Archive for the ‘Clouds’ Category

More on the mysteries behind noctilucent clouds. Lots of extra water vapour has turned up this season that can’t easily be explained.

June 19, 2019: The 2019 season for noctilucent clouds (NLCs) has been remarkable, maybe the best ever, with NLCs appearing as far south as Los Angeles CA and Albuquerque NM. What’s going on? Researchers aren’t sure, but Lynn Harvey of the University of Colorado’s Laboratory for Atmospheric and Space Physics has just found an important clue.

“The mesosphere is quite wet,” she says. “Water vapor concentrations are at their highest levels for the past 12 years.”

electricblueNoctilucent clouds over Piwnice, Poland, on June 18th. Credit: Piotr Majewski

Noctilucent clouds form when summertime wisps of water vapor rise to the top of the atmosphere. Water molecules stick to specks of meteor smoke, gathering into icy clouds that glow electric blue when they are hit by high altitude sunlight.

When noctilucent clouds began appearing at unusually low latitudes in early June, Harvey took a look at data from NASA’s Microwave…

View original post 285 more words

Something of a mystery developing here. Open season for theories.

June 11, 2019: On June 8th and 9th, many people who have never previously heard of “noctilucent clouds” (NLCs) found themselves eagerly taking pictures of them–from moving cars, through city lights, using cell phones and iPads. “I have never seen clouds like this before!” says Tucker Shannon, who took this picture from Corvallis, Oregon:

“I heard that they may have been seeded by meteoroids,” says Shannon.

That’s correct. NLCs are Earth’s highest clouds. Seeded by meteoroids, they float at the edge of space more than 80 km above the planet’s surface. The clouds are very cold and filled with tiny ice crystals. When sunbeams hit those crystals, they glow electric-blue.

Noctilucent clouds used to be a polar phenomenon. In recent years, however, researchers have noticed their electric-blue forms creeping south. Is it climate change? Or the solar cycle? No one knows for sure.

This past weekend…

View original post 172 more words

From the ‘observing tips’: ‘Look west 30 to 60 minutes after sunset when the sun has dipped below the horizon. If you see luminous blue-white tendrils spreading across the sky, you may have spotted a noctilucent cloud.’

May 31, 2019: A huge blue cloud of frosted meteor smoke is pinwheeling around the Arctic Circle. NASA’s AIM spacecraft spotted its formation on May 20th, and it has since circled the North Pole one and a half times, expanding in size more than 200-fold.

“These are noctilucent clouds,” says Cora Randall of the AIM science team at the University of Colorado. “And they are going strong.”


Noctilucent clouds (NLCs) in May are nothing unusual. They form every year around this time when the first wisps of summertime water vapor rise to the top of Earth’s atmosphere. Molecules of H2O adhere to specks of meteor smoke, forming ice crystals 80 km above Earth’s surface. When sunbeams hit those crystals, they glow electric-blue.

But these NLCs are different. They’re unusually strong and congregated in a coherent spinning mass, instead of spreading as usual all across the polar cap.


View original post 302 more words

Polar Mesospheric Summer Echoes

Posted: May 22, 2019 by oldbrew in atmosphere, Clouds, physics

Noctilucent clouds form when molecules from summertime water vapour stick to the microscopic debris of disintegrated meteoroids.

May 21, 2019: Every summer since the late 1970s, radars probing Earth’s upper atmosphere have detected strong echoes from altitudes between 80 km and 90 km. The signals come from noctilucent clouds (NLCs).  NASA’s AIM spacecraft is still waiting to spot the first NLCS of the 2019 season, but the echoes have already begun. Rob Stammes of the Polarlightcenter in Lofoten, Norway, detected them on May 19th and 20th:


“I detected these VHF signals from Eastern Europe,” he explains. “They reflected from the mesosphere back down to my receiver in Norway. The wave patterns were recognizable and very strong.”

Researchers call them “Polar Mesospheric Summer Echoes” or “PMSEs.” They occur over the Arctic during the months of May through August, and over the Antarctic during the months of November through February. These are the same months that NLCs appear.

The underlying physics of these echoes is still uncertain.

View original post 199 more words


Growth of polar sea ice is of course mainly a winter phenomenon, each polar region being continuously dark for several months during that period. The researchers here looked at the role of clouds during the dark Antarctic winter and as one said, “Fewer clouds mean more heat is lost from the ocean.” This then led to higher summer sea ice in some areas.
Which begs the question: why were there fewer winter clouds?

– – –
H/T The Global Warming Policy Forum (GWPF)

BEIJING, April 26 (Xinhua) — Researchers have discovered that lower cloud coverage in the Antarctic can promote sea ice growth.

Unlike the rapid decline of Arctic sea ice in the warming climate, Antarctic sea ice witnessed a modest extension over the past four decades, according to the paper published in the Journal of Geophysical Research-Atmospheres. […]


As the professor quoted below says: “Despite over 250 years of research, how lightning begins is still a mystery.” Tesla had a few ideas though (video).

In a first-of-its-kind observation, researchers from the University of New Hampshire Space Science Center have documented a unique event that occurs in clouds before a lightning flash happens, says

Their observation, called “fast negative breakdown,” documents a new possible way for lightning to form and is the opposite of the current scientific view of how air carries electricity in thunderstorms.


As the ‘official’ (IPCC, Met Office etc.) view insists that more warming lies ahead, other analysts foresee significant cooling. Clearly, somebody has to be wrong.

The Next Grand Minimum

Definition — cusp: a point of transition between two different states

The transition from the Medieval Warm Period and the Little Ice Age was punctuated by extreme climate events, intense storms, floods, and droughts according to Lynn Ingram and Francis Malamud-Roam writing in The West Without Water. According to the authors, the transition from the Little Ice Age to the Modern Warm Period also experienced erratic weather extremes. Wolfgang Behringer, writing in the Cultural History of Climate, found similar transitions to more extreme weather. These extreme record-setting events are a signal that the overall climate is moving to a different state, in other words on the cusp of climate change.

Some recent record events:

Japan’s northern island of Hokkaido: Record cold temperatures, minus 24.4 C, the lowest seen since it began compiling such data in 1957.

Seattle: Coldest February in 30 years, the 4th coldest in 75 years, the…

View original post 201 more words

Another possible factor to consider in the climate cause and effect puzzle.

An international team of researchers has found evidence that suggests the cooling effect of aerosols in cumulus and MSC clouds is twice as high as thought, reports

In their paper published in the journal Science, the group describes their analyses of data from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) database and what they found.

Global warming is very much in the news of late, as the planet continues to heat up. But one of the factors at play is very seldom mentioned—the role of clouds in cooling the planet.

They do so by reflecting heat from the sun back into space. But how much of the reflecting occurs due to water in the clouds and how much is due to aerosols?


An artist’s image of a hot-Jupiter exoplanet [credit: NASA]

But they seem to have something in common that scientists were not expecting: their nightside temperature.

New research shows how the nightside of all hot Jupiters is covered in clouds, reports Discover Magazine.

Cloudy Hot Jupiters

“Hot Jupiters” exoplanets that resemble our own Jupiter, except for being, well, hot, have another side to them.

We mean this literally: The planets usually don’t rotate [see Tidal Locking note below], so one side is always facing their star, and the other remains in permanent night.

A new study is suggesting that these night sides probably all look the same, no matter where you go in the universe.



The researchers say the key to this is a phenomenon closely connected to Earth’s polar jet streams.

A Japanese research group has identified a giant streak structure among the clouds covering planet Venus based on observation from the spacecraft Akatsuki, reports

The team also revealed the origins of this structure using large-scale climate simulations.


Does it snow on Mars?

Posted: December 30, 2018 by oldbrew in atmosphere, Clouds, solar system dynamics
Tags: ,

Clouds on Mars [image credit: NASA]

H/T Discover Magazine

This wasn’t the first question that came to mind when I photographed these clouds, says Tom Yulsman @ ImaGeo.

But the beautiful phenomenon I witnessed eventually led me to it.
– – –
Mars is certainly cold. With temperatures that can plunge to more than negative 100 degrees Celsius, it’s bloody frigid!

But as cold as it might get, does it snow on Mars?


Jupiter dominates the solar system

Scientists predict the next parting of Jupiter’s veil of clouds for 2019. We like ‘regular pattern’ planetary mysteries.

New research finds a pattern of unique events at Jupiter’s equator, reports ScienceDaily.

A regular pattern of unusual meteorological events at Jupiter’s equator has been identified by planetary scientists at the University of Leicester.

Jupiter’s striped appearance of light zones and dark brown belts provides breathtaking views through amateur and professional telescopes alike. But Jupiter’s stripes can change and shift over poorly-understood timescales, sometimes expanding and contracting, sometimes fading away entirely.


They say “By shading and cooling the Earth’s surface, cloud cover plays a direct role in rates of global climate change”, but that’s only half the story. Cloud cover at night, i.e. the other 50% of the year, has the opposite effect and slows the rate of heat loss.

Everyday our atmosphere has to find a way to clean itself of the air, sea and soil pollution we throw at it, says

So, in order to study how this cleaning process works, the University of Melbourne’s Dr. Robyn Schofield is sailing through the pristine environment of the Southern Ocean to our most untouched continent, Antarctica—an environment with the least amount of pollution on the planet.


Saturn’s north polar vortex and hexagon along with its expansive rings. The hexagon is wider than two Earths [image credit: NASA]

Another case of observing something that wasn’t thought possible. As the report notes: ‘The presence of a hexagon way up in Saturn’s northern stratosphere, hundreds of kilometres above the clouds, suggests that there is much more to learn about the dynamics at play in the gas giant’s atmosphere.’

The long-lived international Cassini mission has revealed a surprising feature emerging at Saturn’s northern pole as it nears summertime: a warming, high-altitude vortex with a hexagonal shape, akin to the famous hexagon seen deeper down in Saturn’s clouds.

This suggests that the lower-altitude hexagon may influence what happens up above, and that it could be a towering structure spanning hundreds of kilometres in height, reports


Nir Shaviv is co-author along with Henrik Svensmark and others of a major new paper in Nature Communications titled Increased ionization supports growth of aerosols into cloud condensation nuclei. He has a write up at his Sciencebits blog. Here’s the introduction:

Our new results published today in nature communications provide the last piece of a long studied puzzle. We finally found the actual physical mechanism linking between atmospheric ionization and the formation of cloud condensation nuclei. Thus, we now understand the complete physical picture linking solar activity and our galactic environment (which govern the flux of cosmic rays ionizing the atmosphere) to climate here on Earth though changes in the cloud characteristics. In short, as small aerosols grow to become cloud condensation nuclei, they grow faster under higher background ionization rates. Consequently, they have a higher chance of surviving the growth without being eaten by larger aerosols. This effect was calculated theoretically and measured in a specially designed experiment conducted at the Danish Space Research Institute at the Danish Technical University, together with our colleagues Martin Andreas Bødker Enghoff and Jacob Svensmark.


Figure 4: The correlation between the linearly detrended sea level measured using satellite altimetry (blue dots) and a model fit which includes just two components: The sun and el Niño southern oscillation. The excellent fit implies that the two components are by far the dominant source of sea level change on short time scales


It has long been known that solar variations appear to have a large effect on climate. This was already suggested by William Herschel over 200 years ago. Over the past several decades, more empirical evidence have unequivocally demonstrated the existence of such a link, as exemplified in the examples in the box below.



Clouds are climate wildcards says This study focuses on tropical convective clouds. It seems that ‘the product of the number of clouds and their perimeter remains constant, a mathematical law known as scale invariance.’

Quoting from the ‘plain language summary’ of the study:
‘Narrowing uncertainty in forecasts of climate change has been hindered by the difficulty of representing the extraordinary complexity of clouds. Here, we show how the numbers and sizes of clouds, and their total amount, can be derived thermodynamically knowing just the atmospheric temperature and humidity profile.’

As usual an assumption of future warming is built-in, but we have to live with that approach even if we question it.

Take a look at the clouds, if there are any in your sky right now. Watch the billows, the white lofty tufts set against the blue sky. Or, depending on your weather, watch the soft grey edges smear together into blended tones that drag down through the air to the ground.

They’re an inspiration to most of us, but a nightmare for climate scientists. Clouds are exceptionally complex creatures, and that complexity makes it difficult to predict how and where they’ll form—which is unfortunate, since those predictions are essential to understanding precipitation patterns and how our climate will change in the future.



Question: If I had a container, full with air, and I suddenly decreased the volume of the container, forcing the air into a smaller volume, will it be considered as compression, will it result in an increase in temperature, and why?

Answer on Stack Exchange by Luboš Motl: Yes, it is compression and yes, it will heat up the gas.

If there’s no heat exchange between the gas and the container (or the environment), we call it an adiabatic process. For an adiabatic process involving an ideal gas (which is a very good approximation for most common gases), pVγ is constant where γ is an exponent such as 5/3. Because the temperature is equal to T=pV/nR and pV/pVγ=V1−γ is a decreasing function of V, the temperature will increase when the volume decreases.

Macroscopically, the heating is inevitable because one needs to perform work p|dV| to do the compression, the energy has to be preserved, and the only place where it can go is the interior of the gas given by a formula similar to (3/2)nRT.


An interesting contribution to the ice age debate here. Problems with Milankovitch and CO2-related theories are discussed.

Thongchai Thailand

Gerald Marsh, retired Argonne National Laboratories Physicist, challenges the usual assumption that ice age cycles are initiated by Milankovich Cycles and driven by the Arrhenius effect of carbon dioxide. He says that the key variable here is “low altitude cloud cover” driven by cosmic rays. A paper worth reading.


  1. The existing understanding of interglacial periods is that they
    are initiated by Milankovitch cycles enhanced by rising atmospheric
    carbon dioxide concentrations. During interglacials, global temperature is
    also believed to be primarily controlled by carbon dioxide concentrations,
    modulated by internal processes such as the Pacific Decadal Oscillation
    and the North Atlantic Oscillation. Recent work challenges the
    fundamental basis of these conceptions.
    The history of the role of carbon dioxide in climate begins with the work of Tyndall 1861 and later in 1896 by Arrhenius. The concept that carbon dioxide controlled climate fell into disfavor for a variety of reasons until…

View original post 1,929 more words

leak.smlThe hole in the ozone layer is now steadily closing, but its repair could actually increase warming in the southern hemisphere, according to scientists at the University of Leeds.

The Antarctic ozone hole was once regarded as one of the biggest environmental threats, but the discovery of a previously undiscovered feedback shows that it has instead helped to shield this region from carbon-induced warming over the past two decades.

High-speed winds in the area beneath the hole have led to the formation of brighter summertime clouds, which reflect more of the sun’s powerful rays.


Is this how it works? [image credit:]

An obvious problem with studies like this is that as soon as natural climate variation is invoked – to explain the lack of expected warming from so-called greenhouse gases – the argument that such gases could be a dominant factor in climate processes is then severely weakened to say the least. It is in effect an admission that such variations could cause warming as well as cooling. How long can a ‘hiatus’ last before it becomes the status quo?

Reinforcement of Climate Hiatus by Decadal Modulation of Daily Cloud Cycle
– By Jun Yin and Amilcare Porporato, Princeton University

Based on observations and climate model results, it has been suggested that the recent slowdown of global warming trends (climate hiatus), which took place in the early 2000s, might be due to enhanced ocean heat uptake.

Here we suggest an alternative hypothesis which, at least in part, would relate such slowdown to unaccounted energy reflected or re-emitted by clouds.