Observer Comments

07:16 Tue Feb 16, 2021

On the Etymology of Cloud Names
This past weekend we got to observe an abundance of high clouds in the sky, with a thin layer of cirrostratus lingering for much of the weekend. This cloud layer helped produce a halo around the sun during the daytime hours on both Saturday and Sunday. While this appears to the observer as a thin veil that lingers high in the atmosphere, cirrostratus can be cherished for the array of optical effects it may produce, some examples including sun dogs and the aforementioned halo.
Halo viewed over the summit this past Saturday
  Saturday also brought a number of nice-looking cirrus clouds and I recalled the Latin translation of cirrus, meaning, “a lock of hair”. And cirrus clouds do look hairlike! Quite often we refer to many a cirrus cloud as “mares’ tails” in English because they actually look like a horse’s tail. The official name for this type of cloud would be cirrus uncinus; the species name uncinus meaning “hooked” in Latin.
 It was at this point that I realized that the very scientific sounding Latin names for clouds are really just apt descriptions of what the clouds actually look like, and that the aura of presenting them in a mostly dead language gives them a certain mystique. In meteorology, we often make the distinction between cumuliform and stratiform clouds; cumuliform clouds being formed in an unstable atmosphere with some element of convection, whereas stratiform clouds form in a relatively stable atmosphere, and are generally flat. Resultingly, cumuliform clouds exhibit vertical growth whereas stratiform clouds will not, maintaining their level shape. When we look at the genera of these cloud names, we see the Latin names reflecting this basic form. In Latin, cumulus means an accumulation, heap, or pile. And the word stratus comes from the past participle of the verb sternere, which means to extend, flatten, spread out, or cover with a layer. With that in mind, I’d say the Latin names seem pretty appropriate given the appearance and processes that form these clouds.
 A couple other key words will help us round out our cloud types. The word nimbus indicates a rain cloud and the prefix alto comes from the word altum, meaning height, or upper air. And with that, hopefully our cloud names sound a bit less mysterious, but perhaps no less romantic.
Our basic cloud types are as follows:
   High Clouds: Cirrus, Cirrostratus, Cirrocumulus
   Mid-level Clouds: Altostratus, Altocumulus
   Low Clouds: Cumulus, Stratocumulus, Stratus, Nimbostratus, Cumulonimbus
Of course, these are the basic cloud types, and looking at a cloud atlas will show the many different cloud species that can be observed, all described and categorized according to their Latin names.
 The next question that crossed my mind was “Why Latin?”, and as I probed into this history, I recognized that the answer was not so straightforward, and to get there would require diving into some of the historical linguistics of Latin as well as the standing of the scientific community throughout different points in time. The real answer to this question perhaps lies in the emergence of a Eurocentric scientific community that hearkens back to the days of Rome and the Latin thread that binds the various romance languages of the region. In a Europe where many languages emerged out of the remains of the Roman Empire, the scientific community eventually adopted Latin as a means for communicating in a common language. The Swedish Botanist Carl Linnaeus is generally ascribed with advocating for the use of Latin as a tool for classifying organisms in the 18th century. He chose Latin in part because of its status as a dead language; because it wasn’t commonly spoken, Latin could help science in its goal unbiased objectivity.
The British chemist and amateur meteorologist Luke Howard is generally credited with developing the prevailing cloud classification in the early 1800s that was partly inspired from Linnaeus’ own efforts to describe and categorize. We still use Howard’s classification system today.
My perception of Latin in modern society certainly leads me to more questions about its use in science and in cloud names. Certainly, Latin sounds more mysterious and romantic, and a stratus cloud perhaps conjures up more flavor than a “layer cloud” or a “sheet cloud” right?
A notion exists in academia that each field protects itself with language. Are Latin cloud names another example of this? Secrets of meteorology locked up in vernacular?  
These questions might seem a bit extreme given that the cloud types can be learned with relative ease by an astute observer, but in examining the etymology of these cloud names, it caused me to reflect on the value of having a common language in science.  
In the meantime, I’ll keep an eye out for the many interesting cloud types as they come and go, making sure to mention their names with the slick Latin rolling off my tongue.  

Nate Iannuccillo, Weather Observer/Education Specialist


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