An Exploratory Model of Solar Influence on Stratospheric Dynamics

Authors: Alexander Ruzmaikin (1), John Lawrence (2), and Ana Cristina Cadavid (2)
Affiliation: 1) Jet Propulsion Laboratory, California Institute of Technology 2) Department of Physics and Astronomy, CSUN

We developed a simple exploratory model of the solar UV variability influence on the stratospheric dynamics based on the planetary wave-zonal flow interaction (Ruzmaikin et al., J. of Climate, 16, 1593, 2003). The model defines a system of three ordinary differential equations controlled by two parameters: the initial amplitude of planetary waves and the vertical gradient of the zonal wind. The system is found to have two major stable equilibrium states and one unstable state. Dynamical transitions between these states are caused by external influences, such as the seasonal, anthropogenic, volcanic and solar variations. We describe the changes associated with seasonal variations and with the solar variability as periodic modulations of the zonal wind gradient; the Quasi Biennial Oscillations are introduced as the modulation of the width of the interaction region. The major climatic response to these changes is seen through modulation of the number of cold and warm winters. We use the NCEP reanalysis data to compare the atmospheric flow regimes with the modeled dynamics. And we discuss the relevance of our model to the Global Climate Change.