ISORROPIA‐MCX: Enabling Sensitivity Analysis With Multicomplex Variables in the Aerosol Thermodynamic Model, ISORROPIA
Name
Earth and Space Science - 2023 - Berman - ISORROPIA‐MCX Enabling Sensitivity Analysis With Multicomplex Variables in the.pdf
Description
Published version
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567.65 KB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Berman, Bryan
Capps, Shannon L
Sauvageau, Isaiah
Gao, Eric
Eastham, Sebastian D
Russell, Ryan P
Date Issued
June 26, 2023
Journal
Earth and Space Science
Publisher
American Geophysical Union
Citation
Berman, B., Capps, S. L., Sauvageau, I., Gao, E., Eastham, S. D., & Russell, R. P. (2023). ISORROPIA-MCX: Enabling sensitivity analysis with multicomplex variables in the aerosol thermodynamic model, ISORROPIA. Earth and Space Science, 10, e2022EA002729.
Version
Final published version
Abstract
Sensitivity analysis with atmospheric chemical transport models may be used to quantify influences of specific emissions on pollutant concentrations. This information facilitates efficient environmental decision‐making regarding emissions control strategies for pollutants that affect human health and public welfare. The multicomplex step method (MCX) is a sensitivity analysis approach that enables calculation of first‐ and higher‐order sensitivities of a nonlinear algorithm with analytical accuracy. Compared to the well‐known finite difference method, the MCX method is also straight‐forward to compute yet does not suffer from precision errors due to subtracting numbers with common leading digits and eliminates the requirement of tuning the step size. The aerosol inorganic equilibrium thermodynamic model, ISORROPIA, which treats ammonium, chloride, nitrate, sodium, sulfate, calcium, potassium, and magnesium, was augmented to leverage the multicomplex step method (ISORROPIA‐MCX) to analyze the influence that the total amount of a pollutant has on concentrations partitioned into different phases. This enables simultaneous calculation of the first‐order, second‐order, and cross‐sensitivity terms in the Taylor Series expansion when evaluating the impact of changes in input parameters on an output variable, increasing the accuracy of the estimated effect when the functions are nonlinear. ISORROPIA encodes highly nonlinear processes which showcases the computational advantages of the multicomplex step method as well as the limitations of the approach for fractured solution surfaces. With ISORROPIA‐MCX, the influence of total concentrations of aerosol precursors on aerosol acidity are evaluated with cross‐sensitivity terms for the first time.
MIT Department
Massachusetts Institute of Technology. Laboratory for Aviation and the Environment
Terms of Use
Creative Commons Attribution-NonCommercial-NoDerivatives
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DOI of Published Version
https://doi.org/10.1029/2022ea002729
