 |
| Titel |
Quantifying the uncertainty in simulating global tropospheric composition due to the variability in global emission estimates of Biogenic Volatile Organic Compounds |
| VerfasserIn |
J. E. Williams, P. F. J. Velthoven, C. A. M. Brenninkmeijer |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 5 ; Nr. 13, no. 5 (2013-03-11), S.2857-2891 |
| Datensatznummer |
250018487
|
| Publikation (Nr.) |
 copernicus.org/acp-13-2857-2013.pdf |
|
|
|
|
|
| Zusammenfassung |
| The emission of organic compounds from biogenic processes acts as an
important source of trace gases in remote regions away from urban
conurbations, and is likely to become more important in future decades due
to the further mitigation of anthropogenic emissions that affect air quality
and climate forcing. In this study we examine the contribution of biogenic
volatile organic compounds (BVOCs) towards global tropospheric composition
using the global 3-D chemistry transport model TM5 and the recently developed
modified CB05 chemical mechanism. By comparing regional BVOC emission
estimates we show that biogenic processes act as dominant sources for many
regions and exhibit a large variability in the annually and seasonally
integrated emission fluxes. By performing sensitivity studies we find that
the contribution of BVOC species containing between 1 to 3 carbon atoms has
an impact on the resident mixing ratios of tropospheric O3 and CO,
accounting for ~2.5% and ~10.8% of the simulated global
distribution, respectively. This is approximately a third
of the cumulative effect introduced by isoprene and the monoterpenes. By
examining an ensemble of 3-D global chemistry transport simulations which
adopt different global BVOC emission inventories we determine the associated
uncertainty introduced towards simulating the composition of the troposphere
for the year 2000. By comparing the model ensemble values against a
composite of atmospheric measurements we show that the effects on
tropospheric O3 are limited to the lower troposphere (with an
uncertainty between −2% to 10%), whereas that for tropospheric CO
extends up to the upper troposphere (with an uncertainty of between 10 to
45%). Comparing the mixing ratios for low molecular weight alkenes in TM5
against surface measurements taken in Europe implies that the cumulative
emission estimates are too low, regardless of the chosen BVOC inventory.
This variability in the global distribution of CO due to BVOC emissions
introduces an associated uncertainty in the tropospheric CO burden of
11.4%, which impacts strongly on the oxidative capacity of the
troposphere, introducing an uncertainty in the atmospheric lifetime of the
greenhouse gas CH4 of ~3.3%. This study thus
identifies the necessity of placing further constraints on non-CH4
global biogenic emission estimates in large-scale global atmospheric
chemistry models. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|