• Geoff Stanley,
  • Trevor McDougall

Description of Research Project:

Since the 1940’s, the key concept in large-scale atmospheric and oceanic dynamics is that of potential vorticity (PV).  As a single scalar field, PV captures both dynamics and thermodynamics by combining three fundamental conservation laws — those for mass, momentum, and potential enthalpy — into one all-encompassing conservation law. 

The original 1942 definition of PV is valid only for single-component fluids such as dry air or fresh water, where the density is determined purely from the temperature and pressure.  Unfortunately, variations of moisture in the atmosphere and variations of salinity in the ocean break the PV conservation law.  Various definitions have been proposed for moist air PV and salt water PV, each associated with an approximate conservation law of varying quality. 

This project defines a new PV that naturally generalizes the 1942 PV to multicomponent fluids such as these.  We will assess the quality of its conservation law in both oceanographic and atmospheric datasets, comparing against those for previous definitions of PV. 

Contact details:

  • Geoff Stanley ( )
  • Trevor McDougall ( )