EAGER: A New Look at the Middle Atmosphere through the Eyes of SABER (Sounding of the Atmosphere using Broadband Emission Radiometry)

研究人员将研究中间层和低热层（MLT）中的各种红外（IR）发射机制，这可能是在90公里处出现无法解释的增强IR特征的原因。使用宽带发射辐射测量法探测大气层是美国航天局热层、电离层、中间层、能量学和动力学（TIMED）使命上的四个仪器之一，是一个10通道宽带边缘扫描红外辐射计，覆盖1.27至17微米的光谱范围。SABER已经提供了十年来有关动力学温度、压力、臭氧、二氧化碳、水蒸气和原子氧的信息。这些结果的解释，这是强烈影响的MLT中的红外辐射的模型的质量，理解这一地区的物理和化学具有至关重要的意义。自SABER的4.3微米通道中的卫星操作开始以来，就存在类似于层状增强的红外临边发射特征。这一特征局限于与85-95公里切线高度相对应的高度区域，并具有明显的空间和时间变化性。尽管增强的临边辐射在所有纬度和季节都存在，但它们在极地夏季MLT似乎更强。对其他航天器观测结果的初步分析揭示了类似的特征，尽管这些仪器的操作方式大不相同，这表明这至少部分是一种真实的现象。我们目前的红外发射模型在MLT中没有预测到这种增强，特别是与在其他通道中观察到的类似效应相比。由于对其起源缺乏了解，十年来这种效应一直被忽视，因此，高层大气科学界和空间科学界一般都不了解这种效应。研究人员将研究一些完全不同的跨学科方法，其中包括MLT的分子，原子和离子化合物的非平衡化学及其与尘埃和冰粒的可能相互作用，从光解和化学反应产物到分子振动的能量转移的各种潜在机制，非LTE分子发射，吸收，辐射在不同光谱区域的变换和多重散射等 调查将解决一个功能，可能会改变在MLT的CO2特性的理解。因此，这些结果可能对大气化学和气候产生重大影响。此外，这项研究将提供一个更强大的红外辐射分析，可以在以后扩展到其他空间任务。

The investigators will study various Infrared (IR) emission mechanisms in the Mesosphere and Lower Thermosphere (MLT), which may be responsible for a largely unexplained enhanced IR feature at ~90 km. The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER), one of four instruments on board of NASA's Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) mission, is a 10-channel broadband limb-scanning infrared radiometer covering the spectral range from 1.27 to 17 microns. SABER has already provided a decade worth of information about kinetic temperature, pressure, ozone, carbon dioxide, water vapor and atomic oxygen. The interpretation of these results, which are strongly affected by the quality of models of the IR emissions in the MLT, have crucial importance for understanding the physics and chemistry of this region. An IR limb emission feature that resembles a layer-like enhancement has been present since the beginnings of the satellite operations in SABER's 4.3 micron channel. This feature is localized at an altitude region that corresponds to tangent heights between 85-95 km and has a distinct spatial and temporal variability. Although the enhanced limb radiances are present at all latitudes and seasons, they appear to be stronger at the polar summer MLT. Preliminary analysis of observations from other spacecraft reveal similar features although those instruments operate significantly different, which indicate this is, at least in part, a real phenomena. This enhancement is not predicted by our current IR emission models in the MLT, in particular when compared to similar effects observed in additional channels. Due to a lack of understanding of its origins, this effect has been ignored for a decade and, as a result, is generally unknown by the aeronomy and space science communities. The investigators will study a number of radically different as well as interdisciplinary approaches, among them non-equilibrium chemistry of molecular, atomic and ionic compounds of MLT and their possible interactions with dust and ice particles, various potential mechanism of energy transfer from photolysis and chemical reaction products to molecular vibrations, non-LTE molecular emission, absorption, transformation and multiple scattering of radiation in various spectral regions, etc The investigation will address a feature that may alter the understanding of the CO2 characteristics in the MLT. As such, the results may have high impact on atmospheric chemistry and climate. Additionally, this study will provide a more robust analysis of IR radiances that can be later expanded to other space missions.