Nonequilibrium Fluctuations and Climate Variability
Jeffrey Weiss
Department of Atmospheric and Oceanic Sciences, University of Colorado Boulder
Date and time:
Thursday, April 18, 2013 - 3:15pm
Abstract:
Nonequilibrium steady-states are characterized by entropy producing fluctuations. These fluctuations take the form of finite-time events with preferred lifecycles. Nonequilibrium fluctuations are typically studied in nano-scale systems, where individual fluctuations can be resolved. We show that despite the large physical scale of the climate system, aspects of natural climate fluctuations can be considered thermodynamically small due to having a small number of dynamically important degrees of freedom. The vast majority of the climate systems’ energy is stored as thermal energy in the ocean. The thermal energy of the ocean is roughly in a nonequilibrium steady-state, driven by solar heating and damped by heat transfer to the atmosphere and radiation to space. We investigate the natural variability of ocean heat content, the role of fluctuations about the nonequilibrium steady-state, and the connection to phenomena such as El Niño.