Archive for the ‘Clouds’ Category


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 Phys.org.

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?

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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.

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Venus


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 Phys.org.

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

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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?

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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.

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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 Phys.org.

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.

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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 Phys.org.

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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.

shaviv-fig4

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

Background:

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.

 

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Clouds are climate wildcards says Phys.org. 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.

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energy-budget-fixed

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.

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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.

ABSTRACT

  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.
  2. INTRODUCTION
    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.

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Is this how it works? [image credit: politics.ie]


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
H/T The GWPF

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.

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Uranus [image credit: NASA]


One of the two processes involved is “due to high-speed particles from outside the solar system, known as galactic cosmic rays, bombarding the atmosphere and influencing the formation of clouds”, reports Phys.org. If so, it looks like further evidence for the Svensmark hypothesis.

Changes in solar activity influence the colour and formation of clouds around the planet, researchers at Oxford and Reading universities found.

The icy planet is second furthest from the sun in the solar system and takes 84 Earth years to complete a full orbit – one Uranian year.

The researchers found that, once the planet’s long and strange seasons are taken into account, it appears brighter and dimmer over a cycle of 11 years. This is the regular cycle of solar activity which also affects sun spots.

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cr-atmos

Illustration of cosmic rays interacting with the atmosphere. A proton with energy of 100 GeV interact at the top of the atmosphere and produces a cascade of secondary particles who ionize molecules when traveling through the air. One 100 GeV proton hits every m2 at the top of the atmosphere every second.

H/T GWPF: Researchers have claimed a breakthrough in understanding how cosmic rays from supernovas react with the sun to form clouds, which impact the climate on Earth.

The findings have been described as the “missing link” to help resolve a decades long controversy that has big implications for climate science.

Lead author, Henrik Svensmark, from The Technical University of Denmark has long held that climate models had greatly underestimated the impact of solar activity.

He says the new research identified the feedback mechanism through which the sun’s impact on climate was varied.

Professor Svensmark’s theories on solar impact have caused a great deal of controversy within the climate science community and the latest findings are sure to provoke new outrage.

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Credit: Environment Canada


Whether this tells us anything about long-term climate trends is not clear, but worth a mention anyway. The report from Phys.org states: ‘Scientists said the smaller ozone hole extent in 2016 and 2017 is due to natural variability and not a signal of rapid healing’.

Measurements from satellites this year showed the hole in Earth’s ozone layer that forms over Antarctica each September was the smallest observed since 1988, scientists from NASA and NOAA announced today.

According to NASA, the ozone hole reached its peak extent on Sept. 11, covering an area about two and a half times the size of the United States – 7.6 million square miles in extent – and then declined through the remainder of September and into October.

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Credit: NASA

The report at Phys.org explains that “Even though the moon blocking the sun during a solar eclipse and clouds blocking sunlight to Earth’s surface are two different phenomena, both require similar mathematical calculations to accurately understand their effects.”

It was mid-afternoon, but it was dark in an area in Boulder, Colorado on Aug. 3, 1998. A thick cloud appeared overhead and dimmed the land below for more than 30 minutes. Well-calibrated radiometers showed that there were very low levels of light reaching the ground, sufficiently low that researchers decided to simulate this interesting event with computer models.

Now in 2017, inspired by the event in Boulder, NASA scientists will explore the moon’s eclipse of the sun to learn more about Earth’s energy system. On Aug. 21, 2017, scientists are looking to this year’s total solar eclipse passing across America to improve our modelling capabilities of Earth’s energy.

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Despite confessing to being ‘baffled by clouds’, climate science and its media followers are still prone to assertions like ‘as the world warms’ – as though it’s bound to do so indefinitely.

Though we see them every day, clouds remain such a mystery to scientists that they are inhibiting climate change predictions. But a new atlas could be a game changer, thinks DW.COM.

Nothing beats a lazy afternoon sitting on the grass and watching the clouds roll by. These white fluffy friends can feel like a constant and comforting presence in life. And since the dawn of air travel, as folk singer Joni Mitchell once sang, we’ve looked at clouds from both sides now.

But as Mitchell cautioned, somewhow we still don’t know clouds at all. Her words were true in 1969, and they are still true today.
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Credit: airbus.com

Credit: airbus.com


The observed radiation surges seem to occur ‘at relatively high latitudes, well above 50 degrees in both hemispheres’. They suspect certain magnetic phenomena could be at work. Korean researchers may have found something similar occurring at middle latitudes.

A new study published in the peer-reviewed journal Space Weather reports the discovery of radiation “clouds” at aviation altitudes. When airplanes fly through these clouds, dose rates of cosmic radiation normally absorbed by air travelers can double or more, reports Spaceweather.com.

“We have flown radiation sensors onboard 264 research flights at altitudes as high as 17.3 km (56,700 ft) from 2013 to 2017,” says Kent Tobiska, lead author of the paper and PI of the NASA-supported program Automated Radiation Measurements for Aerospace Safety (ARMAS). “On at least six occasions, our sensors have recorded surges in ionizing radiation that we interpret as analogous to localized clouds.”
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Venus_atm
Sci News reports scientific findings that ‘winds, the water content, and the cloud composition – are somehow connected to the properties of Venus’ surface itself’.

Using data from ESA’s Venus Express spacecraft, European planetary researchers have shown how weather patterns seen in Venus’ cloud layers are directly linked to the topography of the surface below.

Venus is famously hot. The average temperature on the Venusian surface is 864 degrees Fahrenheit (462 degrees Celsius).

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