ISORROPIA‐MCX: Enabling Sensitivity Analysis With Multicomplex Variables in the Aerosol Thermodynamic Model, ISORROPIA

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 control strategies for pollutants that affect human health and public welfare. The multicomplex step method (MCX) is a sensitivity approach enables calculation first- higher-order sensitivities nonlinear algorithm analytical accuracy. Compared the well-known finite difference method, MCX also straight-forward compute yet does not suffer from precision errors due subtracting numbers common leading digits eliminates requirement tuning size. aerosol inorganic equilibrium thermodynamic model, ISORROPIA, which treats ammonium, chloride, nitrate, sodium, sulfate, calcium, potassium, magnesium, was augmented leverage (ISORROPIA-MCX) analyze influence total amount has concentrations partitioned into different phases. simultaneous first-order, second-order, cross-sensitivity terms in Taylor Series expansion when evaluating impact changes input parameters an output variable, increasing accuracy estimated effect functions are nonlinear. ISORROPIA encodes highly processes showcases computational advantages as well limitations fractured solution surfaces. With ISORROPIA-MCX, precursors acidity evaluated first time.