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Excitation of the primary tropospheric chemical mode in a global three-dimensional model

Wild, O and Prather, M J (2000) Excitation of the primary tropospheric chemical mode in a global three-dimensional model. Journal of Geophysical Research: Atmospheres, 105 (D20). pp. 24647-24660. ISSN 0747-7309

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    Abstract

    Coupling of local chemical processes over the globe by atmospheric transport leads to the existence of chemical modes that are a fundamental characterization of global atmospheric chemistry and provide a true description of the atmospheric response to small changes in trace-gas emissions. Such coupled chemistry-transport modes in global tropospheric chemistry are an inherent feature of three-dimensional chemical transport models (CTMs). In CTMs these modes cannot be solved for explicitly, as they have been for the case of low-order, fully linearized systems, but they are investigated here through a series of perturbation experiments. When using meteorological fields that recycle every year, the long-lived modes are readily seen as seasonal decay patterns that e-fold each year. An important application of chemical modes is the study of how emissions of CO and NO excite perturbations to the CH4-like mode, the longest-lived (primary) mode found in tropospheric chemistry (i,e., with fixed stratospheric composition). Perturbation experiments are conducted with the University of California, Irvine, three-dimensional tropospheric CTM to identify this primary tropospheric mode and to determine its five-dimensional structure. The previous demonstrations of a long-lived chemical mode with 1.5 times the lifetime of CH4 are corroborated. The ability of emissions of CO and NO to excite this mode is then demonstrated, and a quantitative evaluation of the indirect effect of CO emissions on the greenhouse gases CH4 and tropospheric O-3 is made, showing that 100 kg of CO is equivalent to 5-6 kg of CH4 emissions.

    Item Type: Article
    Journal or Publication Title: Journal of Geophysical Research: Atmospheres
    Uncontrolled Keywords: OBSERVATORY PHOTOCHEMISTRY EXPERIMENT ; ORGANIC-COMPOUND EMISSIONS ; ATMOSPHERIC CHEMISTRY ; CARBON-MONOXIDE ; DIAGNOSTIC-TOOL ; ONLINE TRACERS ; TIME SCALES ; TRANSPORT ; OZONE ; O-3
    Subjects:
    Departments: Faculty of Science and Technology > Lancaster Environment Centre
    ID Code: 49592
    Deposited By: ep_importer_pure
    Deposited On: 07 Sep 2011 14:22
    Refereed?: Yes
    Published?: Published
    Last Modified: 17 Sep 2013 08:27
    Identification Number:
    URI: http://eprints.lancs.ac.uk/id/eprint/49592

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