Mid-Atlantic Section Fall Meeting 2020
Volume 65, Number 20
Friday–Sunday, December 4–6, 2020;
Virtual
Session B03: Atmospheric Chemistry and Aerosols I
2:00 PM–4:00 PM,
Friday, December 4, 2020
Chair: Ogochukwu Enekwizu, NJIT
Abstract: B03.00003 : Wildfires and Their Contribution to Climate Change*
3:12 PM–3:48 PM
Preview Abstract
Abstract
Author:
Arthur Sedlacek
(Brookhaven National Laboratory)
Aerosols emitted from wildfires and agricultural burns, collectively
referred to as biomass burning aerosols (BBA), perturb Earth's climate
through ``direct'' effects (scattering and absorption of incoming shortwave
radiation), ``semi-direct'' effects (evaporation of cloud drops and
modification of atmospheric dynamics), and ``indirect'' effects (influencing
cloud formation and precipitation). These events are an important source of
emitted primary and secondary aerosol particles providing an estimated
50{\%} of anthropogenically-influenced fine carbonaceous particles and
\textasciitilde 40{\%} of the global atmospheric inventory of black carbon
(BC) -- a warming agent second only to CO$_{\mathrm{2}}$. Additionally,
these events generate light-absorbing organic compounds, known as brown
carbon (BrC). The overall effect of these BBA emissions on the atmospheric
radiation balance, either forcing the atmosphere to heat or cool, depends on
their abundance, cloud-forming activity, and complex refractive index. Their
climate forcing impacts are governed by these particle properties and their
temporal and spatial extents during their lifecycle. By combining aircraft
observations on the near-source evolution (\textless 5 hrs) of BBA particles
with measurements on very aged (1-2 weeks) BBA plumes that have been
transported 1000's of kilometers across oceans to other continents, we can,
for the first time, begin to examine how biomass burn aerosols change
throughout their lifecycle.
The lifecycle of BB aerosols from near-source to near-global extents will be
discussed, focusing on the evolution of their chemical, microphysical, and
optical properties. Primarily utilizing measurements of black carbon
containing particles, we track observed changes in BBA particle properties
that provide insights into the processes affecting them as their
environments change from local emission through long range transport.
I will first introduce the importance and associated complexities of biomass
burning. Next I will briefly discuss how measurements of these events are
conducted and how uniquely combining different measurements can provide new
insights into how atmospheric processing can alter the compositional,
microphysical and optical properties of BBA particles. Finally, I will give
an overview of the lifecycle of BBA particles and their properties.
*This research was performed under sponsorship of the U.S. DOE Office of Biological & Environmental Sciences (OBER) Atmospheric Research Program (ASR) under contract DE-SC0012704.