TRACER-CAT-LANL

TRACER-CAT-LANL (Carbonaceous Aerosol Thrust)

1 July 2022 - 31 July 2022

Lead Scientist: Allison Aiken

Observatory: AMF

The TRacking Aerosol Convection interactions ExpeRiment Carbonaceous Aerosols Thrust by Los Alamos National Laboratory (TRACER-CAT-LANL) is designed to complement the larger ARM TRACER science goals to understand convective cloud lifecycles and aerosol-convection interactions. TRACER-CAT-LANL is focused on understanding the relationship between particle composition and light absorption, and the influence of water uptake on this relationship. We will determine how absorbing aerosol mixing state and optical properties change within the humid convective environment of Houston, Texas. The greater Houston area is ideal for studying these interactions, given the highly photochemically active summer environment and the vast diversity of fresh carbonaceous aerosol sources that can mix and be convectively processed. Our measurements will distinguish between the composition of black carbon (BC)-containing and BC-free particles to provide insight into how these different internally mixed particles can act as efficient cloud seeds and contribute to warm cloud invigoration. Light absorption by absorbing aerosols such as BC can increase localized warming, and in turn influence cloud formation and convective systems. However, it remains unclear the extent to which coatings on BC further enhance absorption in the atmosphere as well as the specific role that water contributes to this enhancement. For this reason, TRACER-CAT-LANL will characterize and quantify the dry and humidified optical properties and the chemical composition of carbonaceous aerosols over a period of one month in the summer during the TRACER intensive operating period (IOP). By sampling continuously and in real-time, we will characterize the relationship between chemical composition and absorption over a wide range of particle regimes and atmospheric ages. In summary, TRACER-CAT-LANL will significantly extend the core scientific capabilities of the AMF1 Aerosol Observing System (AOS) by co-deploying a complimentary suite of unique and customized aerosol instrumentation. TRACER-CAT-LANL will directly enable a more in depth understanding of the extent to which aerosols can influence the development of convective clouds by resolving the chemistry, mixing state and optical properties in greater detail.