Open AccessPiecewise Potential Vorticity Inversion and Vortex Interaction
Author(s) -
Joseph Egger
Publication year - 2009
Publication title -
journal of the atmospheric sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.853
H-Index - 173
eISSN - 1520-0469
pISSN - 0022-4928
DOI - 10.1175/2009jas3079.1
Subject(s) - vortex , vorticity , potential vorticity , piecewise , inversion (geology) , mathematics , physics , meteorology , mathematical analysis , geology , seismology , tectonics
Piecewise potential vorticity inversion (PPVI) aims at an interpretation of the interaction of potential vorticity (PV) anomalies q. The total flow domain D is divided into subdomains D1 and D2 with q1 and q2 as PV anomalies. PPVI estimates the height tendency in D that results if q is transported by the winds obtained by an inversion of a PV field with q = q1 in D1 and q = 0 in D2. Tests compare the actual height tendency to that obtained via PPVI. This method is applied to the interaction of vortices in quasigeostrophic shallow water, a problem generally accepted as a paradigm for PPVI. Indeed, results are excellent for vortex pairs. Combinations of more vortices, including vortex clusters akin to Rossby waves, are also exposed to tests. The utility of PPVI tendencies depends strongly on the arrangement of the vortices in that case. Very good agreement is found as well as cases with quite low skill. The reasons for this scatter are discussed and a dynamic interpretation of PPVI is proposed.