We really don′t know clouds at all 

Posted: March 25, 2017 by oldbrew in atmosphere, Clouds, data, Forecasting, modelling

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.

Clouds might seem a familiar part of our lives. In fact, they are one of the least-understood aspects of our environment. And that’s causing a huge headache for researchers trying to predict how the world will be affected by climate change.

Despite the critical role they play in the planet’s water cycle and heating patterns, scientists are often still baffled by how and why clouds behave the way they do. This uncertainty is the main reason climate research remains an imperfect science. Researchers just can’t say for sure how clouds are going to react to a warming environment, and that means they can’t make exact predictions about how the world will be affected by climate change.

A cloudy day
But scientists now have a new tool to unravel these mysteries. Tomorrow (23 March), the World Meteorological Organization will unveil a new, long-awaited digitized International Cloud Atlas – a modern update to an atlas started nearly 150 years ago.

“The last update was roughly 40 years ago,” WMO scientific officer Isabelle Ruedi told DW. “At that time there was no internet, no digital cameras, nothing like that. It means that nowadays the old atlas is not so accessible to people. We decided to update it to take into account the best knowledge we have of clouds.”

The new atlas is being unveiled on World Meteorological Day, which this year is being dedicated to the theme of clouds. WMO secretary-general Petteri Taalas says it offers a new chance for meteorologists and scientists to get to grips with these mysterious celestial beings – which remain both known and unknown at the same time.

“Throughout the centuries, few natural phenomena have inspired as much scientific thought and artistic reflection as clouds,” he says. “If we want to forecast weather we have to understand clouds. If we want to model the climate system we have to understand clouds. And if we want to predict the availability of water resources, we have to understand clouds.”

This new version of the atlas brings together for the first time a wealth of data, including high-tech, surface-based, space observations and remote sensing. It follows a consultation period in which photographs and other forms of evidence were gathered from all across the world.

Central to climate
So why are clouds so important to our weather patterns? Most importantly, they move water from one place to another. Clouds soak up water from lakes and dump it on dry land. When their patterns go awry, it results in droughts and floods.

Clouds also modulate heat in the atmosphere, cooling the earth by shielding it from the sun. So we know clouds are important to the weather we experience. What we don’t know is how their behavior will change as the Earth’s atmosphere gets warmer.

Sandrine Bony, author of a 2012 white paper on climate science by the World Climate Research Program, notes that the mysteries of clouds have remained frustratingly difficult to solve. “Uncertainty in estimates of the magnitude of the climate sensitivity has hardly changed in 30 years,” she explains. “Although models are getting better, some biases in modelled large-scale circulations have persisted across many cycles of model development.”

Researchers hope to use the new data contained in the atlas to focus on four initiatives aimed at doubling the knowledge of how clouds behave within the next five to 10 years.

First, they will design new tests to measure why there have been so many differences between prediction models for cloud behavior so far. They will then use this research to reduce model errors and make more reliable projections. Thirdly, they will work to better understand the connection between clouds and the convective processes that cause water to evaporate.

Work will also focus on the changing patterns of clouds already taking place due to a warming environment.

Continued here.

  1. suricat says:

    I don’t see any ‘link’ from “DW.COM” that can improve our knowledge oldbew, as this ‘cloud identification’ unifying chart is all I discovered there;


    but there’s much more to it than this, surely? What of ‘CCN’ (Cloud Condensation Nuclei)? The solid particles that enable ‘WV’ (Water Vapour) to ‘condense’ to liquid from a vapour state? Without these WV ‘supersaturates’ the atmosphere. What are the CCN differences between airborne ‘black carbon’ and ‘dust’? How does ‘RH’ (Relative Humidity) alter where ‘black carbon’ or ‘dust’ is evident? There are soooo many questions to answer more and above the ‘Cloud Recognition’ page that your ‘subject’ “DW.COM” links to.

    This is ‘boring’ oldbrew, but because its the ‘WMO'(World Meteorological Organisation), I’m not surprised. The WMO is an ‘arm’ of the ‘UN’ (United Nations) organisation, which receives its directive from the UN. The UN also has an ‘arm’ that’s responsible for reporting any changes to our climate, and in particular, ‘human caused’. Yes, this is the ‘IPCC’ (International Panel for Climate Change)!

    I’m not suggesting that there is a ‘conflict of interest’ here, just a lapse in scientific practise.

    You’ve linked to a crap site ‘ob’. Even ‘Ole Humlum’s’ site is better than this;


    and here’s his better understood mark to English viewers at ‘climate for you’;


    Where you can peruse the links to ‘clouds’.

    I don’t see what this/your post adds to the ‘collective discussion’.

    Please advise.

    Best regards, Ray.

  2. Richard111 says:

    Here is an example of cloud effects anyone can record. On a warm sunny day with clear skies and minimal wind note the mid afternoon temperature. As the sun sets and the temperature starts dropping keep an eye on the temperature.

    What is need now is a layer of cloud arriving overhead, best after midnight. This ‘cloud effect is quite common here in South West Wales.

    Now notice the temperature is rising! I’ve recorded 5 or 6 degrees rise. At night! Remember there is no wind. So how come the temperature rises at night? Back radiation.

  3. oldbrew says:

    Ray – DW.com is a news site not a technical science site so you can only expect generalities. They’re reporting the new cloud atlas.

    Richard – in your scenario which rises first, temperature or pressure, or both at once?

  4. Richard111 says:

    oldbrew – never thought to look at the barometer as I assumed the rate of temperature rise was far in excess of any change in local air pressure. Will provide a data copy from this site next time it happens… http://www.milfordweather.org.uk (oops, just noticed to local cloud record)

    My layman interpretation; ground cools fairly rapidly after sunset and under clear skies. When clouds arrive overhead back radiation reduces the rate of ground cooling.

    Generally, cloudy nights are not a cold as clear nights, at least where I live. 🙂

  5. Richard111 says:

    Again oops.. “NO local cloud record”. Will check to see that when dew-point and temperature are the same it will be cloudy.

  6. oldbrew says:

    ‘cloudy nights are not as cold as clear nights’ – that’s also how they see it here…

    Effects of Cloud Cover on forecasted temperatures

    Clear nights = higher pressure?
    Cloudy nights = lower pressure?

    If so, in windless conditions do the changing temps cause the pressure changes or vice versa, or is there no way of telling, or does it not matter anyway 😉
    – – –
    This probably states ‘standard’ theory but use of phrases like ‘it’s obvious that…’ doesn’t inspire confidence IMO 😦

    The effect of clouds and relative humidity

  7. Paul Vaughan says:

    The root of bad vision at the right wing department of message control services was a wave of agents infiltrating from the major western fault (a left coast group of blog and social media dark agents on a mission to guide and control their opposition…)

    “First, they will design new tests to measure why there have been so many differences between prediction models for cloud behavior so far. They will then use this research to reduce model errors and make more reliable projections.”

    …so they’ll “measure” incorrect base assumptions — amusing way back to where they started wrong.

    Relative to what baseline?
    Comparative study helps sort, but here abstract theory is being sorted, not reality.

    The product is a categorization of base assumptions (explicit array of implicit errors).
    They admit blind assumption with need to “measure” to discover own error.
    They’ll seek funding to sort and classify arrays of their own mistakes.

  8. Curious George says:

    Noctilucent clouds – the highest clouds known (75 km and up). They are supposed to be made of water ice; can’t they be made of carbon dioxide?

  9. tom0mason says:

    As I think on about clouds and all the bather about CO2, and manmade climate change, a Tom Robbins quote impinges on my thoughts…

    In fiction, when you paint yourself into a corner, you can write a pair of suction cups onto the bottoms of your shoes and walk up the wall and out the skylight and see the sun breaking through the clouds. In nonfiction, you don’t have that luxury.
    Tom Robbins

  10. AlecM says:

    Cloud aerosol physics was established in the 1960s: they got it wrong by missing a key bit of Mie Scattering. The back-reflection of the intense, narrow forward lobe from the second droplet is far more intense than for a plane wave. This effectively increases the extinction coefficient.

    The proof is the rainbow and the similar behaviour of rain clouds. It rather than small droplet radius explains why convective clouds have albedos up to ~0.9. It also means that Twomey’s albedo-optical depth relationship breaks down, why the 2nd AIE has the wrong sign and why positive feedback in hind-cating of GCMs is an artefact.

    GISS probably knows this but won’t own up. UKMO is apparently dumping CO2 warming because it derived the wrong ‘back radiation’ physics.

  11. oldbrew says:

    Climate models are not good with clouds (amongst other things):

    ‘Because of the relatively coarse spatial and temporal resolutions of the models, there are many important processes that occur on scales that are smaller than the model resolution (such as clouds and rainfall; see inset in Figure 1). These subgrid-scale processes are represented using ‘parameterizations.’ Parameterizations of subgrid-scale processes are simple formulas based on observations or derivations from more detailed process models. These parameterizations are ‘calibrated’ or ‘tuned’ so that the climate models perform adequately when compared with historical observations.’ [bold added]


  12. tom0mason says:

    Straight from the modelers (in 2012), is this draft white paper about their problem and possible resolutions…

    For other paper look here — https://www.wcrp-climate.org/grand-challenges/grand-challenges-overview
    click on a hexagon.

  13. oldbrew says:

    Why so-called climate spending is a waste of money

    A. It does little for ’emissions’
    B. It does even less for ‘the climate’
    C. Genuine causes are starved of cash
    D. Negative economic effects
    E. Etc.

  14. Richard111 says:

    Thanks for the tutorial links oldbrew. Much easier to read than the stuff I’ve been looking at. 🙂
    Will start keeping an eye on local air pressure in relation to local air temperature.
    Spent some years working in the Namib Desert and learnt the hard way about the extreme changes in temperature under clear skies between day and night while taking up astronomy out of boredom.
    No need to lie down on the cold sand, just scoop away top few inches and it’s nice and warm.
    Watch out for scorpions! Those experiences made me a sceptic of AGW since day one.

  15. suricat says:

    oldbrew says: March 26, 2017 at 9:37 am

    “Ray – DW.com is a news site not a technical science site so you can only expect generalities.”

    Quite so! However, they should also provide a link to their ‘source’. That database is actually here:


    If you want to make known your observations, you should go here:

    Well I did have the address for this, but I can’t currently find it just now. 😦

    However, I couldn’t miss your dialogue with Richard111. “Richard – in your scenario which rises first, temperature or pressure, or both at once?”

    That’s a ‘loaded question’ oldbrew. 😉

    Best regards, Ray.