A latitudinal survey of CO, OCS, H2O, and SO2 in the lower atmosphere of Venus: Spectroscopic studies using VIRTIS‐H
A latitudinal survey of CO, OCS, H2O, and SO2 in the lower atmosphere of Venus: Spectroscopic studies using VIRTIS‐H
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金星低层大气中 CO、OCS、H2O 和 SO2 的纬度调查：使用 VIRTIS-H 进行光谱研究
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发表时间：
2008
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通讯作者：
F. Henry
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作者：
E. Marcq;B. Bézard;P. Drossart;G. Piccioni;J. Réess;F. Henry
[1]金星快车上的可见光和红外热成像光谱仪（VIRTIS-H）的高分辨率通道（R 2000）在2.3 μm窗口提供了大量的夜侧红外热发射光谱。因此，在航天器可以到达但从地球上无法观测到的较高纬度上，利用这一光谱窗口可以推断出30-40公里范围内各种次要物种的混合比率。证实了先前已知的一氧化碳（CO）向高纬度的增强，并扩展到60°，在36公里处混合比从24 ± 3到31 ± 2 ppmv。羰基硫（OCS）的测量结果也与先前怀疑的纬度变化一致，这些变化与CO的变化相关，在33公里处范围在2.5 ± 1和4 ± 1 ppmv之间。还推导出了探测高度范围内水蒸气（H2O，31 ± 2 ppmv）和二氧化硫（SO2，130 ± 50 ppmv）平均丰度的新限制。CO和OCS的变化被解释为大规模的垂直运动，根据目前的测试，各种化学和动力学模型的解释。在这种情况下，这些变化可能有助于限制对流层低层中这些物种的化学时间尺度。
[1] The high-resolution channel (R ≃ 2000) of the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) instrument (VIRTIS-H) aboard Venus Express has provided numerous spectra of the nightside infrared thermal emission in the 2.3-μm window. Mixing ratios of various minor species in the 30–40 km range could therefore be inferred using this spectral window at higher latitudes accessible to the spacecraft but which cannot be observed from Earth. The previously known enhancement in carbon monoxide (CO) toward high latitudes is confirmed and extended up to 60° with a mixing ratio varying from 24 ± 3 to 31 ± 2 ppmv at 36 km. Measurements of carbonyl sulfide (OCS) also agree with the previously suspected latitudinal variations that are anticorrelated with those of CO, ranging between 2.5 ± 1 and 4 ± 1 ppmv at 33 km. New constraints were also derived on the mean abundance of water vapor (H2O, 31 ± 2 ppmv) and sulfur dioxide (SO2, 130 ± 50 ppmv) in the probed altitude range. CO and OCS variations are interpreted as caused by large-scale vertical motions, an explanation under current testing by various chemical and dynamical modeling. In such a case, these variations may help constrain the chemical time scale of those species in the lower troposphere.