Downgradient Energy Transport and the Atmospheric Circulation

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The earth’s atmosphere operates as a heat engine, transporting energy from regions of surplus to regions of deficit. The heat transport varies remarkably smoothly with latitude despite the atmosphere having very different circulation patterns across the globe. Emerging research suggests that this heat transport appears to be well-described as a diffusive process that depends on the equator-to-pole energy contrast. If so, such a simple concept may offer a fundamental explanation for many aspects of the observed climatology and climate change (past and future). This research addresses: (i) why this conceptual model of energy transport works so well despite the highly complex atmospheric motion and (ii) the model’s ability to explain the hydrology and global distribution of temperature and atmospheric constituents of past climate states. The description of heat transport as a diffusive process is so fundamental in science that this research has the potential to significantly improve the public understanding of climate science. In addition to mentoring a young research scientist, the researchers will train a graduate student and heavily involve undergraduates in research activities.Specifically, the researchers seek to understand how the atmospheric circulation adjusts to maintain a nearly linear downgradient energy transport as the climate state changes. Using observations, they will determine how the near-linear relationship between the meridional enthalpy gradient and the atmospheric heat transport emerges as a function of space and time. Furthermore, they will perform numerical experiments that vary the dynamical transport mechanisms (e.g., changing the Earth’s rotation rate and orography) to probe the limits of the near-linear relationship. Finally, the researchers will analyze existing paleoclimate simulations, as well as carefully targeted new simulations, to evaluate how well this simple heat transport model characterizes past climates.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.