CEDAR: Atmospheric Coupling via Energetic Electron Precipitation (EEP)

该奖项将研究北极内部产生的活性氮（NOx）从中间层和低层热层（MLT）向下输送。该奖项将集中研究2004年北极春季发生的一个事件，当时观测到从中间层和下层热层（MLT）大量涌入的氮氧化物进入极地平流层，从而使平流层上层的氮氧化物混合比增加了4倍。这一行动反过来又导致这些海拔地区臭氧的局部催化减少超过60%。导致这种流入的过程是由高能电子沉淀（EEP）引发的，这种过程经常发生，但尚未得到令人满意的模型。拟议的工作将提高对EEP对大气的总体影响的理解，特别是对MLT与低层大气之间耦合的理解。对太阳-地球联系的全面描述需要对间接放大太阳和磁层输入影响的大气过程进行量化。这包括耦合大气不同区域的化学、辐射和动力过程之间的非线性反馈。大气对EEP的响应是太阳-地球联系的关键组成部分，并提供了探测潜在物理的自然手段。这一奖项将解决在解释和预测EEP对大气的影响方面的一个明显缺陷。由美国国家大气研究中心开发的全大气群落气候模式（WACCM）将与众多仪器的观测结果结合使用，以回答四个主要问题：1)为什么WACCM低估了2003-2004年北极冬季从MLT下降的活性奇氮（NOx）的数量；2)它在其他北极和南极冬季的表现如何？3)考虑到极地地区的极端变率，哪些统计数据集最适合用于研究与EEP相关的大气耦合过程？(4)极光电子沉淀和高能电子沉淀后的EEP对大气的影响是怎样的？

The award would study the downward transport from the mesosphere and lower thermosphere (MLT) of reactive nitrogen species (NOx) that are generated within the Arctic. The award would concentrate upon the study of an event that happened in the Arctic spring of 2004 for which an enormous influx of NOx from the mesosphere and lower thermosphere (MLT) was observed to enter the polar stratosphere, thus increasing the NOx mixing ratios in the upper stratosphere by a factor of 4. This action in turn caused for those altitudes localized catalytic reductions in ozone of more than 60%. The processes leading to this influx, which were initiated by energetic electron precipitation (EEP), occur routinely and they have not yet been satisfactorily modeled. The proposed work would improve the understanding of EEP effects on the atmosphere in general, and the coupling between the MLT and the lower atmosphere in particular. A comprehensive description of Sun-Earth connections requires the quantification of the atmospheric processes that indirectly amplify the effects of solar and magnetospheric input. This includes nonlinear feedbacks between chemical, radiative, and dynamical processes that couple different regions of the atmosphere. The atmospheric response to EEP is a key component of Sun-Earth connections and provides a natural means of probing the underlying physics. This award would address an obvious deficiency with regard to the explanation and prediction of the effects of EEP on the atmosphere. The Whole Atmosphere Community Climate Model (WACCM) developed by the National Center of Atmospheric Research would be used in conjunction with observations from numerous instruments to answer four primary questions: 1) Why does WACCM underestimate the amount of reactive odd nitrogen (NOx) that descended from the MLT during the Arctic winter of 2003-2004; 2)How well does it perform during other Arctic and Antarctic winters? 3), Given the extreme variability in the polar region, what statistical data sets are optimal for examining the atmospheric coupling processes that are relevant to EEP? and 4) What are the atmospheric effects of EEP after auroral electron precipitation and after higher energy electron precipitation?