The Michelson Interferometer for Global High‐resolution Thermospheric Imaging (MIGHTI) on NASA's Ionospheric Connection Explorer (ICON) mission is designed to measure the neutral wind and temperature between 90 and ∼300 km altitude. Using the Doppler Asymmetric Spatial Heterodyne (DASH) spectroscopy technique, observations from MIGHTI can be used to derive thermospheric winds by measuring Doppler shifts of the atomic oxygen red line (630.0 nm) and green line (557.7 nm). Harding et al. (2017, https://doi.org/10.1007/s11214‐017‐0359‐3) (Harding17) describe the wind retrieval algorithm in detail and point out the large uncertainties that result near the solar terminators and equatorial arcs, regions of large spatial gradients in airglow volume emission rates (VER). The uncertainties originate from the assumption of a constant VER at every given altitude, resulting in errors where the assumption is not valid when limb sounders, such as MIGHTI, observe regions with significant VER gradients. In this work, we introduce a new wind retrieval algorithm (Wu20) with the ability to account for VER that is asymmetric along the line of sight with respect to the tangent point. Using the predicted ICON orbit and simulated global VER variation, the greatest impact of the symmetric airglow assumption to the ICON vector wind product is found within 30° from the terminator when the spacecraft is in the dayside, causing an error of at least 10 m/s. The new algorithm developed in this study reduces the error near the terminator by a factor of 10. Although Wu20 improves the accuracy of the retrievals, it loses precision by 75% compared to Harding17.

中文翻译：

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星载，肢体测深多普勒干涉术中非对称发射率引起的误差：一种校正算法及其在ICON / MIGHTI中的应用

美国宇航局电离层连接探索器（ICON）任务的全球高分辨率热球成像（MIGHTI）迈克尔逊干涉仪旨在测量90至海拔300公里。使用多普勒非对称空间外差（DASH）光谱技术，通过测量原子氧红线（630.0 nm）和绿线（557.7 nm）的多普勒频移，可以将MIGHTI的观测结果用于推导出热圈风。哈丁等。（2017，https://doi.org/10.1007/s11214‐017‐0359‐3）（Harding17）详细描述了风的取回算法，并指出了在太阳终结器和赤道弧附近，大区域附近产生的巨大不确定性气辉体积发射率（VER）的空间梯度。不确定性源自在每个给定高度上均具有恒定VER的假设，导致当肢体测深仪（例如MIGHTI）观察到具有明显VER梯度的区域时该假设无效的错误。在这项工作中 我们介绍了一种新的风速取回算法（Wu20），该算法可以计算VER，该VER相对于切点沿视线是不对称的。使用预测的ICON轨道和模拟的全球VER变化，当航天器在白天时，对称气辉假设对ICON矢量风积的最大影响是在距终结者30°范围内，造成至少10 m / s。在这项研究中开发的新算法将终止符附近的错误降低了10倍。尽管Wu20提高了检索的准确性，但与Harding17相比，它的准确性降低了75％。当航天器在白天时，对称气辉假设对ICON矢量风积的最大影响是在距终结器30°范围内，造成至少10 m / s的误差。在这项研究中开发的新算法将终止符附近的错误降低了10倍。尽管Wu20提高了检索的准确性，但与Harding17相比，它的准确性降低了75％。当航天器在白天时，对称气辉假设对ICON矢量风积的最大影响是在距终结器30°范围内，造成至少10 m / s的误差。在这项研究中开发的新算法将终止符附近的错误降低了10倍。尽管Wu20提高了检索的准确性，但与Harding17相比，它的准确性降低了75％。