Dear @kenkehoe 

I would encourage you to read 
https://urldefense.us/v3/__http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2013/006106.html__;!!G2kpM7uM-TzIFchu!lZZH8Apa50IIV-ZHQPUXbsCoA3pgLyGBPuCd3BHyiQUobcDr2sUpqlPxLfwBqp77DRLKswA8O4g$
  if you haven't, because there's a lot of a discussion there about the 
advantages and disadvantages of `cell_methods` and comparison with standard 
names and modifiers. Many views are expressed which are relevant to the present 
issue, including the use of `cell_methods` for the kind of purpose I've 
suggested above.

The `cell_methods` is an important part of CF metadata. It's really not an 
optional extra, because a lot of data is not the "default" cell methods, which 
implies an instantaneous point measurement for an intensive quantity. To 
describe a time-mean or spatial mean requires `cell_methods`, for instance. The 
CF standard recommends that `cell_methods` should always be included. The 
conformance document says, "If a data variable has any dimensions or scalar 
coordinate variables referring to horizontal, vertical or time dimensions, it 
should have a `cell_methods` attribute with an entry for each of these 
spatiotemporal dimensions or scalar coordinate variables," and the CF checker 
should give a warning if it's not included.

The `cell_methods` and `standard_name` are both optional in CF. They're not 
alternatives. They provide complementary parts of the metadata. Suggestions 
have been made several times for adding a further attribute that would 
encapsulate `standard_name`, `cell_methods` and other essential simple metadata 
into a single string, which could be a new extra attribute - redundant in 
content with others (which is a hazard), but convenient for searching (which is 
an advantage). This idea was elaborated in the common concepts and standard 
string discussions, both several years ago, but neither was eventually agreed. 
However, that's a separate topic from this issue.

Best wishes

Jonathan

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