Created: 5 Feb 2024

Proposer: Jonathan Gregory & Lars Barring

Proposed Date: 2024-01-10

#270

Change Date: 5 Feb 2024, 4:18 p.m.

Term: **integral_wrt_time_of_air_temperature_deficit**

Unit: K s

Unit ref: KSXX

AMIP:

GRIB:

The phrase "integral_wrt_X_of_Y" means int Y dX. The data variable should have an axis for X specifying the limits of the integral as bounds. "wrt" means with respect to. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. The air temperature deficit is the air temperature threshold minus the air temperature, where only positive values are included in the integral. Its integral with respect to time is often called after its units of "degree-days". The air_temperature variable, which is the data variable of the integral should have a scalar coordinate variable or a size-one coordinate variable with the standard name of air_temperature_threshold, to indicate the threshold.

Change Date: 5 Feb 2024, 4:25 p.m.

Term: **integral_wrt_time_of_air_temperature_deficit**

Unit: K s

Unit ref: KSXX

AMIP:

GRIB:

The phrase "integral_wrt_X_of_Y" means int Y dX. The data variable should have an axis for X specifying the limits of the integral as bounds. "wrt" means with respect to. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. The air temperature deficit is the air temperature threshold minus the air temperature, where only positive values are included in the integral. Its integral with respect to time is often called after its units of "degree-days". The air_temperature variable, which is the data variable of the integral should have a scalar coordinate variable or a size-one coordinate variable with the standard name of air_temperature_threshold, to indicate the threshold. It is strongly recommended to include a units_metadata attribute.

Change Date: 9 Feb 2024, 3:45 p.m.

Term: **integral_wrt_time_of_air_temperature_deficit**

Unit: K s

Unit ref: KSXX

AMIP:

GRIB:

The phrase "integral_wrt_X_of_Y" means int Y dX. The data variable should have an axis for X specifying the limits of the integral as bounds. "wrt" means with respect to. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. The air temperature deficit is the air temperature threshold minus the air temperature, where only positive values are included in the integral. Its integral with respect to time is often called after its units of "degree-days". The air_temperature variable, which is the data variable of the integral should have a scalar coordinate variable or a size-one coordinate variable with the standard name of air_temperature_threshold, to indicate the threshold. 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. units_metadata="temperature: difference" means that the temperature quantity is the difference between two temperatures, so the origin of the scale is irrelevant, and only the unit of measure matters. It is strongly recommended to include the attribute units_metadata="temperature: difference".

Change Date: 23 Feb 2024, 4:23 p.m.

Term: **integral_wrt_time_of_air_temperature_deficit**

Unit: K s

Unit ref: KSXX

AMIP:

GRIB:

The phrase "integral_wrt_X_of_Y" means int Y dX. The data variable should have an axis for X specifying the limits of the integral as bounds. "wrt" means with respect to. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. The air temperature deficit is the air temperature threshold minus the air temperature, where only positive values are included in the integral. Its integral with respect to time is often called after its units of "degree-days". The air_temperature variable, which is the data variable of the integral should have a scalar coordinate variable or a size-one coordinate variable with the standard name of air_temperature_threshold, to indicate the threshold. It is strongly recommended that a variable with this standard name should have the attribute units_metadata="temperature: difference", meaning that it refers to temperature differences and implying that the origin of the temperature scale is irrelevant, because it is essential to know whether a temperature is on-scale or a difference in order to convert the units correctly (cf. https://cfconventions.org/cf-conventions/cf-conventions.html#temperature-units).