Confronting Structural Uncertainty in Aerosol Effects on Climate

LAURA FIERCE, Jeffrey Johnson, Kadja Flore Gali, Joscelyne Guzman - Gonzalez, Payton Beeler, Will Cantrell, Rosa M. Fitzgerald, Matthew Dawson, Benjamin Murphy, Nicole Riemer, Pacific Northwest National Laboratory

     Abstract Number: 339
     Working Group: Aerosols, Clouds and Climate

Abstract
Aerosol effects on clouds and radiation are a large source of inter-model variability in radiative forcing among climate models. Climate-relevant aerosol properties depend critically on the distribution in size, shape, and chemical composition of particle populations that evolve in time as they are transported through Earth’s atmosphere. However, tracking such particle-level details is computationally impractical for large-scale, long-running climate simulations. Instead, aerosol modules in large-scale atmospheric models necessarily simplify the representation of particle characteristics, leading to errors in climate-relevant aerosol properties that have not been well quantified. Here we present a framework for using particle-resolved simulations of aerosol-cloud-chemistry interactions to quantify structural errors from the numerical representation of particle population. Based on this analysis, we then show how these detailed aerosol schemes can be used to improve aerosol parameterizations in large-scale models. Through this approach, we aim to inform the development of aerosol schemes that balance model accuracy with computational efficiency, while also characterizing uncertainty from reduced representations of particle populations.