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

该EIS奖的两个主要研究目标是，通过应用综合分析方法，研究一个超过27年的中间层和低热层(MLT)区域内温度的合并卫星数据库，以发现可能的长期冷却趋势，并评估可能的太阳周期相关性。驱动长期变化的两个潜在过程：(1)动力强迫和(2)太阳直接强迫，将通过与最先进的全球环流模式--全大气社区气候模式(WACCM)所获得的结果进行比较来检验。将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的数据库。该奖项还将支持旨在通过使用WACCM比较和帮助诊断卫星数据中观察到的趋势和太阳周期变化，从理论上了解MLT区域的长期趋势和太阳周期变化的研究。由于MLT温度年代际变化可能是人为和太阳造成的，因此，所资助的研究将包括对可能引起趋势和太阳周期变化的来源进行全面的模拟分析，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相对于WACCM模型预测的变化的评估。这项研究中获得的研究结果预计将有助于就轨道寿命和潜在的碎片缓解战略作出政策决定。除了这些对社会的好处外，这一奖项还将支持HBCU机构的一名研究生的研究，以及介绍六名本科生(三年以上)参加研究活动。该奖项将支持首次全面研究MLT的长期温度趋势，该研究使用的是由不同平台上的四个卫星仪器进行的综合测量所建立的27年全球尺度数据记录。这一合并将伴随着一项验证分析，以检验这些独立数据库的合并是否成功。获奖研究目标的成就将大大促进对可能的人为温室气体增加以及太阳辐射变率和低层大气动力强迫所驱动的中层年代际变化的了解。这些结果将为更好地了解MLT区域的可变性和结构以及更好地预测未来中间层状态奠定基础。资助这项获奖研究的结果将清楚地表明，地球大气中二氧化碳(CO2)浓度的增加是否最终会导致电离层-热层-中间层(ITM)区域的全球大幅降温10至50K，使二氧化碳浓度比工业化前翻一番。这种冷却的影响远远超出了对地球上层大气的实质性改变。众所周知，MLT的显著冷却趋势表明轨道高度的热层密度相应减少，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学阻力，因此随着时间的推移，考虑到轨道资产的激增，特别是轨道碎片，碰撞的可能性更高。这一奖项反映了NSF的法定任务，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.