The clouds above us
I’m sure you also wondered some time on the clouds above you, changing their shape, becoming more and more overwhelming, or slowly releasing their little droplets. Maybe you also found different animals taking shape or even familiar faces appearing as clouds. This is called pareidolia, a psychological phenomenon, when someone sees patterns in random data, in this case clouds. Our ancestors’ mind was quite similarly wired, therefore these transient entities have a long history in science and art. We were always fascinated by them. Let’s see what clouds are and how they are represented in different fields of the human realm.
(Pre)science
Mythos and religion
Clouds are older than humankind, therefore we can find many different representations in either mythological, pictorial or written form. One of the first example is the Akkadian mythology where clouds were perceived as the breasts of Antu, the sky goddess and the rain falling was her milk. Clouds separated heaven from earth and her son, Enlil was the one responsible for holding the waters in heaven, he was the god of the atmosphere.
There are several metaphorical and literal references to clouds in the Bible too. Some of them describing the clouds as meteorological sources of rain, dew or storm, just as the following one:
By his knowledge the deeps broke open, and the clouds drop down the dew.
Bible, Proverbs 3:20
Many other references to clouds as a form that God takes to show himself, for example to Moses. That is the most prominent example, when he gives the laws to Moses on the Mount of Sinai he comes down in a cloud to him.
Then the LORD came down in the cloud and stood there with him and proclaimed his name, the LORD.
Bible, Exodus 34:5
If we fly to the far east, we can find similar patterns, since clouds were also some kind of gateways between the human and immortal realms in chinese mythology. These were created by dragons, who breathe out air as chi, the force of life that becomes wind and as it descends forms the clouds. Their meaning was equal to luck also, probably because of the water they brought to the crops. Clouds are the union of yin and yang, often thought to be the symbols of union of female and male.
Toward science
The first scientific work aimed to understand how clouds are formed and what they are was written by Aristotle, although the authorship is disputed. Meteorologica, based on observation and intuition, was the first on the topic. It accounts for many different phenomenons, such as earthquakes, rainbows and the geology of the Earth. His explanations are anecdotal though, meaning, that he often cites others, mostly presocratic philosophers. His thoughts on spheres influenced christianity and lots of the celestial mechanics was derived from Aristotelian physics.
Science was not the main focus during the middle ages, further investigation on the formation and categorization of the clouds had to wait until 1803, when Luke Howard published his Essay on the Modification of Clouds. Howard applied the Linnean categorization system to clouds, thus set the three principal categories as cumulus, stratus and cirrus.
Howard’s essay had a great influence not only on science but also on arts, since Goethe wrote several poems dedicated to him and his classification and approached some painters and tried to commission them to get sketches of different clouds. One of them was Caspar David Friedrich, romantic painter, who declined the commission, but later started to paint clouds based on Howard’s classification system.
Art comes into play
Prior to the 19th century landscape paintings were much closer to the painters’ imagination than to reality. In the middle ages the sky as part of a painting was mostly covered with gold color referring to heaven. Later in the renaissance artists started to mimic what they saw, let it be even a cloud.
The science or classification based approach then became widespread and many painters took advantage of it giving birth to cloudscape. One of the most famous practitioners of this genre was J. M. W. Turner, whose work is somewhere between romanticism and impressionism. His paintings show uncountable versions of skies, often sunsets, over foggy land — or cityscapes.
In the 20th century artists still use their imagination, but not only that, sometimes actual weather conditions, and incorporate it in their works. A recent investigation on Munch’s most famous painting, ‘The Scream’ which depicts strange and rare clouds showed that those were actual entities, so called ‘mother of pearls’ or nacreous clouds. These form at the lower stratosphere and cause very beautiful and strange sunsets.
There are artists also in the 21st century, who approach the topic with delicate care, like Berndnaut Smilde who used custom made smoke machines to create cloud-like structures inside buildings (sometimes outside in nature) in his series called “Nimbus”. These artificial clouds were stable only for a few seconds and then disappeared into thin air. Transiency is still the substance of his artworks, the approach, the context is different from those of the past.
Only data that we will have left
In the 20th century we could see how humankind developed satellite systems that are monitoring the planet’s cloud cover continuously, sending information to data centers and thus enabling us to understand how fundamentally we changed Earth. The first of these flying dragons were sent to space back in the 1950’s, the Vanguard 2 and Tiros systems, that were using cameras for the task. As weather science and satellite precision developed, we are able to measure cloud formation in ways never seen before. The data liberation at NASA caused that raw data is available basically to anyone who is interested in meteorological measurements and can use it to derive calculations. We can now see the whole as it spins. But we also can see other things, like simulations, that predict that if we continue to exploit our planet at this pace, then within 100 to 150 years there won’t be clouds in the sky. An article was presented in Nature which says that stratocumulus clouds (that cover nearly 20% of lower latitude ocean surface and parts of the tropics, and prevent sea surface to heat up by reflecting the sunlight back to the outer space) are most likely to disappear when carbon-dioxide levels surpass 1200ppm (currently it is at 410ppm). Therefore their heat-reflective capacity will diminish, further adding fuel to a heating planet.
On the 20th of August, 2018, a young girl sat down at a square in Stockholm. She was convinced that she needs to do something within her reach. She was missing school because she thought (and still thinks) that if she doesn’t do something within her reach, she (and her generation) doesn’t have a future. She started her school strike for climate. Since then on every Friday she sat down on a square, with hundreds of thousands of her fellow strikers, and wanted the world to listen. To listen to science.
A satellite hovered over the northern hemisphere that day, taking measurements of cloud thickness, several layers within several hours. The data was sent to the Goddard Space Flight Center, where it was later incorporated to the MERRA-2 dataset. That data is available to the public, one can query it, filter for a day, location or altitude. For example 2018, August 20. For example northern hemisphere, somewhere around Stockholm. We did that, so we have the data, that we put into a data visualization tool to show those spots. The first tool that comes to mind is VisIt, which is a scientific visualization tool. It was developed at NASA, the Lawrence Livermore National Lab to exploit the power of supercomputers to create visualizations for scientific research and simulation. With VisIt it’s possible to create volumetric rendering of the given dataset, clouds in this case, and to model how those developed and changed over time. Here’s a video that shows exactly that.
But this is only one way to show those clouds, since data visualization is something that can used to iterate data over tools and environments, which sometimes leads to a different perspective. The below visualization is made with Tableau, a standard BI tool, and it shows measurement values of different altitudes next to each other, sliced, as a trellis chart.
The aim of these data vis droplets is to show the same “thing” from totally different perspectives through different viewpoints. In this case, the clouds above us.
