The Effects of Orbital Precession on Environmental Conditions Influencing Tropical Cyclone Development and Evolution

Mark Cane has been a driving force in our understanding of the importance of the tropical Pacific on climate variations across a wide range of timescales. Building on this legacy, recent modeling studies have identified a mechanism operating on paleoclimatic timescales that has a dramatic effect on tropical Pacific climate. These studies have shown that the amplitude and phase of the seasonal cycle of the tropical Pacific cold tongue are sensitive to the precession of the equinoxes and Earth’s orbital eccentricity. The seasonal anomalies of sea surface temperature in this region relative to present-day climate can affect the large-scale environmental conditions that influence tropical cyclone development and evolution. In this presentation, a set of idealized precession simulations with a coupled atmosphere-ocean model is used to explore the sensitivity of sea surface temperature, vertical wind shear, relative humidity, static stability, and circulation over the regions in which tropical cyclones develop and evolve, and implications for paleoclimate are discussed.