Abstract: Fundamental freedom existing in Ertel?s general definition of potential vorticity (PV) is used to construct an essential invariant measure in (q,??) space, where q is an ?optimal? modified PV and ? is a monotonic increasing ...

Abstract: The regional Eta workstation (WS) model with horizontal resolution of 40 km has been integrated over South America for January 2003. The NCEP?DOE Reanalysis II was used for initial and lateral boundary conditions. The ...