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Mineral dust and global tropospheric chemistry : Relative roles of photolysis and heterogeneous uptake
| Content Provider | Semantic Scholar |
|---|---|
| Author | Bian, Huisheng Zender, Charles S. |
| Copyright Year | 2003 |
| Abstract | We investigate the influence of mineral dust on tropospheric chemistry in the present climate at the global scale. The analysis examines the effects of dust on photochemistry and heterogeneous uptake, operating independently and together. In numerical experiments the size-resolved, time-varying mineral dust distribution predicted by the global Dust Entrainment And Deposition (DEAD) model perturbs the gas phase species in a global Chemical Transport Model (UCI CTM). We find that the photolysis perturbation dominates limited regions in the low to middle troposphere, while heterogeneous uptake dominates the rest of atmosphere (H2O2 is an exception). Coupling of the photochemical and heterogeneous effects of dust is weak in the global mean but significant in dusty regions, where coupling is sometimes responsible for more than 50% of local O3 changes. Ozone and odd-nitrogen concentrations are perturbed in opposite directions by photolysis and heterogeneous chemistry, resulting in a weak net change. However, both processes decrease the concentrations of OH and HO2. The global mean change due to dust is −0.7% for tropospheric O3, −11.1% for OH, −5.2% for HO2, and −3.5% for HNO3. Large seasonal signals are present near dust source regions. Over the north African region and tropical Atlantic Ocean downwind, OH decreases by −66.8%, a factor of six more than global mean value. In polar regions, O3 change is dominated by transported O3 and is not sensitive to local dust concentration. O3 change due to photochemistry is not only sensitive to dust vertical structure in dusty regions, but also depends on the availability of O3 precursors. O3 change due to heterogeneous reactions on dust is sensitive to dust vertical structure, mainly through the influence of temperature on uptake rates. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://dust.ess.uci.edu/ppr/ppr_BiZ03.pdf |
| Alternate Webpage(s) | http://dust.ess.uci.edu/ppr/ppr_BiZ03_csz.pdf |
| Alternate Webpage(s) | https://userpages.umbc.edu/~bian/main/papers/ppr_BiZ03.pdf |
| Alternate Webpage(s) | https://cloudfront.escholarship.org/dist/prd/content/qt3wp0p703/qt3wp0p703.pdf?t=mvk1x7 |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Brainwave entrainment Cefotiam Chemical transport model Chemical vapor deposition Ephrin Type-B Receptor 1, human Experiment Genetic Heterogeneity Greater Than Heme Oxygenase (Decyclizing) Hydrogen Peroxide Hydroxyl Radical Numerical analysis Ozone Photochemistry Yersinia enterocolitica O3 Ab:Titr:Pt:XXX:Qn photolysis |
| Content Type | Text |
| Resource Type | Article |
