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| Titel |
Biomass burning contribution to black carbon in the Western United States Mountain Ranges |
| VerfasserIn |
Y. H. Mao, Q. B. Li, L. Zhang, Y. Chen, J. T. Randerson, D. Chen, K. N. Liou |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 21 ; Nr. 11, no. 21 (2011-11-11), S.11253-11266 |
| Datensatznummer |
250010186
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| Publikation (Nr.) |
 copernicus.org/acp-11-11253-2011.pdf |
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| Zusammenfassung |
| Forest fires are an important source to
carbonaceous aerosols in the Western United States (WUS). We quantify the
relative contribution of biomass burning to black carbon (BC) in the WUS
mountain ranges by analyzing surface BC observations for 2006 from the
Interagency Monitoring of PROtected Visual Environment (IMPROVE) network
using the GEOS-Chem global chemical transport model. Observed surface BC
concentrations show broad maxima during late June to early November.
Enhanced potassium concentrations and potassium/sulfur ratios observed
during the high-BC events indicate a dominant biomass burning influence
during the peak fire season. Model surface BC reproduces the observed
day-to day and synoptic variabilities in regions downwind of but near urban
centers. Major discrepancies are found at elevated mountainous sites during
the July-October fire season when simulated BC concentrations are biased low
by a factor of two. We attribute these low biases largely to the
underestimated (by more than a factor of two) and temporally misplaced
biomass burning emissions of BC in the model. Additionally, we find that the
biomass burning contribution to surface BC concentrations in the USA likely
was underestimated in a previous study using GEOS-Chem (Park et al., 2003),
because of the unusually low planetary boundary layer (PBL) heights in the
GEOS-3 meteorological reanalysis data used to drive the model. PBL heights
from GEOS-4 and GEOS-5 reanalysis data are comparable to those from the
North American Regional Reanalysis (NARR). Model simulations show slightly
improved agreements with the observations when driven by GEOS-5 reanalysis
data, but model results are still biased low. The use of biomass burning
emissions with diurnal cycle, synoptic variability, and plume injection has
relatively small impact on the simulated surface BC concentrations in the
WUS. |
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