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| Titel |
Kinetic model framework for aerosol and cloud surface chemistry and gas-particle interactions – Part 1: General equations, parameters, and terminology |
| VerfasserIn |
U. Pöschl, Y. Rudich, M. Ammann |
| 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 ; 7, no. 23 ; Nr. 7, no. 23 (2007-12-10), S.5989-6023 |
| Datensatznummer |
250005271
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| Publikation (Nr.) |
 copernicus.org/acp-7-5989-2007.pdf |
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| Zusammenfassung |
Aerosols and clouds play central roles in atmospheric chemistry and physics,
climate, air pollution, and public health. The mechanistic understanding and
predictability of aerosol and cloud properties, interactions,
transformations, and effects are, however, still very limited. This is due
not only to the limited availability of measurement data, but also to the
limited applicability and compatibility of model formalisms used for the
analysis, interpretation, and description of heterogeneous and multiphase
processes. To support the investigation and elucidation of atmospheric
aerosol and cloud surface chemistry and gas-particle interactions, we
present a comprehensive kinetic model framework with consistent and
unambiguous terminology and universally applicable rate equations and
parameters. It enables a detailed description of mass transport and chemical reactions at
the gas-particle interface, and it allows linking aerosol and cloud surface processes
with gas phase and particle bulk processes in systems with multiple chemical
components and competing physicochemical processes.
The key elements and essential aspects of the presented framework are: a
simple and descriptive double-layer surface model (sorption layer and
quasi-static layer); straightforward flux-based mass balance and rate
equations; clear separation of mass transport and chemical reactions;
well-defined and consistent rate parameters (uptake and accommodation coefficients,
reaction and transport rate coefficients); clear distinction between gas
phase, gas-surface, and surface-bulk transport (gas phase diffusion, surface and bulk accommodation); clear distinction between
gas-surface, surface layer, and surface-bulk reactions (Langmuir-Hinshelwood
and Eley-Rideal mechanisms); mechanistic description of concentration and
time dependences (transient and steady-state conditions); flexible addition of unlimited numbers of chemical species and
physicochemical processes; optional aggregation or resolution of intermediate
species, sequential processes, and surface layers; and full compatibility with traditional resistor model formulations.
The outlined double-layer surface concept and formalisms represent a minimum
of model complexity required for a consistent description of the non-linear
concentration and time dependences observed in experimental studies of
atmospheric multiphase processes (competitive co-adsorption and surface
saturation effects, etc.). Exemplary practical applications and model
calculations illustrating the relevance of the above aspects are presented in
a companion paper (Ammann and Pöschl, 2007).
We expect that the presented model framework will serve as a useful tool and
basis for experimental and theoretical studies investigating and describing
atmospheric aerosol and cloud surface chemistry and gas-particle
interactions. It shall help to end the "Babylonian confusion" that seems to
inhibit scientific progress in the understanding of heterogeneous chemical
reactions and other multiphase processes in aerosols and clouds. In
particular, it shall support the planning and design of laboratory
experiments for the elucidation and determination of fundamental kinetic
parameters; the establishment, evaluation, and quality assurance of
comprehensive and self-consistent collections of rate parameters; and the
development of detailed master mechanisms for process models and derivation
of simplified but yet realistic parameterizations for atmospheric and climate
models. |
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