Rules for Order of Species, Varieties
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I’m not sure if there is a strict set of rules for this. My policy is to go in order of generality. So you would start with the genus (e.g. Cumulus, Stratus, Cirrus, etc) and then any species (e.g. lenticularis, fibratus, etc) and then any variety (e.g. undulatus, lacunosus, radiatus, etc.). Then finally, you could add any additional accessory clouds or supplementary features (e.g.mamma, virga, praecipitatio, etc.).
This makes sense as a system, but I don’t know if it was ever actually specified. Hope that helps!
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Hi, Maria and welcome. I am not exactly sure what rules you might be looking for, but there is a Cloud Classification code which CAS has never chosen to use. Author Richard Hamblyn, a CAS member, uses the code in his books. The UK Met Office, bless them, gave me a copy of their Cloud Types for Observers handbook when they stopped printing it:
http://www.metoffice.gov.uk/media/pdf/r/i/Cloud_types_for_observers.pdf
Not all species and varieties are coded e.g. Cumulus humilis is coded CL1, Cumulus radiatus is not coded. There is a CM and a CH. You will find these in the above link.
I would have thought the ICA uses the codes but have not checked my copy yet.
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Thank you for your responses. I am looking for any published rules for adding the variety names (after genus and species are chosen) in the “correct” order. For instance, is an altocumulus stratiformis perlucidus undulatus radiatus the same (and as correct) as an altocumulus stratiformis radiatus undulatus perlucidus? Are the names added in order of dominance of the particular feature as noted by the observer?
I have not been able to find these rules in WMO documents or elsewhere. Perhaps there are no rules (who would enforce them?!) but I would like to know if possible.
Thanks!
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Maria, I am not insisting on anything, but point out that ‘order’ appears in my link in the above post. In the Introduction it says:
‘When there is more than one type of cloud of any level present, an order of priority has been arranged by WMO to determine which code figure should be used.
In this publication a separate section is devoted to the clouds of each level. At the beginning of each section a pictorial guide shows the priority of coding.’
And in the ‘Pictorial Guide CL’ the white central boxes give priority, the third box saying use one of four codes ‘whichever predominates’.
Richard Hamblyn says the codes allow for development with time, as seems true in the link.
So I suggest WMO concern for ‘order’ is more with predominance and/or time than within Varieties or Accessory Clouds & Supplementary features. You can only have one Species, so the question does not arise there.
But if you find the answer you want, do let us know.
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Eureka
Maria, you seem to have the International Cloud Atlas. In Volume 1, Part II.1.4 is a ‘Table of Classification of Clouds’. There is a footnote
‘Note 3. Species, varieties, supplementary features and accessory clouds are listed approximately in descending order of frequency of their occurrence; mother-clouds are listed in the same order as the genera’.
II.1.3.3 VARIETIES says ‘Furthermore, the same cloud may show characteristics pertaining to more than one variety. If this is the case, all the appropriate variety names are included in the name of the cloud’. It does not in this section take the opportunity to state the order of the variety names.
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By the way
My most frequently used source of cloud information is the CAS Cloud Classification chart (1). I have just realised the content of the CAS chart is the same as the ICA II.1.4 ‘Table of Classification of Clouds’ (excluding Mother Clouds) but in a much better designed format or layout.
Richard Hamblyn has a somewhat similar chart (2, 3) ‘The Cloud Species and Varieties Associated with the Ten Cloud Genera’ but which I personally do not find so helpful.
1 The Cloud Collector’s Handbook, Gavin Pretor-Pinney, 2009, pages 104, 105
2 The Cloud Book, Richard Hamblyn, 2008
3 The Met Office Pocket Cloud Book, Richard Hamblyn, 2010. This is identical in content to 2, but in the pocket size of 1.
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ICA Volume II 1987 (pictures with text)
http://library.wmo.int/pmb_ged/wmo_407_en-v2.pdf
This is a 10 MB PDF. Your Altocumulus stratiformis has five pictures, starting on page 67 (page numbers are below the picture to the left for even numbers, to the right for odd numbers). Obviously there is no ‘correct’ order used leading me to believe your suggestion ‘Are the names added in order of dominance of the particular feature as noted by the observer?’
P.S. Gavin says there is a new International Cloud Atlas coming in March 2017. So start saving your pennies. The current ICA Vol I and Vol II cost me about £75 (75GBP) from WMO in Geneva, some years ago but well worth it. A credit card helps with currency conversion. I believe there was a WMO office in USA also which might have sold the books.
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Thank you so much for your detailed detective work on the “rules” of adding variety names to cloud species. It looks like “predominance” is the key. I am amused thinking that fixing a name to a cloud only works for clouds in photographs. Observers of the clouds in real time might find that by the time they name an altocumulus stratiformis perlucidus undulatas radiatus, the cloud has changed enough to make that name obsolete!
I can hardly wait until March! For now and for free, you can find a 2016 draft of the new ICA Vol I online here http://wmo-cloudatlas.org/index.php/en/ Under the “Links” tab, you will see ICA Vol.1 and ICA Vol.2.
Again, thank you for your help on this topic.
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My error. The link below should take you to the 2016 draft, which begins with the preface to the 1939 edition of the ICA and includes the prefaces of the 19566, 1975, and 1987 editions (no photos). There are quite a few blank pages for the new preface and other material still being added but what is useful is the areas, highlighted in yellow by the ICA editors, showing new material, including asperitas!
https://www.wmo.int/pages/prog/www/IMOP/ICA/2016_First_Section_draft1_en.pdf
Maria
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