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Joint distributions of potential vorticity and inert trace constituent in CCM2 and UW θ‐σ model simulations
Author(s) -
Zapotocny Tom H.,
Lenzen Allen J.,
Johnson Donald R.,
Reames Fred M.,
Politowicz Philip A.,
Schaack Todd K.
Publication year - 1996
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/96gl02298
Subject(s) - isentropic process , potential vorticity , isobaric process , vorticity , sigma , trace (psycholinguistics) , joint probability distribution , statistical physics , thermodynamics , physics , meteorology , mathematics , vortex , statistics , quantum mechanics , linguistics , philosophy
This letter describes an experiment that examines the ability of the University of Wisconsin (UW) hybrid isentropic‐sigma (θ‐σ) and sigma (σ) coordinate models and the NCAR Community Climate Model 2 (CCM2) to transport and conserve the joint distributions of isentropic potential vorticity (P θ ) and a source‐free inert trace constituent related to the initial distribution of P θ called proxy ozone (O 3 ), during 10‐day isentropic integrations. Under the idealized conditions of this experiment, the governing equations for the atmospheric continuum require that the initial joint distribution of P θ and O 3 be conserved, thereby establishing a test of model accuracy from statistical comparisons of paired values of O 3 and P θ . Any decrease in the initial correlation of unity of P θ and O 3 after integration is an objective measure of a model's skill. Results show that correlation coefficients for the UW θ‐σ model remain higher than those from CCM2 and the UW σ model, demonstrating an inherent advantage in the simulation of trace constituent transport relative to dynamical processes in isentropic versus sigma coordinate models.