High-detail aerosol simulation for intercomparison with spatially-distributed and pointwise field measurements and global models

This project will develop a new aerosol

aerosols

Small particles or droplets, such as wildfire smoke, volcanic gases, or salty sea spray, that float in the air. They are emitted by both natural events and human activities.

Source: NASA Global Climate Change Source

model (the Weather Research and Forecasting-Particle-resolved Monte Carlo-Large Eddy Simulation, WRF-PartMC-LES) that combines particle-level aerosol representation (from the existing PartMC model) with high spatial resolution (from the existing WRF-LES model), and run simulations at different horizontal and vertical resolutions for ARM/ASR measurement campaigns and facilities (focusing on the data from the Carbonaceous Aerosol and Radiative Effects Study (CARES) and the Holistic Interactions of Shallow Clouds, Aerosols, and Land-Ecosystems (HI-SCALE) field campaigns and Southern Great Plains (SGP) atmospheric observatory). The goal of this research effort is to fundamentally advance our climate modeling capabilities, with a focus on understanding the aerosol impacts on climate and the uncertainties that exist in current and future models.

This new WRF-PartMC-LES model will be used to systematically quantify the impact of spatial resolution and sub-grid processes on the accuracy of aerosol models by comparing between different spatial resolutions (e.g., 100 m LES grids versus 4 km Reynolds-averaged Navier–Stokes (RANS) grids) and different aerosol representations (high-detail, particle-resolved PartMC-MOSAIC (Particle Monte Carlo model-Model for Simulating Aerosol Interactions and Chemistry) versus lower- detail, MAM3 (3-mode version of the modal aerosol module)), and validating with ARM/ASR data (especially distributed data sources such as POPSNet (the Portable Optical Particle Spectrometer Network) at SGP). To guide the development of this new modeling framework, this project will focus on three target aerosol processes: dry deposition, secondary organic aerosol phase transitions, and soot restructuring. During development we will focus on three target data sources: the CARES and HI-SCALE campaigns, and the SGP atmospheric observatory (including POPSnet).

Building on previous DOE-funded research, this project will innovate in three fundamental ways.
It will address two central problems of aerosol science: how do aerosols vary across space (spatial heterogeneity, including sub-kilometer scales) and how does this interact with the evolution of particle size and composition?
It will address two corresponding problems of aerosol modeling: what errors (structural uncertainty) are introduced by having insufficient spatial resolution (including sub-kilometer scales), and how does this interact with errors caused by a limited ability to resolve aerosol size and composition (e.g., due to a small number of size bins or modes for the aerosol).
It will create an integrated model hierarchy to take process-level research within ASR and rigorously translate it into models ready for integration into Earth system models

earth system model (ESM)

A model that simulates how chemistry, biology, and physical forces work together. These models are similar to, but much more comprehensive than, global climate models.

Source: U.S. Department of Energy Source

such as the DOE’s Energy Exascale Earth System Model (E3SM),

Energy Exascale Earth System Model (E3SM)

The Energy Exascale Earth System Model (E3SM) project includes Earth System Models, simulations, and predictions to investigate energy-relevant science using code optimized for DOE's advanced supercomputers.

Source: NVCL Web Page Source

with full quantification of the structural uncertainty introduced by limited spatial resolution and composition representation.

This project focuses on aerosols, and lays the foundations for work that considers spatially-heterogeneous aerosols and clouds together.

By creating a new LES-resolution particle-resolved model (WRF-PartMC-LES) that bridges to the existing WRF-PartMC and WRF-Chem models at coarser scales, we will build an integrated model hierarchy to understand aerosol uncertainties. Not only will this address key science and modeling questions, but it will be an important capability for future ASR research, including planning and analyzing data from future campaigns where spatial heterogeneity is a focus (e.g., the upcoming Southeast U.S. (SEUS) field campaign), guiding the development of robust sub-grid parameterizations, and evaluating ASR aerosol process research.