We evaluated a method for retrieving vertical temperature and Doppler wind velocity profiles of the Venusian nightside mesosphere from the CO2 absorption line resolved by mid-infrared heterodyne spectroscopy. The achievable sensitive altitude and retrieval accuracy were derived with multiple model spectra generated from various temperature and wind velocity profiles with several noise levels. The temperature profiles were retrieved at altitudes of 70–100 km with a vertical resolution of 5 km and a retrieval accuracy of ± 15 K. The wind velocity was also retrieved at an altitude of approximately 85 km with a vertical resolution of 10 km and a retrieval accuracy of ± 25–50 m/s. In addition, we studied an event and applied our method to spectra obtained by the HIPWAC instrument attached to the NASA/IRTF 3-m telescope on May 19–22, 2012. Retrieved wind velocities in a latitude of 33° S at 3:00 LT were interpreted as subsolar-to-antisolar (SS-AS) flows at altitudes of 84 ± 6 km and 94 ± 7 km, and they were stronger than expected. This result suggested that the transition between the retrograde superrotational zonal (RSZ) wind and SS-AS flow may occur at altitudes below 90 km which previously was predicted to be the transition region. This work provides a basis for our analysis of further observations obtained by a mid-infrared heterodyne spectrometer MILAHI attached to the Tohoku University 60-cm telescope at Haleakalā, Hawaii.

中文翻译：

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一种从外差光谱观测到的中红外 CO2 吸收线中反演金星夜间中间层温度和风速剖面的方法的评价

我们评估了一种从中红外外差光谱法解析的 CO2 吸收线中检索金星夜间中间层的垂直温度和多普勒风速剖面的方法。可实现的敏感高度和反演精度是通过多个模型频谱推导出来的，这些频谱是从具有多个噪声级别的各种温度和风速剖面生成的。温度剖面在 70-100 公里的高度反演，垂直分辨率为 5 公里，反演精度为 ± 15 K。风速也在约 85 公里的高度反演，垂直分辨率为 10 公里， ± 25–50 m/s 的检索精度。此外，我们研究了一个事件，并将我们的方法应用于 2012 年 5 月 19 日至 22 日连接到 NASA/IRTF 3 米望远镜的 HIPWAC 仪器获得的光谱。在 3:00 LT 的 33° S 纬度处检索到的风速被解释为 84 ± 6 公里和 94 ± 7 公里高度的亚太阳到反太阳 (SS-AS) 气流，它们比预期的要强。这一结果表明，逆行超旋转纬向 (RSZ) 风和 SS-AS 流之间的过渡可能发生在 90 公里以下的高度，而这之前被预测为过渡区。这项工作为我们分析由附属于夏威夷哈雷阿卡拉的东北大学 60 厘米望远镜的中红外外差光谱仪 MILAHI 获得的进一步观测提供了基础。这一结果表明，逆行超旋转纬向 (RSZ) 风和 SS-AS 流之间的过渡可能发生在 90 公里以下的高度，而这之前被预测为过渡区。这项工作为我们分析由附属于夏威夷哈雷阿卡拉的东北大学 60 厘米望远镜的中红外外差光谱仪 MILAHI 获得的进一步观测提供了基础。这一结果表明，逆行超旋转纬向 (RSZ) 风和 SS-AS 流之间的过渡可能发生在 90 公里以下的高度，而这之前被预测为过渡区。这项工作为我们分析由附属于夏威夷哈雷阿卡拉的东北大学 60 厘米望远镜的中红外外差光谱仪 MILAHI 获得的进一步观测提供了基础。