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[CF-metadata] new standard name: lifted_index; atmosphere stability indices

From: alison.pamment at stfc.ac.uk <alison.pamment>
Date: Wed, 6 Nov 2013 14:38:36 +0000

Dear Jonathan W. , All,

I am here trying to wrap up two linked threads which have been discussed extensively and, as far as I can see, agreed.

The following names are accepted for inclusion in the standard name table and will be added at the next update.

1) temperature_difference_between_ambient_air_and_air_lifted_adiabatically_from_the_surface (K)

'This quantity is defined as the temperature difference between a parcel of air lifted adiabatically from the surface to a finishing air pressure in the troposphere and the ambient air temperature at the finishing air pressure in the troposphere. It is often called the lifted index (LI) and provides a measure of the instability of the atmosphere. The air parcel is "lifted" by moving the air parcel from the surface to the Lifting Condensation Level (dry adiabatically) and then from the Lifting Condensation Level to the finishing air pressure (wet adiabatically). Air temperature is the bulk temperature of the air, not the surface (skin) temperature. The term "surface" means the lower boundary of the atmosphere. A coordinate variable of final_air_pressure_of_lifted_parcel should be specified to indicate the specific air pressure that the temperature difference is calculated at.'

2) temperature_difference_between_ambient_air_and_air_lifted_adiabatically (K)

'This quantity is defined as the temperature difference between a parcel of air lifted adiabatically from a starting air pressure to a finishing air pressure in the troposphere and the ambient air temperature at the finishing air pressure in the troposphere. It is often called the lifted index (LI) and provides a measure of the instability of the atmosphere. The air parcel is "lifted" by moving the air parcel from the starting air pressure to the Lifting Condensation Level (dry adiabatically) and then from the Lifting Condensation Level to the finishing air pressure (wet adiabatically). Air temperature is the bulk temperature of the air. Coordinate variables of original_air_pressure_of_lifted_parcel and final_air_pressure_of_lifted_parcel should be specified to indicate the specific air pressures at which the parcel lifting starts (starting air pressure) and the temperature difference is calculated at (finishing air pressure), respectively.'

3) original_air_pressure_of_lifted_parcel (Pa)

'Various stability and convective potential indices are calculated by "lifting" a parcel of air: moving it dry adiabatically from a starting height (often the surface) to the Lifting Condensation Level, and then wet adiabatically from there to an ending height (often the top of the data/model/atmosphere). original_air_pressure_of_lifted_parcel and final_air_pressure_of_lifted_parcel are the pressure heights at the start and end of lifting, respectively.'

4) final_air_pressure_of_lifted_parcel (Pa)

'Various stability and convective potential indices are calculated by "lifting" a parcel of air: moving it dry adiabatically from a starting height (often the surface) to the Lifting Condensation Level, and then wet adiabatically from there to an ending height (often the top of the data/model/atmosphere). original_air_pressure_of_lifted_parcel and final_air_pressure_of_lifted_parcel are the pressure heights at the start and end of lifting, respectively.'

Best wishes,
Alison

------
Alison Pamment Tel: +44 1235 778065
NCAS/British Atmospheric Data Centre Email: alison.pamment at stfc.ac.uk
STFC Rutherford Appleton Laboratory
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.

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Received on Wed Nov 06 2013 - 07:38:36 GMT

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