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Change proposals should include the following information as applicable.

Title

Add a new chapter to explain how to report uncertainty values that correlate with data in the file

Moderator

@user

Moderator Status Review [last updated: YYYY-MM-DD]

Brief comment on current status, update periodically

Requirement Summary

Proposing a new chapter to the CF convention to report uncertainty values in a netCDF file that correspond to a linked data variable(s). Since there is no one clear definition of an uncertainty, the proposal is flexible to accommodate many different types and shapes.

Technical Proposal Summary

Brief proposal overview

Benefits

Any data users who would like to include uncertainty values in a netCDF file with (or external) to the data file.

Status Quo

Discussion of the current state CF and other standards.

Associated pull request

#321

Detailed Proposal

I have been working on a proposal for adding uncertainties to CF for a number of years. I've presented these proposals to the CF meetings and taken into account many suggestions. In addition to the proposals to the CF community I have engaged other communities to see their needs and how to accommodate as many use cases as possible. This has culminated in a working Google Doc (https://docs.google.com/document/d/1UR0flhrEE3yw_3dKW8NpCrGymLt9idwFXJBhZ5ngX3Y/edit#) with the core proposal and examples. Most of the details of the proposal are best summed up in the Google Doc which also has permissions set to comments for anyone to add suggestions and comments.

The basic summary is to use ancillary variables to contain the uncertainty values with flexibility in how to represent the uncertainty values from scalars, to vectors, to external files, to formula to allow users to calculate uncertainty values.