One of the things I had hoped to accomplish during this semester was to add to my own ability to recognize what I see in the sky. I have added some vocabulary, but one book which has delighted me, and which wish I had started out with, and which is my second nomination for the book to use as a spine for a weather course, is The Weather Identification Handbook by Storm Dunlop. (How did he ever get that name?) It is a beautiful and clear list of cloud types and cloud names — ten genera of clouds with fourteen species and nine varieties, also three accessory forms and then six more particular forms. These, with beautiful color illustrations, are the backbone of the book.
Genera (plural of genus), species, and varieties are not altogether like their biological counterparts, however. A particular species, such as castellanus (which means turret-forming) may appear within several different genera, so that you have stratocumulus castellanus (Sc cas), altocumulus castellanus (Ac cas), cirrocumulus castellanus (Cc cas), and cirrus castellanus (Ci cas). Or, one of the accessory clouds is called pileus, which means having the form of a hood or cap above a rising air mass. Cumulus (Cu pil) and cumulonimbus (Cb pil) clouds may each have pileus forms. In other words, a species is not a specific form within a single genera; rather it is a type of form which may appear as a modification within one or more of the genera.
Another important point about cloud names is that they are, like Linnaeus’ original biological classification, based on appearance, not on origin or function. And just as, over time, biologists realized that certain similar forms were less related than other very dissimilar forms, meteorologists have realized that similar cloud forms and names do not always imply a similar source or similar weather. Names, then, are just the beginning, important because you don’t easily remember — indeed sometimes you barely notice — the things for which you have no name. It would be a fun challenge to see how many cloud types you could identify and photograph within a semester, or even within a month. But a course on weather needs to be more.
The Weather Identification Handbook also has descriptions of the major light displays, precipitation types, and some of the identifying effects of wind speed. However, because the emphasis is on weather identification, the book is not systematic in its presentation of these other things, and there is no discussion of more fundamental things belonging to climate, the larger reality in which weather is set, such as Hadley cells (you can’t see them) or the Coriolis effect. An understanding of weather requires that those topics be covered, and other sources would be necessary. Nevertheless, the principal value of Storm Dunlop’s book is that it would encourage students to look at the sky. If you look, you get curious; if you get curious you learn; if you learn, you notice much more and remember much better. It’s a beautiful little book.