7.3
Dynamics of NAO
Fei-Fei Jin, Florida State Uinversity, Tallahassee, FL
North Atlantic Oscillation (NAO), or Arctic Oscillation (AO) is one of the most well-known prominent recurrent planetary-scale flow pattern in the stormy northern winter atmospheric circulations. To understand the dynamic origin of the unique circulation pattern of NAO, we first propose a dynamic closure for describing the Synoptic Eddy and Low-frequency Flow (SELF) two-way interaction. Based on the closure, we further propose a linear dynamic theory for NAO. By organizing transient synoptic eddies in the storm track, the low frequency flow anomalies with the NAO-like structure are preferentially reinforced. This internal dynamic self-organization of NAO results from a spatial scale-dependent positive feedback of the two-way SELF interaction, which makes NAO a leading dynamic mode of linearized atmospheric dynamic systems with respect to the observed stormy northern winter atmospheric circulations. Furthermore, the feedbacks through the ocean-atmosphere interaction can further enhance its dominance in the climate variability of long timescales.
Session 7, Midlatitude atmosphere–ocean interaction: Part II The North Atlantic
Thursday, 12 August 2004, 2:30 PM-5:15 PM, New Hampshire Room
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