Created: Feb. 5, 2024

Proposer: Jonathan Gregory & Lars Barring

Proposed Date: 2024-01-10

#270

Change Date: Feb. 5, 2024, 4:29 p.m.

Term: **product_of_lagrangian_tendency_of_air_pressure_and_air_temperature**

Unit: K Pa s-1

Unit ref: KPAS

AMIP: mpwapta

GRIB:

The phrase "product_of_X_and_Y" means X*Y. The phrase "tendency_of_X" means derivative of X with respect to time. The Lagrangian tendency of a quantity is its rate of change following the motion of the fluid, also called the "material derivative" or "convective derivative". The Lagrangian tendency of air pressure, often called "omega", plays the role of the upward component of air velocity when air pressure is being used as the vertical coordinate. If the vertical air velocity is upwards, it is negative when expressed as a tendency of air pressure; downwards is positive. Air pressure is the force per unit area which would be exerted when the moving gas molecules of which the air is composed strike a theoretical surface of any orientation. Air temperature is the bulk temperature of the air, not the surface (skin) temperature.

Change Date: Feb. 5, 2024, 4:42 p.m.

Term: **product_of_lagrangian_tendency_of_air_pressure_and_air_temperature**

Unit: K Pa s-1

Unit ref: KPAS

AMIP: mpwapta

GRIB:

The phrase "product_of_X_and_Y" means X*Y. The phrase "tendency_of_X" means derivative of X with respect to time. The Lagrangian tendency of a quantity is its rate of change following the motion of the fluid, also called the "material derivative" or "convective derivative". The Lagrangian tendency of air pressure, often called "omega", plays the role of the upward component of air velocity when air pressure is being used as the vertical coordinate. If the vertical air velocity is upwards, it is negative when expressed as a tendency of air pressure; downwards is positive. Air pressure is the force per unit area which would be exerted when the moving gas molecules of which the air is composed strike a theoretical surface of any orientation. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. It is strongly recommended to include a units_metadata attribute.

Change Date: Feb. 9, 2024, 3:32 p.m.

Term: **product_of_lagrangian_tendency_of_air_pressure_and_air_temperature**

Unit: K Pa s-1

Unit ref: KPAS

AMIP: mpwapta

GRIB:

The phrase "product_of_X_and_Y" means X*Y. The phrase "tendency_of_X" means derivative of X with respect to time. The Lagrangian tendency of a quantity is its rate of change following the motion of the fluid, also called the "material derivative" or "convective derivative". The Lagrangian tendency of air pressure, often called "omega", plays the role of the upward component of air velocity when air pressure is being used as the vertical coordinate. If the vertical air velocity is upwards, it is negative when expressed as a tendency of air pressure; downwards is positive. Air pressure is the force per unit area which would be exerted when the moving gas molecules of which the air is composed strike a theoretical surface of any orientation. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. 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. It is strongly recommended to include the attribute units_metadata.

Change Date: Feb. 23, 2024, 4:15 p.m.

Term: **product_of_lagrangian_tendency_of_air_pressure_and_air_temperature**

Unit: K Pa s-1

Unit ref: KPAS

AMIP: mpwapta

GRIB:

The phrase "product_of_X_and_Y" means X*Y. The phrase "tendency_of_X" means derivative of X with respect to time. The Lagrangian tendency of a quantity is its rate of change following the motion of the fluid, also called the "material derivative" or "convective derivative". The Lagrangian tendency of air pressure, often called "omega", plays the role of the upward component of air velocity when air pressure is being used as the vertical coordinate. If the vertical air velocity is upwards, it is negative when expressed as a tendency of air pressure; downwards is positive. Air pressure is the force per unit area which would be exerted when the moving gas molecules of which the air is composed strike a theoretical surface of any orientation. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. It is strongly recommended that a variable with this standard name should have a units_metadata attribute, with one of the values "on-scale" or "difference", whichever is appropriate for the data, because it is essential to know whether the temperature is on-scale (meaning relative to the origin of the scale indicated by the units) or refers to temperature differences (implying that the origin of the temperature scale is irrevelant), in order to convert the units correctly (cf. https://cfconventions.org/cf-conventions/cf-conventions.html#temperature-units).