Can we see the impact of indigenous fire management on the temporal
shift in annual cycle of carbon monoxide?
Abstract
Fire is an essential global phenomenon that existed soon after the
appearance of terrestrial plants and is vital for the regeneration of
the plant species. Human activities have contributed to a changing
climate and impacted fire regimes, resulting in more intense, frequent
and severe fires. In particular, the 2019-20 bushfires in south-eastern
Australia were unprecedented in their extent and intensity. However,
human activities can also play a dominant role in regulating fire
behaviour effectively through better fire management practices. In
Northern Australia, indigenous fire managers use prescribed burns during
the early dry season to prevent large late dry season fires, which
shifts the overall temporal distribution of fire activity earlier during
the primary biomass burning season. This increasing trend of prescribed
burns has helped to significantly reduce the size and extent of the
intense late dry season fires, indicating that such fire management
practices can be effective at managing wildfires in savannas. Biomass
burning can emit many chemical species that have an impact on human
health. One of the most abundant and widely measured is carbon monoxide
(CO), whose long-term exposure can lead to potential human health risk.
CO is also a good proxy for emissions of other shorter-lived and
harder-to-measure atmospheric constituents. This study is focussed on
understanding how the earlier fire season in Northern Australia impacts
the temporal shift in annual cycle of CO. Column CO data from the
ground-based Total Carbon Column Observing Network site in Darwin will
be used together with surface measurements, complemented by the surface
mixing ratio observations from MOPITT, in order to disentangle the CO
emitted from the study region from that measured in the column from
remote emissions coupled with long-range transport. GEOS-Chem CO tagged
tracer modelling capability will be used to better understand the effect
of local fire emissions on the surface and column CO.