diff --git a/cf-conventions.adoc b/cf-conventions.adoc index 0ab503e7..d78364a3 100644 --- a/cf-conventions.adoc +++ b/cf-conventions.adoc @@ -1,6 +1,6 @@ include::version.adoc[] = NetCDF Climate and Forecast (CF) Metadata Conventions -Brian{nbsp}Eaton; Jonathan{nbsp}Gregory; Bob{nbsp}Drach; Karl{nbsp}Taylor; Steve{nbsp}Hankin; Jon{nbsp}Blower; John{nbsp}Caron; Rich{nbsp}Signell; Phil{nbsp}Bentley; Greg{nbsp}Rappa; Heinke{nbsp}Höck; Alison{nbsp}Pamment; Martin{nbsp}Juckes; Martin{nbsp}Raspaud; Randy{nbsp}Horne; Timothy{nbsp}Whiteaker; David{nbsp}Blodgett; Charlie{nbsp}Zender; Daniel{nbsp}Lee; David{nbsp}Hassell; Alan{nbsp}D.{nbsp}Snow; Tobias{nbsp}Kölling; Dave{nbsp}Allured; Aleksandar{nbsp}Jelenak; Anders{nbsp}Meier{nbsp}Soerensen; Lucile{nbsp}Gaultier; Sylvain{nbsp}Herlédan; Fernando{nbsp}Manzano; Lars{nbsp}Bärring +Brian{nbsp}Eaton; Jonathan{nbsp}Gregory; Bob{nbsp}Drach; Karl{nbsp}Taylor; Steve{nbsp}Hankin; Jon{nbsp}Blower; John{nbsp}Caron; Rich{nbsp}Signell; Phil{nbsp}Bentley; Greg{nbsp}Rappa; Heinke{nbsp}Höck; Alison{nbsp}Pamment; Martin{nbsp}Juckes; Martin{nbsp}Raspaud; Randy{nbsp}Horne; Timothy{nbsp}Whiteaker; David{nbsp}Blodgett; Charlie{nbsp}Zender; Daniel{nbsp}Lee; David{nbsp}Hassell; Alan{nbsp}D.{nbsp}Snow; Tobias{nbsp}Kölling; Dave{nbsp}Allured; Aleksandar{nbsp}Jelenak; Anders{nbsp}Meier{nbsp}Soerensen; Lucile{nbsp}Gaultier; Sylvain{nbsp}Herlédan; Fernando{nbsp}Manzano; Lars{nbsp}Bärring; Christopher{nbsp}Barker Version {current-version}, 31 August, 2022: See https://cfconventions.org for further information :doctype: book :pdf-folio-placement: physical @@ -47,7 +47,7 @@ include::toc-extra.adoc[] * Sylvain Herlédan, OceanDataLab * Fernando Manzano, Puertos del Estado * Lars Bärring, SMHI -* Chris Barker, NOAA +* Christopher Barker, NOAA Many others have contributed to the development of CF through their participation in discussions about proposed changes. diff --git a/ch03.adoc b/ch03.adoc index fca2185b..25f39ba7 100644 --- a/ch03.adoc +++ b/ch03.adoc @@ -60,14 +60,14 @@ When **`units`** of on-scale temperature are converted, the data may require the On-scale temperature is _unique_ among quantities in this respect; for all other quantities, zero means the same whatever the unit of measurement. For example (using **bold** to indicate a numerical data value), **0** `kilogram` is the same mass as **0** `pound`, but **0** `degC` is not the same temperature as **0** `degF` (= **-17.8** `degC`), because these two temperature **`units`** implicitly refer to measurement scales which have different origins. On the other hand, when the temperature value is a _temperature difference_, which compares two on-scale temperatures with the same origin, the value of that origin is irrelevant as it cancels out when taking the difference. -Therefore to change the **`units`** of a temperature difference requires only multiplication by a scale factor, without the addition of an offset. +Therefore to convert the **`units`** of a temperature difference requires only multiplication by a scale factor, without the addition of an offset. The **`units`** attribute does not distinguish between on-scale temperatures and temperature differences. This ambiguity also affects units of temperature raised to some power e.g. `K^2` or multiplied by other units e.g. `W m-2 K-1`, `degF/foot` or `degC m s-1`. A **`standard_name`** (<>) or **`standard_name`** modifier (<>) may clarify the intention, but they are optional. Some statistical operations described by the **`cell_methods`** attribute (<>; <>) imply that temperature must be interpreted as temperature difference, but this attribute is optional too. -In order to change the **`units`** correctly, it is essential to know whether a temperature is on-scale or a difference. +In order to convert the **`units`** correctly, it is essential to know whether a temperature is on-scale or a difference. Therefore this standard strongly recommends that any variable whose **`units`** involve a temperature unit should also have a **`units_metadata`** attribute to make the distinction. This attribute must have one of the following three values: `temperature: on_scale`, `temperature: difference`, `temperature: unknown`. The **`units_metadata`** attribute, **`standard_name`** modifier (<>) and **`cell_methods`** attribute (<>) must be consistent if present. diff --git a/history.adoc b/history.adoc index 837ab078..af2bbd8c 100644 --- a/history.adoc +++ b/history.adoc @@ -8,6 +8,7 @@ === Working version (most recent first) * {issues}481[Issue #481]: Introduce **`units_metadata`** attribute and clarify some other aspects of **`units`** +* {issues}483[Issue #483]: Add a missing author * {issues}463[Issue #463]: Convert URLs with HTTP protocol to HTTPS if available, fixed a few dead links * {issues}383[Issue #383]: Link to the CF website and deleted the Preface section * {issues}472[Issue #472]: Fix incorrect formating for some \<= symbols