# Calculating Potential Vorticity of a Parcel of Air

1. Oct 7, 2012

### Johnball96

Hello,

I am trying to calculate the potential vorticity (PV) in units (PVU) of thousands of different parcels of air on varying spatial and temporal scales. Variables available are as follows;

parameter Unit Format Precision Default value :

1 date yyyymmdd I8.8 0 99999999
2 time hhmmss I6.6 0 999999
3 latitude deg F6.2 0.01 -99.99
4 longitude deg F7.2 0.01 -999.99
5 baro altitude m F8.1 0.3 -99999.9
6 radio altitude m F7.1 0.1 -9999.9
7 pressure Pa I7 10 -999999
8 A340. stat. temp. deg C F6.2 0.25 -99.99
9 A340.air.speed m/s F7.2 0.01 -999.99
10 A340.ground.speed m/s F7.2 0.01 -999.99
11 wind direction deg F7.2 0.01 -999.99
12 wind speed m/s F7.2 0.01 -999.99
13 ozone mixing ratio ppbv I5 1 -9999
14 static temp. deg C F5.1 0.1 -99.9
15 Relative humidity % F6.1 0.1 -999.9
16 RH validity 0,1,2,3 I2 0 9
17 RH uncertainty % I3 1 -99
18 H2O mixing ratio g/kg F7.3 0.01 -99.999
19 CO mixing ratio ppbv F6.0 1 -9999.
20 NOy mixing ratio ppbv F6.2 0.01 -99.99
21 NO mixing ratio ppbv F6.2 0.01 -99.99
22 NOx mixing ratio ppbv F6.2 0.01 -99.99
23 NOy uncertainty ppbv F6.2 0.01 -99.99
24 NOy validity 0-63 I2 0 -9

Is it possible to calculate the potential vorticity of an individual air particle?

John

2. Oct 7, 2012

### Studiot

What, please, is a potential vorticity?

The two terms are used specifically in mutually exclusive circumstances.

3. Oct 7, 2012

### Johnball96

I am trying to uses potential vorticity (PV) as a meteorological tool to isolate Tropospheric airmass from those of stratospheric origin. Many papers discuss calculation of PV as a good technique for this.

McIntyre (2012) describe PV as "the constancy on a fluid particle... central to stratified, rotating fluid dynamics". I think the idea is that there is the potential for creating vorticity at different latitudes where adiabatic variance in isentropically frictionless separated layers

there is a potential for creating vorticity by changing latitude and by adiabatically
changing the separation of isentropic layers.

PV = g(-∂θ/∂p)ζ

where g is gravity, ζ is the component of absolute vorticity normal to an isentropic surface, and -∂θ/∂p is the static stability.