Aligning to PSM nomenclature

[CommonClimate]

The ptype property is a hybrid of archiveType and proxyObservation, and cfr allows basically anything to be created. It would be preferable to align to a standard vocabulary, using the tools built for PyLiPD.

Besides consistency between reconstructions/projects, the overarching goal here is to enable setting up reasonable defaults for PSMs based on information gleaned from LiPD files.

There are two major elements:

• seasonality (see Leveraging hasSeasonality #1 )
• interpretation. The cfr PSM classes have a climate_required argument that relates specifically to a list of variable names in the prior. It would be important to figure out reasonable guesses about those based on the interpretation_variable property.