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Ticket Resolution Summary Owner Reporter
#46 fixed Support for thematic data? cf-standard-names@… kfoley
Description

I am working with scientists that generate data on various aspects of climate conditions that occurred during the Pliocene. The data is used as input for climate models. I use netCDF format to distribute data and conform to CF metatdata standards when possible. One dataset we produce is a lat/lon grid of cells, each containing an integer that indicates the nature of ground cover that is predominate in that cell. There exists no continuity between these values -- 7 does not indicate an intermediate form between 6 and 8. Is there support for this thematic data in the CF standards that I have missed or is there some possibility of including it?

Thank you,

Kevin Foley USGS

#88 fixed Terms of Reference for the CF Data Model davidhassell markh
Description

Objective

The purpose of this ticket is to agree the scope and terms of reference for the CF data model.

Proposal

Scope, Terms and Conditions

  1. The CF community will adopt a data model as part of the CF Metadata Project.
  2. The data model will be a complementary resource to the:
    • CF Conventions Document
    • CF Standard Name Table
    • CF Conformance Requirements & Recommendations
    • Guidelines for Construction of CF Standard Names
  3. The data model will be maintained by the community, using the same mechanisms as are used for the conventions, conformance and standard_name documents.
  4. The data model, once it has reached v1.0, will be consistent with the CF Conventions Document.
    • This consistency will be maintained.
      • Changes to the specification should be evaluated to determine whether they are consistent with the data model: if inconsistencies exist, these should be addressed, either by altering the specification change proposal or by proposing a change to the data model.
  5. The scope of the data model is to define the concepts of CF and the relationships that exist between these concepts.
  6. The data model provides a logical abstraction of the concepts defined by CF, independent of implementation details.
  7. The data model does not define the interface to CF.

Benefits

The data model is believed to offer the following benefits providing:

  • an orientation guide to the CF Conventions Document
  • a guide to the development of software compatible with CF
  • a reference point for gap analysis and conflict analysis of the CF specification
  • a communication tool for discussing CF concepts and proposals for changes to the CF specification
#93 fixed Two new dimensionless vertical coordinate specifications for s coordinate ocean models cf-conventions@… rsignell
Description

1. Title

Two new dimensionless vertical coordinates to support ocean models

2. Moderator

Rich Signell

3. Requirement

The ocean modeling community needs two additional vertical coordinate specifications to allow modern s-coordinate model output to be CF-compliant and allow more general specification of s-coordinate model output for future development.

4. Initial Statement of Technical Proposal

The existing ocean_s_coordinate dimensionless vertical coordinate specification in CF is limited to a specific vertical stretching function and set of control parameters, while modern versions of ROMS allow for more flexible specification. Additional of these two new generalized vertical coordinate specifications would allow output from existing ROMS-derived models (and other s coordinate models) to be CF-compliant, as well as allowing more flexibility for future s_coordinate model developers and users to write and read CF-compliant model output.

Here are the proposed additions to Appendix D. Dimensionless Vertical Coordinates

Ocean s-coordinate, generic form 1

   standard_name = "ocean_s_coordinate_g1"

Definition:

   z(n,k,j,i) = S(k,j,i) + eta(n,j,i) * (1 + S(k,j,i) / depth(j,i))

    where S(k,j,i) = depth_c * s(k) + (depth(j,i) - depth_c) * C(k)

and where z(n,k,j,i) is the height, positive upwards, relative to ocean datum (e.g. mean sea level) at gridpoint (n,k,j,i); eta(n,j,i) is the height of the ocean surface, positive upwards, relative to ocean datum at gridpoint (n,j,i); s(k) is the dimensionless coordinate at vertical gridpoint (k) with a range of -1 <= s(k) <= 0, s(0) corresponds to eta(n,j,i) whereas s(-1) corresponds to depth(j,i); C(k) is the dimensionless vertical coordinate stretching function at gridpoint (k) with a range of -1 <= C(k) <= 0, C(0) corresponds to eta(n,j,i) whereas C(-1) corresponds to depth(j,i); and the constant depth_c, (positive value), is a critical depth controlling the stretching.

The format for the formula_terms attribute is

formula_terms = "s: var1 C: var2 eta: var3 depth: var4 depth_c: var5"

Ocean s-coordinate, generic form 2

   standard_name = "ocean_s_coordinate_g2"

Definition:

   z(n,k,j,i) = eta(n,j,i) + (eta(n,j,i) + depth(j,i)) * S(k,j,i)

    where S(k,j,i) = (depth_c * s(k) + depth(j,i) * C(k)) / (depth_c + depth(j,i))

and where z(n,k,j,i) is the height, positive upwards, relative to ocean datum (e.g. mean sea level) at gridpoint (n,k,j,i); eta(n,j,i) is the height of the ocean surface, positive upwards, relative to ocean datum at gridpoint (n,j,i); s(k) is the dimensionless coordinate at vertical gridpoint (k) with a range of -1 <= s(k) <= 0, s(0) corresponds to eta(n,j,i) whereas s(-1) corresponds to depth(j,i); C(k) is the dimensionless vertical coordinate stretching function at gridpoint (k) with a range of -1 <= C(k) <= 0, C(0) corresponds to eta(n,j,i) whereas C(-1) correspond to depth(j,i); and the constant depth_c, (positive value) is a critical depth controlling the stretching.

The format for the formula_terms attribute is

formula_terms = "s: var1 C: var2 eta: var3 depth: var4 depth_c: var5"

5. Benefits

The oceanographic community, especially those producing or consuming products from s coordinate models (e.g. variants and derivatives of the Regional Ocean Modeling System (ROMS)) would benefit from the addition of these two new dimensionless vertical coordinate specifications. These two new coordinates have been exercised in the Unidata Common Data Model and the Unidata NetCDF-Java Library for the last two years. It's time to add them officially to the CF Conventions.

6. Status Quo

The only option currently to store modern ROMS results as CF compliant would be to write the entire Z field as a 4D array.

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