CAREER: The Hydrological Cycle and the Maintenance of the Atmospheric Circulation: Entropy Perspective

New York University, New York NY

Investigators

Abstract

The maintenance of the atmospheric circulation requires a continuous production of kinetic energy to balance frictional dissipation. Traditionally, the atmosphere is described as acting as a heat engine that produces kinetic energy by transporting potential energy in the form of heat from warm to cold regions. However, recent studies indicate that moist processes such as diffusion of water vapor, irreversible phase transition and precipitation are responsible for most of the irreversible entropy (a measure of the potential energy unavailable for conversion to motion or kinetic energy) in the atmosphere. It is argued that, as the atmosphere acts as a dehumidifier, its ability to function as a heat engine is reduced: the hydrological cycle severely limits the amount of kinetic energy produced by the atmospheric circulation. This research investigates the connection between the hydrological cycle and the intensity of the circulation. The research component follows three main directions: the development of a new theoretical framework based on the entropy and available potential energy budgets in open systems and transients, the application of this framework in case studies, including shallow convection, hurricanes, and midlatitude storm systems, and the analysis of the global entropy budget, focusing on the impacts of climate change on entropy production and kinetic energy dissipation. Intellectual merit: The Principal Investigator will (1) develop a new perspective on the maintenance of the general circulation of the atmosphere and its relationship to the hydrological cycle, (2) assess the impacts of future climate change on the number and intensity of extreme events such as thunderstorms and hurricanes. Broader Impacts: Two new courses (one undergraduate and one graduate) on atmospheric thermodynamics and climate will be introduced. These courses will directly involve students in some of the research activities, including high-end simulations of atmospheric flows. A textbook on irreversible thermodynamics in the atmosphere will be prepared. It is expected that this project will provide a research topic for graduate student.