# Custom Query (124 matches)

## Results (10 - 12 of 124)

Ticket | Resolution | Summary | Owner | Reporter | ||||
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#143 | fixed | Supplement the definitions of dimensionless vertical coordinates | davidhassell | jonathan | ||||

Description |
## 1 TitleSupplement the definitions of dimensionless vertical coordinates ## 2 ModeratorRich Signell ## 3 Purposes- Rename dimensionless coordinates as parameterized coordinates because one of them (hybrid height) is not dimensionless, and dimensionlessness is not their defining characteristic.
- Define a new attribute to supply the
`standard_name`of the dimensional coordinates computed by the formula. This may depend on the`standard_name`of one or more of the terms. Spell out the possibilities for each case in Appendix D and correct some errors.
- Point out that some vertical coordinates refer to a vertical datum surface which is described by
`grid_mapping`information.
## 4 Status quo and benefitsAt the moment it is difficult for a data user to know exactly what the computed vertical coordinate is. For example, does the ocean sigma coordinate give you a height with respect to a geopotential surface or a reference ellipsoid, and precisely what is that datum e.g. NAVD88? These changes are intended to make it easier. ## 5 Detailed proposal
Insert a new section heading "4.3.3 Parameterized Vertical Coordinate" after the sentence "The Amend the existing first paragraph of this new section from the existing text:
to read as follows:
In this section, in the sentence after Example 4.3, change "Appendix D, In section 5.6, replace the existing paragraph
with
In Appendix A, between the entries for
In Appendix A, change the Link for Rename Appendix D as "Parameterized vertical coordinates". Change the first sentence of Appendix D from "The definitions given here allow an application to compute dimensional coordinate values from the dimensionless ones and associated variables." to "The definitions given here allow an application to compute dimensional coordinate values from the parameterized (usually dimensionless) ones and associated variables."
In the first paragraph of Appendix D, change "where Append the following as a third paragraph in the preamble of Appendix D:
In the following, it will be noticed that some formula terms do not have defined standard names at the moment. Of course, names could be defined, but it is not essential because their purpose is identifiable from the Append the following paragraph to the definition of "Atmosphere natural log pressure coordinate":
Append the following paragraph to the definition of "Atmosphere sigma coordinate":
Append the following paragraph to the definition of "Atmosphere hybrid sigma pressure coordinate":
In the definition of "Atmosphere hybrid height coordinate", change "
In the definition of "Atmosphere smooth level vertical (SLEVE) coordinate", change "
In the definition of "Ocean sigma coordinate", replace "
In the definition of "Ocean s-coordinate", make the same replacements as for "Ocean sigma coordinate", and append the following paragraph:
In the definition of "Ocean sigma over z coordinate", make the same replacements as for "Ocean sigma coordinate", after "Above depth
In the definition of "Ocean double sigma coordinate", make the same replacements as for "Ocean sigma coordinate" regarding
At the end of Appendix D, insert the following table:
In the conformance document, rename "4.3.2 Dimensionless Vertical Coordinates" to "4.3.3 Parameterized Vertical Coordinate", and append these new requirements: - Where indicated by the appropriate definition in Appendix D, the
`standard_name`attributes of variables named by the`formula_terms`attribute must be consistent with the`standard_name`of the coordinate variable it is attached to, according to the appropriate definition in Appendix D. - The
`computed_standard_name`attribute is only allowed on a coordinate variable which has a`formula_terms`attribute. - The
`computed_standard_name`attribute is a string whose value must be consistent with the`standard_name`of the coordinate variable it is attached to, and in some cases also with the`standard_name`attributes of variables named by the`formula_terms`attribute, according to the appropriate definition in Appendix D.
If this ticket is agreed, the following air_pressure_at_top_of_atmosphere_model altitude_at_top_of_atmosphere_model reference_air_pressure_for_atmosphere_vertical_coordinate height_above_geopotential_datum_at_top_of_atmosphere_model height_above_geopotential_datum surface_height_above_geopotential_datum sea_surface_height_above_geopotential_datum sea_floor_depth_below_geopotential_datum sea_floor_depth_below_reference_ellipsoid height_above_sea_level Jonathan |
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#141 | fixed | Amend affiliation of one of the original authors | cf-conventions@… | jonathan | ||||

Description |
Jonathan Gregory's affiliation is given as "Hadley Centre, UK Met Office". To bring this up to date, it should be changed to "University of Reading and UK Met Office Hadley Centre." This change does not materially affect the CF convention! |
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#140 | fixed | Clarifying the role of attributes on boundary variables. | cf-conventions@… | davidhassell | ||||

Description |
## 1. Title
## 2. Moderator
## 3. Requirement
## 4. Initial Statement of Technical Proposal
- Requirements:
- The type of the bounds attribute is a string whose value is a single variable name. The specified variable must exist in the file.
- A boundary variable must have the same dimensions as its associated variable, plus have a trailing dimension (CDL order) for the maximum number of vertices in a cell.
- A boundary variable must be a numeric data type.
- If a boundary variable has
`units`or`standard_name`attributes, they must agree with those of its associated variable.`units`,`standard_name`,`axis`,`positive`,`calendar`,`leap_month`,`leap_year`and`month_lengths`attributes, they must agree exactly with those of its associated variable.
- Recommendations:
- The points specified by a coordinate or auxiliary coordinate variable should lie within, or on the boundary, of the cells specified by the associated boundary variable.
- Boundary variables should not have the
`_FillValue`or`missing_value`attributes.`_FillValue`,`missing_value`,`units`,`standard_name`,`axis`,`positive`,`calendar`,`leap_month`,`leap_year`or`month_lengths`
## 5. Benefits
## 6. Status Quo
David Hassell |

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