HBCU-Excellence in Research: Long-term Trends in Data from Hampton University (HU)-led Satellite Experiments

该环境影响报告书的两个主要研究目标是通过应用综合分析方法研究27年来中间层和低热层区域内温度的合并卫星数据库，以探测可能的长期冷却趋势，并评估可能的太阳周期依赖性。 驱动长期变率的两个潜在过程：（1）动力强迫和（2）直接太阳强迫，将通过与使用最先进的全球环流模式-全大气社区气候模式（WACCM）获得的结果进行比较来检查。用于这项研究的卫星数据包括来自HALOE、SABER、MLS和SOFIE的MLT温度观测数据，这些数据将被合并以生成扩展数据库。该奖项还将包括支持旨在实现对MLT区域长期趋势和太阳周期变化的理论理解的研究，方法是利用WACCM与卫星数据中观察到的趋势和太阳周期变化进行比较并帮助诊断。由于MLT温度十年变化的可能人为和太阳起源，资助的研究将包括对趋势和太阳周期变化可能起源的来源进行全面的建模分析，例如，臭氧化学、辐射冷却和低层大气波强迫以及相关的MLT动力学。这项研究将有助于加强对高层大气变化相对于WACCM模型预测的评估。预计这项研究的结果将有助于就轨道寿命和可能的碎片缓减战略作出知情的政策决定。除了这些对社会的好处，该奖项还将支持在HBCU机构的研究生的研究，以及介绍六个本科生（三年以上）的研究活动。该奖项将支持首次对MLT长期温度趋势进行全面研究，该研究使用27年的全球尺度数据记录，该数据记录是由不同平台上的四个卫星仪器进行的综合测量构建的。在合并的同时，将进行验证分析，以检验这些单独的数据库合并是否成功。该奖项研究目标的实现将大大增进对可能的人为温室气体增加以及太阳辐照度变异和低层大气动力强迫所驱动的中间层十年变化的认识。这些结果将形成一个基础，支持更好地了解MLT区域的变化和结构，并更好地预测未来中间层状态的能力。资助这项研究的结果将提供明确的二氧化碳（CO2）在地球大气层中的浓度增加是否最终会导致电离层-热层-中间层（ITM）区域的大幅全球冷却10至50 K，使CO2浓度从工业化前时代增加一倍。这种冷却的影响远远超出了地球高层大气的实质性改变。 已知一个显著的MLT冷却趋势表明轨道高度的热层密度相应降低，减少了从国际空间站到轨道碎片的所有轨道资产的空气动力阻力，从而导致随着时间的推移发生碰撞的可能性增加，考虑到轨道资产特别是轨道碎片的扩散，该奖项反映了NSF的法定使命，并通过使用基金会的学术价值和更广泛的影响审查标准。

The two major research objectives of this EIS award are to study through the application of comprehensive analysis approaches a merged satellite data base of temperatures within the mesosphere and lower thermosphere (MLT)region extending over 27 years to detect possible long-term cooling trends and also to assess possible solar cycle dependence. Two potential processes driving the long-term variability: (1) dynamical forcing and (2) direct solar forcing, would be examined by comparisons with results obtained using a state-of-the-art general global circulation model - the Whole Atmosphere Community Climate Model(WACCM. The satellite data to be used for this study includes MLT temperature observations from HALOE, SABER, MLS and SOFIE that would be merged to generate the extended database. The award would also include support of research aimed at achieving a theoretical understanding of long-term trends and solar cycle variations in the MLT region by using WACCM to compare with and to help diagnose the observed trends and solar cycle variations in the satellite data. Because of the possible anthropogenic and solar origin of the decadal changes in the MLT temperatures, the funded research would include a comprehensive modeling analysis of sources from which trends and solar cycle variations might originate, e.g., ozone chemistry, radiative cooling and lower atmosphere wave forcing and related MLT dynamics. This research would help enhance the assessment of changes in the upper atmosphere relative to the WACCM model predictions. The findings obtained in this research are expected to help inform policy decisions on orbital lifetimes and potential debris mitigation strategies. In addition to these benefits to society, this award would also support the research of a graduate student at a HBCU institution as well as introducing six undergraduates (over three years) to research activities. This award would support the first comprehensive study of long-term MLT temperature trends using a 27-year global scale data record constructed from the combined measurements made by four satellite instruments on different platforms. This merger would be accompanied with a validation analysis that would test the success of the merger of these separate databases. The achievements of the award research objectives would significantly advance knowledge of mesosphere decadal changes driven by possible anthropogenic greenhouse gas increases as well as solar irradiance variability and lower atmosphere dynamical forcing. These results would form a base supporting the development of a much better understanding of the variability and structure of the MLT region and a better capability to predict the future mesosphere state. The outcome of funding this award research would provide clarity as to whether the increasing concentration of carbon dioxide (CO2) within the Earth's atmosphere would eventually lead to a substantial global cooling of the ionosphere-thermosphere-mesosphere (ITM) region by 10 to 50 K for doubled CO2 concentrations from pre-industrial times. The implications of this cooling go far beyond the substantial modification of the Earth's upper atmosphere. A significant MLT cooling trend is known to indicate corresponding thermosphere density decrease at orbital altitudes, reducing aerodynamic drag on all orbiting assets, from the International Space Station to orbital debris, and thus leads to higher probabilities of collisions over time, given the proliferation of orbital assets and especially orbital debris.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.