The Role of Acetone on Global Atmospheric Composition
- Alexandra Rivera,
- Kostas Tsigaridis,
- Gregory Faluvegi
Abstract
Acetone is an abundant volatile organic compound with important
influence on ozone and atmospheric self-cleaning processes. The budget
of acetone is influenced by various sources and sinks. Direct sources
include anthropogenic, terrestrial vegetation, oceanic, and biomass
burning emissions, while chemistry forms acetone from other compounds.
Sinks include deposition onto the land and ocean surfaces, as well as
chemical loss. The GISS Earth System Model, ModelE, is capable of
simulating a variety of Earth system interactions. Previously, acetone
had a very simplistic representation in the ModelE chemical scheme. This
study assesses a greatly improved acetone tracer scheme, in which
acetone's sources, sinks and atmospheric transport are now tracked in 3
dimensions. Extensive research was conducted to assess how well past
literature supported the new global acetone budget. Anthropogenic,
vegetation, biomass burning, and deposition schemes fit well with
previous studies. While their net fluxes were well-supported, source and
sink terms for chemistry and the ocean were overestimated and
underestimated, respectively. In iterations of the chemistry scheme, it
was found that the production of acetone from hydrocarbon oxidation is a
strong leverage to the overall chemical source. Spatial distributions
reveal that ocean uptake of acetone dominates northern latitudes, while
production is mainly in mid-southern latitudes. Ocean surface conditions
influence ocean-acetone interactions and will be considered when
modifying the ocean scheme in future work. The seasonality of
acetone-related processes was also studied in conjunction with field
measurements around the world. These comparisons show promising results,
but have shortcomings at urban locations, since the model's resolution
is too coarse to capture high-emission areas. Overall, an analysis of
the acetone budget aids the development of the tracer in the GISS
ModelE, a crucial step to parameterizing the role of acetone in the
atmosphere.