In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 18, No. 16 ( 2018-08-20), p. 11813-11829
Abstract:
Abstract. Microscopic charcoal particles are fire-specific tracers, which are
ubiquitous in natural archives such as lake sediments or ice cores. Thus,
charcoal records from lake sediments have become the primary source for
reconstructing past fire activity. Microscopic charcoal particles are
generated during forest and grassland fires and can be transported over large
distances before being deposited into natural archives. In this paper, we
implement microscopic charcoal particles into a global aerosol–climate model
to better understand the transport of charcoal on a large scale.
Atmospheric transport and interactions with other aerosol particles,
clouds, and radiation are explicitly simulated. To estimate the emissions of the microscopic charcoal particles, we use
recent European charcoal observations from lake sediments as a calibration
data set. We found that scaling black carbon fire emissions from the Global
Fire Assimilation System (a satellite-based emission inventory) by
approximately 2 orders of magnitude matches the calibration data set best.
The charcoal validation data set, for which we collected charcoal observations
from all over the globe, generally supports this scaling factor. In the
validation data set, we included charcoal particles from lake sediments,
peats, and ice cores. While only the Spearman rank correlation coefficient is
significant for the calibration data set (0.67), both the Pearson and the
Spearman rank correlation coefficients are positive and significantly
different from zero for the validation data set (0.59 and 0.48, respectively).
Overall, the model captures a significant portion of the spatial variability,
but it fails to reproduce the extreme spatial variability observed in the
charcoal data. This can mainly be explained by the coarse spatial resolution
of the model and uncertainties concerning fire emissions. Furthermore,
charcoal fluxes derived from ice core sites are much lower than the simulated
fluxes, which can be explained by the location properties (high altitude and
steep topography, which are not well represented in the model) of most of the
investigated ice cores. Global modelling of charcoal can improve our understanding of the
representativeness of this fire proxy. Furthermore, it might allow past fire
emissions provided by fire models to be quantitatively validated. This
might deepen our understanding of the processes driving global fire activity.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-18-11813-2018
DOI:
10.5194/acp-18-11813-2018-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2018
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
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