Photochemistry and diffusion in Jupiter's stratosphere: Constraints from ISO observations and comparisons with other giant planets
Photochemistry and diffusion in Jupiter's stratosphere: Constraints from ISO observations and comparisons with other giant planets
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木星平流层中的光化学和扩散：ISO 观测的限制以及与其他巨行星的比较
DOI：
10.1029/2005je002411
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发表时间：
2005
影响因子：
--
通讯作者：
H. Feuchtgruber
中科院分区：
文献类型：
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作者：
J. Moses;T. Fouchet;B. Bézard;G. Gladstone;E. Lellouch;H. Feuchtgruber
[1]我们已经开发了一个一维的，日平均的，光化学模型的木星的平流层，耦合光解，化学动力学，垂直扩散和辐射传输。将有关碳氢化合物丰度和垂直分布的预测与红外空间天文台（ISO）的观测结果进行比较，以更好地约束大气成分，更好地定义涡流扩散系数分布，并更好地了解产生和破坏的化学反应方案观察到的成分。通过模型数据的比较，我们确定了木星上C2H6的摩尔分数在3.5 mbar时为（4.0 ± 1.0）× 10− 6，在7 mbar时为（2.7 ± 0.7）× 10−6，C2H2的摩尔分数在0.25 mbar时为（1.4 ± 0.8）× 10−6，在2 mbar时为（1.5 ± 0.4）× 10−7。在30 mbar以上，CH3C2H和C6H6的柱密度分别为（1.5 ± 0.4）× 1015 cm−2和（8.0 ± 2）× 1014 cm−2。使用相同的反应列表，我们还开发了土星，天王星和海王星的光化学模型。虽然模型提供了很好的一阶预测的碳氢化合物丰度的巨行星，我们目前的化学反应方案不重现C2Hx碳氢化合物的相对丰度。像C2H4和C2H2这样的不饱和碳氢化合物在木星上转化为像C2H6这样的饱和碳氢化合物的效率比在其他巨行星上更高，比模型预测的更有效。在我们的理解在低温和低压下的氢为主的大气中的光化学的进一步进展取决于高质量的动力学数据的采集。
[1] We have developed a one-dimensional, diurnally averaged, photochemical model for Jupiter's stratosphere that couples photodissociation, chemical kinetics, vertical diffusion, and radiative transport. The predictions regarding the abundances and vertical profiles of hydrocarbon compounds are compared with observations from the Infrared Space Observatory (ISO) to better constrain the atmospheric composition, to better define the eddy diffusion coefficient profile, and to better understand the chemical reaction schemes that produce and destroy the observed constituents. From model-data comparisons we determine that the C2H6 mole fraction on Jupiter is (4.0 ± 1.0) × 10−6 at 3.5 mbar and (2.7 ± 0.7) × 10−6 at 7 mbar, and the C2H2 mole fraction is (1.4 ± 0.8) × 10−6 at 0.25 mbar and (1.5 ± 0.4) × 10−7 at 2 mbar. The column densities of CH3C2H and C6H6 are (1.5 ± 0.4) × 1015 cm−2 and (8.0 ± 2) × 1014 cm−2, respectively, above 30 mbar. Using identical reaction lists, we also have developed photochemical models for Saturn, Uranus, and Neptune. Although the models provide good first-order predictions of hydrocarbon abundances on the giant planets, our current chemical reaction schemes do not reproduce the relative abundances of C2Hx hydrocarbons. Unsaturated hydrocarbons like C2H4 and C2H2 appear to be converted to saturated hydrocarbons like C2H6 more effectively on Jupiter than on the other giant planets, more effectively than is predicted by the models. Further progress in our understanding of photochemistry at low temperatures and low pressures in hydrogen-dominated atmospheres hinges on the acquisition of high-quality kinetics data.