Search for hydrogen peroxide in the Martian atmosphere by the Planetary Fourier Spectrometer onboard Mars Express,
Search for hydrogen peroxide in the Martian atmosphere by the Planetary Fourier Spectrometer onboard Mars Express,
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通过火星快车上的行星傅立叶光谱仪搜索火星大气中的过氧化氢，
DOI：
10.1016/j.icarus.2014.09.034
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发表时间：
2015
期刊：
影响因子：
3.2
通讯作者：
and V. Formisano
中科院分区：
文献类型：
--
作者：
Aoki;S.;M. Giuranna;Y. Kasaba;H. Nakagawa;G. Sindoni;A. Geminale;and V. Formisano
我们使用火星快车上的行星傅里叶光谱仪(PFS)在火星五年(MY27-31)测量的数据来搜索火星大气中的过氧化氢(H_2O_2)。众所周知，过氧化氢在火星大气的氧化能力中起着关键作用。然而，在文献中只能找到一些基于地面观测的研究。在这里，我们使用航天器上的仪器进行了长期测量，首次对过氧化氢进行了分析。我们使用了过氧化氢的ν4波段，光谱范围在359cm−1到382cm−1之间，其中过氧化氢的强特征出现在362cm−1和379cm−1附近。由于即使在强波段预计这些特征也会非常弱，因此进行了敏感的数据校准，并选择了大量的光谱并进行了平均。我们在相对较低的纬度(50°S-50°N)做了三个不同季节的平均光谱。我们在379cm−1处发现了过氧化氢的特征，而在362cm−1处由于数据中的大量不确定性而没有检测到明显的特征。由此得到的H_2O_2混合比接近检测下限：16℃±9.19℃ATLS=0.20-120°，35℃±9.32℃~240℃，41℃±9.28℃~360°。反演值仅显示了第三个季节的H_2O_2的检测结果，其他时间段的值提供了上限。PFS得出的这些长期平均丰度与地面观测报告的结果基本一致。根据我们推导出的H_2O_2的混合比，在最短的情况下，火星大气中的甲烷的寿命估计为几十年。我们的结果和对CH4的零星检测表明，存在不受大气氧化影响的强大CH4汇。
We searched for hydrogen peroxide (H2O2) in the Martian atmosphere using data measured by the Planetary Fourier Spectrometer (PFS) onboard Mars Express during five martian years (MY27–31). It is well known that H2O2plays a key role in the oxidizing capacity of the Martian atmosphere. However, only a few studies based on ground-based observations can be found in the literature. Here, we performed the first analysis of H2O2using long-term measurements by a spacecraft-borne instrument. We used the ν4band of H2O2in the spectral range between 359 cm−1and 382 cm−1where strong features of H2O2are present around 362 cm−1and 379 cm−1. Since the features were expected to be very weak even at the strong band, sensitive data calibrations were performed and a large number of spectra were selected and averaged. We made three averaged spectra for different seasons over relatively low latitudes (50°S–50°N). We found features of H2O2at 379 cm−1, whereas no clear features were detected at 362 cm−1due to large amounts of uncertainty in the data. The derived mixing ratios of H2O2were close to the detection limits: 16 ± 19 ppb atLs= 0–120°, 35 ± 32 ppb atLs= 120–240°, and 41 ± 28 ppb atLs= 240–360°. The retrieved value showed the detection of H2O2only for the third seasonal period, and the values in the other periods provided the upper limits. These long-term averaged abundances derived by the PFS generally agreed with the ones reported by ground-based observations. From our derived mixing ratio of H2O2, the lifetime of CH4in the Martian atmosphere is estimated to be several decades in the shortest case. Our results and sporadic detections of CH4suggest the presence of strong CH4sinks not subject to atmospheric oxidation.