EAGER: What is the Cause of Strong Carbon Dioxide 15 Micron Emission in the Mesosphere and Lower Thermosphere? Resolving the Puzzle

EAGER：中层和低热层强烈二氧化碳 15 微米排放的原因是什么？

• 批准号: 2125760
• 负责人: Alexander Kutepov
• 金额: $ 12.28万
• 依托单位: Catholic University of America
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2125760&HistoricalAwards=false
• 关键词: EAGER; What; Cause; Strong; Carbon

This award supports a 2-year investigation into various infrared (IR) emission mechanisms in the Mesosphere and Lower Thermosphere (MLT) region that may be responsible for largely unexplained enhanced IR emission in the CO2 15-μm band above ~90 km. This 15-μm emission is the main cooling mechanism of MLTs of Earth, Venus and Mars. This IR emission is also used to retrieve MLT temperatures by a number of satellite instruments such as SABER/TIMED, MIPAS/ENVUSAT-1, CRISTA/ASTRO-SPAS, and others. In the MLT region the formation of this radiation is dominated by excitation of CO2 molecules by inelastic collisions with the O(3P) atoms and subsequent emission of the 15-μm quanta. However, this process remains still poorly understood despite many studies over the past several decades. Laboratory measurements at different laboratories applying various techniques have found low values of the CO2+O(3P) reaction rate coefficient. The use of this low rate in the model calculations does not result in the CO2(ν2) excitation needed to reproduce the strong CO2 15-μm emission observed. In order to fit these observations, the laboratory rate must be increased by a factor of 4. This award is aimed at a search for one or more significant mechanisms of the CO2 excitation that is not accounted for in the current non-local thermodynamic equilibrium (non-LTE) models of the MLT IR emissions. This award would feature the inclusion of a number of radically different and complex processes of energy transfer to molecular vibrational and rotational states which may be excited in the MLT region. The new investigation is expected to lead to a more accurate understanding of how this 15-μm IR emission serve as the main IR cooling pathway for the MLT region. The new results would potentially have high impact on the modeling of atmospheric dynamics, chemistry and climate for the MLT region. Additionally, this study will provide a more robust analysis of IR radiances that can be later expanded to other space missions, including those designed to observe Mars, Venus and terrestrial exo-planets. The award would also examine whether there is a need for significant alteration of the calculations of the IR radiative cooling/heating of MLT in GCMs.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该奖项支持对中层和较低热层（MLT）区域中各种红外（IR）排放机制进行的2年投资，这可能导致在大约90 km高于90 km的15μm频带中大部分意外增强的IR发射。这种15μm的发射是地球，金星和火星MLT的主要冷却机制。该IR发射还用于通过许多卫星仪器（例如Saber/Timeed，Mipas/Envusat-1，Crista/asto-Spas等）来检索MLT温度。在MLT区域中，通过与O（3p）原子的无弹性碰撞以及随后的15μm量化的发射，这种辐射的形成是由二氧化碳分子兴奋的主导。但是，在过去的几十年中，这一过程仍然对许多研究仍然了解不足。应用各种技术的不同实验室的实验室测量发现CO2+O（3p）反应速率的低值关键。模型计算中这种低率的使用并不会导致观察到的强CO2 15-μm发射所需的二氧化碳（ν2）兴奋。为了适应这些观察结果，必须提高实验室速率4。该奖项旨在寻找一种或多种重要的二氧化碳兴奋机制，这些机制在当前的非本地热力学平衡（非L-LTE）模型中尚未考虑到MLT IR发射。该奖项将包括许多根本不同的和复杂的能量转移过程，这些过程可能会在MLT区域激发分子振动和旋转状态。预计新的研究将使人们更准确地了解这种15μm的IR发射是MLT区域的主要IR冷却途径。新结果可能会对MLT区域的大气动力学，化学和气候的建模产生很大的影响。此外，这项研究将提供对IR辐射的更强大的分析，以后可以将其扩展到其他空间任务，包括旨在观察火星，金星和陆地外的外观行星的任务。该奖项还将研究是否需要重大改变GCM中MLT的IR辐射冷却/加热的计算。该奖项反映了NSF的法定任务，并通过使用基金会的智力优点和更广泛的影响来评估NSF的法定任务，并被认为是珍贵的支持。