blue sky, but on Venus the clouds never part, for the planet is wrapped entirely in a 20 km-thick veil of carbon dioxide and sulphuric dioxide haze. 

This view shows the cloud tops of Venus as seen in ultraviolet light by ESA Venus Express spacecraft from a distance of about 30 000 km. 

Much of the image is occupied by the planet's southern hemisphere, with the south pole at the bottom of the frame and the equator close to the top.

The visible top cloud layer seen in the image is about 70 km above the planet's surface.

The observed pattern of bright and dark markings is caused by variations in an unknown absorbing chemical at the Venus cloud tops.

It is abundant in the low latitudes (upper part of the image) that make this region look dark in UV.

In the brighter high latitudes (lower part of the image), the UV absorber is either in deficit or masked by a thick haze of a reflecting aerosol.

The shapes of the cloud top features show evidence of vigorous circulation and dynamics in the planet's atmosphere.

At low latitudes, mottled cloud formations associated with turbulent activities are seen, while smooth, laminar flows are visible in middle to high latitudes.

The wind speed is derived from tracking cloud features as they whip around the planet faster than 100 metres per second.

This 'super-rotating' atmosphere completes one circuit every four Earth days, in comparison to the planet's surface, which takes 224 days to complete one revolution about its axis.

Mammatus clouds are very rare and form after thunderstorms.

Mammatus clouds are very rare and normally form after thunderstorms.

Scientists use A-Train satellites to measure how pollution particles affect clouds

Described as a satellite constellation, the 'A-Train' is shown in this artist's conception. 

The close timing and engineering of these satellites along a track means that they function as if they were all on the same platform. 

Data collected by the A-Train gave scientists in this CloudSat study more complete information on atmospheric particles around the globe. Photo: NASA.

Grabbing a virtual tiger by the tail, scientists led by researchers at Pacific Northwest National Laboratory directly linked a cloud's inclination to rain to its effects on the climate.

Using global satellite data and complex calculations, they were able—for the first time—to develop a proxy measurement for one of the most vexing questions in atmospheric science: how tiny particles in the atmosphere affect the amount of cloud.

Using this new metric, they showed that aerosols' effects on clouds are overestimated by as much as 30 percent in a global climate model. The results were published in the journal Geophysical Research Letters.

"Our study helps narrow the large aerosol-cloud interaction uncertainties in projections of future global warming," said Dr. Minghuai Wang, atmospheric scientist at PNNL and lead author of the study.

"Wide ranges of estimates in aerosol effects on clouds have made it challenging to understand how clouds really affect the climate." Understanding clouds and their effects on climate is a formidable challenge in trying to predict how the climate will change by the end of the century.

On the line are questions of future melting of the polar ice, drought and water shortages, and increases in extreme weather events. One particularly tough question is how tiny pollution-caused particles in the atmosphere will affect clouds.

This study shows how satellite observations can be used to hone in on aerosol effects on clouds and make it possible to better understand how clouds will affect climate.

"The use of satellite observations in studying climate processes like these is absolutely critical because it is the only way to obtain cloud and aerosol measurements over the whole globe," said Dr. Mikhail Ovchinnikov, PNNL atmospheric scientist and co-author of the study.

The study, led by PNNL scientists, constructed a new metric for rain frequency susceptibility, then closely correlated that metric to the aerosol effect on cloud amount, which is the total amount of water in the cloud and the cloud's size.

This metric, along with satellite measurements, was then used in three global climate models to find new ranges of cloud amount change due to pollution-caused aerosol particles, compared to current estimates.

The team, for the first time, used "A-Train" satellite observations which collect coincident global measurements of aerosols, clouds, and precipitation to develop a new metric, termed rain frequency susceptibility or "S-POP."

This metric provides a quantitative measure of the sensitivity of rain frequency to the amount of aerosols in clouds.

They showed how S-POP is closely correlated to aerosols' effects on cloud amount, using three global climate models, including a multi-scale aerosol climate model developed at PNNL (PNNL-MMF) that embeds a cloud-resolving model at each grid column of a host global climate model.

Finally, the relationship between S-POP and the aerosol effects on cloud amount from the global climate models together with the observed rain frequency susceptibility from A-Train observations were used to estimate aerosol effects on cloud amount in global climate models.

They showed that in one global model, the National Center for Atmospheric Research's Community Atmosphere Model version 5 (CAM5), aerosol effects on clouds were overestimated by 30 percent.

This research also provides a guide for the development and evaluation of new parameterizations, techniques to computationally represent complex small-scale systems, of aerosol effects on clouds in global climate models.

The researchers plan to apply S-POP to evaluate cloud amount based on rain frequency susceptibility in other global climate models, and guide further improvement of the aerosol indirect effects estimations in CAM5 and the PNNL-MMF multi-scale aerosol-climate model.

Read the paper: "Constraining Cloud Lifetime Effects of Aerosols Using A-Train Satellite Observations," Geophysical Research Letters 39:L15709. DOI:10.1029/2012GL052204

NASA Sound Rockets leave Tracer Clouds

This photo provided by NASA shows chemical tracers that were released from five rockets launched from NASA's Wallops Island test flight facility in Atlantic, Virginia, US.

The tracers form white clouds that allow scientists and the public to visualise upper level jet stream winds.

Picture: NASA/AP

Clouds and Stars over Cotopaxi Volcano in Ecuador

Explanation: What's happening above the Cotopaxi volcano in Ecuador? Quite a bit, from the looks of the above one-night, time-lapse movie, taken earlier this month. The majestic volcano is first seen through breaks in fast moving clouds as the movie begins.

Soon the clouds have dissipated and a sky filled with stars seems to rotate about the snow-peaked volcano's peak. The band of our Milky Way Galaxy, the dark Coal Sack nebula, and the Southern Cross can all be seen overhead.

Satellites steak by from several directions. Soon thin clouds roll by and seem to make the brightest stars sparkle. On the volcano (starting at about 1:13 of the movie), the lights of climbers flash.

Near the end of the movie, a bright airplane passes over the peak with a residual trail seen drifting away.

European Fighter plane - Typhoon

Climate Change - Geoengineering