Implementing a high-resolution dust emissions scheme in Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and its implications for the air quality

Abstract:

Mineral dust aerosols play an important role in Earth’s radiation budget, cloud nucleation, marine and terrestrial biogeochemical cycles, ambient air quality, and human health. Due to large variations in aerosol size, physical, and chemical properties and their interactions with the atmosphere, air quality models often show large uncertainties in dust aerosol budget. To address some of the uncertainties in dust simulation, a high resolution (30 m x 30 m spatial resolution) state of art dust emission inventory is developed over the southwestern US. A new capability is developed to map these emissions at different resolutions and ingest these emissions offline in the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) to simulate their transport and dispersion. We are using these emissions in a two-domain setup at 3 km and 600 m grid spacing over the southwestern United States (US) with a focus on the Salton Sea area in California. Mass concentrations of particles of aerodynamic diameter less than 10 µm (PM₁₀) simulated from WRF-Chem are being compared with the in-situ PM₁₀ observations in the study area. A new parameterization scheme is also being developed to calculate the dust emissions online within WRF-Chem to capture the impact of short-term (less than 1 hour) variations in dust emissions due to varying meteorological conditions. Detailed results from implementing high resolution emissions, comparison with surface observations, and the details of parameterization scheme will be discussed in the presentation.