CEDAR: Atmospheric Coupling via Energetic Electron Precipitation (EEP)

该项目将研究北极地区产生的活性氮物质从中间层和低热层向下迁移的情况。该奖项将集中研究2004年北极春季发生的一个事件，当时观测到大量氮氧化物从中间层和低热层流入极地平流层，从而使平流层上部的氮氧化物混合比率增加了4倍。 这一行动反过来又导致这些高度的臭氧局部催化还原超过60%。导致这种涌入的过程，这是由高能电子沉淀（EEP）发起的，经常发生，他们还没有得到令人满意的模拟。拟议的工作将提高对EEP对大气的影响的理解，特别是MLT和低层大气之间的耦合。要全面描述日地关系，就需要量化间接放大太阳和磁层输入效应的大气过程。这包括耦合大气不同区域的化学、辐射和动力学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学的自然手段。这一裁决将解决在解释和预测EEP对大气层的影响方面的一个明显缺陷。利用美国国家大气研究中心（NationalCenterofAtmosphericResearch）开发的全大气群落气候模式（WACCM），结合多台仪器的观测资料，回答了4个主要问题：1）为什么WACCM低估了2003-2004年北极冬季从MLT沉降下来的活性奇氮（NOx）的数量; 2）在其他北极和南极的冬天，它的表现如何？3），鉴于极地地区的极端变化，什么样的统计数据集是最佳的检查大气耦合过程，是相关的EEP？4）极光电子沉降后和高能电子沉降后EEP的大气效应是什么？

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?