The atmospheric CH4 increase since the Last Glacial Maximum: (2) Interactions with oxidants ...
Two studies of the effect of changing CH4 fluxes on global tropospheric oxidant levels, O3, OH, H2O2, have been performed with a multi-box photochemical model. (1) A sensitivity study is made by scaling back CH4, CO and NO emissions relative to present-day budgets. When the CH4 ice core record is co...
| Main Authors: | , , , |
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| Format: | Text |
| Language: | English |
| Published: |
Stockholm University Press
1993
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| Subjects: | |
| Online Access: | https://dx.doi.org/10.13016/m2kvnr-lnqr https://mdsoar.org/handle/11603/35043 |
| Summary: | Two studies of the effect of changing CH4 fluxes on global tropospheric oxidant levels, O3, OH, H2O2, have been performed with a multi-box photochemical model. (1) A sensitivity study is made by scaling back CH4, CO and NO emissions relative to present-day budgets. When the CH4 ice core record is compared to calculated CH4 abundances, corresponding CH4 fluxes for the pre-industrial Holocene (PIH) and Last Glacial Maximum (LGM) are fairly well-constrained: 175–225 Tg CH4/yr for PIH and 100–130 Tg CH4/yr for LGM. Except for OH at fluxes of 100–200 Tg CH4/yr, preindustrial oxidant concentrations levels are not narrowly defined by the CH4 record. The small range of CH4 flux and OH abundance at the LGM is due to strong CH4–OH feedbacks. (2) Specific scenarios for CH4/CO/NO are selected to represent sources for the PIH and LGM. The CH4 budget is taken from an evaluation of wetlands and other natural sources. For CO and NO, apparent O3 levels and ice-core-derived H2O2 for the PIH are used to constrain PIH CO and NO ... |
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