Abstract: The physical state of atmospheric particles is largely unknown despite its importance for air quality and for the aerosol's climate forcing. This lack in knowledge is due to the difficulty in determining aerosol phases, a task that is complicated by bifurcations between equilibrium and metastable branches of hygroscopic growth. With a very few exceptions, current models often fail to predict the phase state and chemical composition of atmospheric particles.
In this talk, we review problems arising from important issues related to mathematical modeling of physical state of atmospheric aerosol particles, and propose computational methods to address them effectively. We present examples to illustrate how the problem of finding liquid-liquid equilibrium is related to the convexification of a function, how the phase stability is ensured by certain inertia property of the KKT matrix, how a global minimum can be located using primal-dual active-set/interior-point methods, and how the hygroscopic hysteresis effect of the relative humidity history is modeled by a system of algebraic-differential equations. To conclude, we introduce our EPA project on aerosol modeling and application to 3D air quality models, and give the main direction for the future research.
Future talks in Scientific Computing Seminar
Nov. 18: E.W. Sachs, Department of Mathematics, Virginia Tech.
Nov. 22: P. Bochev: Sandia National Laboratories.
Nov. 23: O. Pironneau, Universite Pierre-et-Marie-Curie, France.
This seminar is easily accessible to persons with disabilities. For more information or for assistance, please contact the Mathematics Department at 743-3500.