Ever seen a rainbow cloud looking like a giant scarf rapped around the horizon of the sky? You might have seen one going around the internet recently and wondering what it is. Well, that is called Rainbow Pileus Cloud, popularly known as The Chinese Pileus Cloud. If you thought this is fake, sorry to disappoint you. It is pretty much real. Let’s take a closer look at the The Chinese Pileus Cloud or Rainbow Pileus Cloud based on science.
“Clouds come floating into my life, no longer to carry rain or usher storm, but to add colour to my sunset sky.” — Rabindranath Tagore
Types of Clouds
There are 10 main types of clouds recognized by the World Meteorological Organization (WMO). Few of them are mentioned below:
Cirrus (Ci)
It looks like long, thin wispy white streamers high in the sky. Currys clouds are made of ice crystals. Since the shape of the clouds look like the tail of a horse they commonly known by “mare’s tails”. (UCAR, 2023)
Cirrocumulus (Cc)
Cirrocumulus clouds are small, white, puffy clouds that are typically arranged in rows or patches. They are made up of ice crystals and are found at high altitudes, typically between 5 and 12 kilometres. Cirrocumulus clouds are often seen on clear days and can indicate fair weather.
Cirrostratus (Cs)
Cirrostratus clouds are thin, sheet-like clouds that are made up of ice crystals. They are typically found at high altitudes, between 20,000 and 40,000 thousand feet. Cirrostratus clouds are often transparent, so they can be difficult to see. However, they can sometimes produce a halo around the sun or moon.
Altocumulus (Ac)
Altocumulus clouds are mid-level clouds that are typically found at altitudes of 6,500 to 20,000 feet. They are made up of water droplets and ice crystals, and they can appear in a variety of shapes, including patches, rolls, and lenticular clouds.
Altostratus (As)
Altostratus clouds are mid-level clouds that are typically found at altitudes of 6,500 to 20,000 feet. They are made up of water droplets and ice crystals, and they appear as a uniform sheet of gray or blue-gray cloud. Altostratus clouds can cover the entire sky, and they can block out the sun. They are not typically associated with precipitation, but they can sometimes produce light rain or snow.
Nimbostratus (Ns)
Nimbostratus clouds are a type of low-level, featureless cloud that is often associated with continuous precipitation. They are typically dark grey or blue-grey in colour, and they can cover the entire sky. Nimbostratus clouds are formed when warm, moist air rises and cools, causing the water vapor to condense. This type of clouds are typically found at altitudes of 2,000 to 10,000 feet.
Stratus (St)
Stratus clouds are the lowest-lying cloud type that typically found at altitudes of 2,000 to 6,500 feet. They are sometimes referred to as “fog clouds” because they can be indistinguishable from fog. Stratus clouds can be nuisance, but they can also play an important role in the water cycle.
Cumulus (Cu)
Cumulus clouds are a type of cloud that is characterized by its puffy, white appearance. They are typically found at low altitudes, and they can range in size from a few meters to several kilometres across. Cumulus clouds are formed when warm, moist air rises and cools, causing the water vapor to condense.
Cumulonimbus (Cb)
Cumulonimbus clouds are the tallest and most vertically developed clouds in the Earth’s atmosphere. They are characterized by their dark, towering appearance and their association with thunderstorms, heavy rain, hail, lightning, and sometimes tornadoes. Cumulonimbus clouds form when warm, moist air rises rapidly through the troposphere. They are the tallest clouds in the atmosphere, reaching heights of up to 16,000 meters (52,000 feet).
Lenticular (Len)
Lenticular clouds are stationary clouds that form mostly in the troposphere, typically in parallel alignment to the wind direction. They are often comparable in appearance to a lens or saucer. Nacreous clouds that form in the lower stratosphere sometimes have lenticular shapes. Formation of Lenticular clouds occur when moist air is forced to rise over a mountain or other obstacle.
Some additional less common types of clouds:
- Mammatus (Mm)
- Noctilucent (Nlc)
- Pileus (Pil)
The Chinese Pileus Cloud
The word “pileus” is Latin for “cap”. Therefore, The Chinese Pileus Cloud also known as a “mountain cap cloud” or “cap cloud,” is a meteorological phenomenon characterized by a distinct cloud formation resembling a cap or hood resting on top of a mountain peak or high-rise structure. It is a type of lenticular cloud that forms under specific atmospheric conditions.
Why Pileus Cloud Also Called The Chinese Pileus Cloud?
The inclusion of the term “Chinese” a bit misleading. Pileus Cloud can occur anywhere in the world and it is not specific to China only. In recent years, there has been a trend towards using the more general term “pileus cloud” to describe these clouds, regardless of where they are observed.
History of The Chinese Pileus Cloud
The phenomenon of the Chinese pileus cloud, or cap cloud, has a long history in Chinese culture. While there may not be a specific documented history dedicated solely to Chinese pileus clouds, their presence and significance in Chinese folklore and art showcase their cultural importance.
In traditional Chinese paintings and poetry, the depiction of misty mountains with cap-like clouds crowning their peaks is a recurrent theme. These artistic representations reflect the admiration for the beauty and mystique of cloud formations, including the pileus cloud.
Clouds, in general, hold great symbolic value in Chinese culture, representing natural forces, harmony, and the transient nature of life. They are often associated with heavenly realms and considered divine or spiritual manifestations. The imagery of clouds enveloping mountain summits is seen as a union of the earthly and celestial realisms.
Moreover, the prominence of mountains in Chinese landscape art and philosophy further contributes to the significance of pileus clouds. Mountains are regarded as sacred and embody virtues such as strength, stability, and transcendence. The presence of cap clouds atop mountain peaks adds an ethereal quality, emphasizing the sublime nature of the landscape.
While the specific history of Chinese pileus clouds as a meteorological phenomenon may not be extensively documented, their artistic and cultural prominence in Chinese heritage highlights their enduring appeal and deep-rooted symbolism within Chinese society.
Artwork About The Chinese Pileus Cloud — “Along the River During the Qingming Festival”
This is one of the famous artworks by a Chinese artist that depicts the pileus cloud phenomenon. It is also known by “Along the River During the Qingming Festival Scroll” or “Qingming Shanghe Tu”. It is available to view online here: www.comuseum.com. This masterpiece is a large-scale painting created during the Song Dynasty by the artist Zhang Zeduan.
The primary focus of the artwork is not solely on the pileus clouds, their inclusion adds to the overall atmospheric ambiance and sense of natural beauty depicted in the painting. “Along the River During the Qingming Festival” is highly regarded as a masterpiece of Chinese art and offers a glimpse into the cultural and historical aspects of Chinese society during the Song Dynasty.
Poems Mentioning The Chinese Pileus Cloud
One of the most famous poems in Chinese literature that mentions the pileus cloud is “Ascending the Stork Tower” by the Tang Dynasty poet Wang Zhihuan. While the poem does not explicitly mention the pileus cloud, it describes a cloud formation that resembles a cap or hood, which is believed to refer to the pileus cloud phenomenon.
The Science Behind The Chinese Pileus Cloud
The rainbow-like appearance of the Chinese Pileus Cloud is caused by the diffraction of sunlight through very small water droplets or ice crystals in the cloud. The Chinese Pileus Cloud can also be called as Iridescent Pileus Cloud. The term “iridescence” comes from the Latin word “iris”, which means “rainbow”. Iridescence is a colourful optical phenomenon that occurs when light is scattered by very small particles. The size and shape of the particles determine the colours that are seen.
In the case of iridescent pileus clouds, the small particles are water droplets or ice crystals. These particles are typically very uniform in size, which is why the rainbow colours are so evenly distributed. The sun must be low in the sky for iridescence to be visible. This is because the sunlight must pass through more of the atmosphere to reach the cloud, and the longer wavelengths of light (red and orange) are scattered more than the shorter wavelengths (blue and violet).
Some additional facts about the Chinese Pileus Clouds:
- They are most commonly seen in the tropics and subtropics, but they can occur anywhere in the world.
- They are often seen in association with thunderstorms, but they can also be seen in association with other types of clouds, such as cumulus clouds.
- They are typically short-lived, lasting only a few minutes to a few hours.
- They are not harmful, but they can be a sign of impending weather changes.
Do not forget to take a snap of the Chinese Pileus Cloud if you ever get lucky to see one. It is a truly rare and special sight. So, we should be appreciating the beauty of the Chinese Pileus Cloud.
