Evaluation of Aerosols in Numerical Weather Modeling for Emerging DoD Technologies and Climate Change Studies

Aerosols play a vital role in Earth’s surface-atmosphere radiation balance whether through direct absorption
and scatter or indirectly by way of cloud formation and droplet size interactions, which in turn have inherent
radiative forcing, and directed energy implications. As Department of Defense (DoD) technologies
transition from conceptual and developmental phases to operational status, tactical decision aids that
incorporate realistic atmospheric conditions via numerical weather modeling coupled with radiative transfer
models are needed. Additionally, accurately modeling direct and indirect aerosol radiative effects have big
implications for climate change studies. Numerical weather modeling provides a sophisticated capability
for post-analysis, nowcast, and forecasted states of the atmosphere based on thousands of global
observations. Operational weather models have made recent advancements to incorporate atmospheric
aerosols, but quantifying the efficiency of aerosol modeling is limited due to available daily aerosol
observations. This research evaluates atmospheric aerosols characterized by the WRF-Chem model using
the Goddard Chemistry Aerosol Radiation and Transport (GOCART) aerosol scheme option and the Global
Aerosol Data Set (GADS). Aerosol schemes similar to GOCART in WRF-Chem are being considered for
use in various civilian and military operational global numerical weather prediction (NWP) models. The
resulting aerosol outputs are coupled to the LEEDR radiative transfer model, and calculated extinctions,
transmissions, and radiances are compared to AERONET and field measurement values collected at or near
Wright-Patterson Air Force Base. The analysis and suggestions towards improving the atmospheric model
aerosol products are presented.