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| Titel |
Synergistic Study of Hydrocarbon Photochemistry in the Laboratory and Planetary Atmospheres |
| VerfasserIn |
M. C. Liang, D. Henze, M. Adamkovics, E. F. Chu, K. Boering, Y. L. Yung |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250026324
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| Zusammenfassung |
| A synergistic study of hydrocarbon photochemistry in the laboratory and planetary
atmospheres has been carried out using the Caltech/JPL KINETICS photochemical model
and laboratory measurements from Adamkovics and Boering (2003). The laboratory
simulations provide the data for the time-evolution of gaseous species such as H2, C2H2,
C2H4, C2H6, C3H4, C4H2 and C4H10 during UV irradiation of CH4. We apply forward and
adjoint models to analyze the experiments. Different photochemical schemes (e.g., Moses et
al. 2000, 2005) are compared and modified to reproduce the laboratory results. We first test
the full sensitivity of the model results to all chemical kinetics using the adjoint model and
show that the abundances of C2H2, C2H4, C2H6, and C4H10 can be well reproduced
while that of C4H2 is underestimated by 1-2 orders of magnitude. The abundance of
C3H4 is underestimated with Moses et al. (2000) kinetics but overestimated with
Moses et al. (2005) kinetics. This suggests a major gap in our understanding of
chemical pathways to higher hydrocarbons. We next examine higher order hydrocarbon
chemistry (>C2). In this case, we assume that all rate coefficients for the chemistry
of C1 and C2 hydrocarbons remain invariant in the adjoint optimization. Better
agreement is achieved, but complete agreement remains elusive. Further laboratory
measurements are urgently needed to constrain the pathways. The implications for
modeling the atmospheres of Titan and the giant planets (e.g., Jupiter) are discussed. |
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