Simulations of the February 1979 stratospheric sudden warming: model comparisons and three-dimensional evolution

Abstract

The ECM (entropy coordinate model) produces a more realistic recombination and recovery of the polar vortex in the midstratosphere after the warming, due mainly to better conservation properties for Rossby-Ertel potential vorticity in this model. Another advantage of the ECM is the automatic increase in vertical resolution near baroclinic zones. Comparison of SMM (Stratosphere-Mesosphere Model) simulations with forecasts performed using the University of California, Los Angeles general circulation model confirms the previously noted sensitivity of stratospheric forecasts to tropospheric forecast and emphasizes the importance of adequate vertical resolution in modeling the stratosphere. -from Authors