Mechanical and Civil Engineering Seminar

Mechanical and Civil Engineering Seminar Series

Title: Building frameworks for physics missing from climate models

Abstract: Climate model errors, e.g., from missing or poorly represented physics, preclude the accuracy of their projections. I will present progress towards developing frameworks for such physics in atmospheric and cryospheric dynamics informed by field and satellite data. The first part of the talk will highlight contributions to some key engineering challenges of climate and the environment by using the laboratory as an analogue for cryospheric processes and modeling naturally-occurring inhibitors of climate impacts. 'Mélanges' of calved icebergs and sea ice form in fjords and have been hypothesised to buttress marine-terminating glaciers and inhibit calving. I will examine the influence of cohesion-by-freezing in a laboratory analogue for mélange and discuss other parts of the cryosphere, such as sea ice and subglacial processes, for which freezable laboratory analogues can be designed and combined with theory to tie small-scale processes to large-scale behaviour, an enduring modeling challenge. The second part of the talk highlights a rather different approach and different context for dynamics at multiple scales. Multiscale asymptotic methods are applied to a stratified turbulent setup to propose parameterizations of turbulent diffusion coefficients. Future research directions applying these methods to scale-separated physics in the stratosphere will be discussed. The talk's final vignette is motivated by the increasing frequency and intensity of wildfires. I will present progress towards developing a simple model for the self-organization of wildfire smoke from the surface to the stratosphere, with a long term aim of real time detection of extreme wildfire weather. My talk will conclude with an outlook on opportunities I see in the landscape of research at the interface of engineering, climate, and the environment.

Bio: Kasturi Shah is a McDonnell Foundation Postdoctoral Fellow at the University of Cambridge in the Department of Applied Mathematics and Theoretical Physics. Running themes of her work include the study of how coupled interactions can produce observed behavior in the cryosphere and atmosphere and how dynamical self-organization emerges in geophysical systems. She moved to Cambridge from the other Cambridge where she completed her PhD at the Massachusetts Institute of Technology.

NOTE: At this time, in-person Mechanical and Civil Engineering Lectures are open to all Caltech students/staff/faculty/visitors.