The global distribution of thermospheric odd nitrogen for solstice conditions during solar cycle minimum
The global distribution of thermospheric odd nitrogen for solstice conditions during solar cycle minimum
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太阳周期最小值期间至日条件下热层奇氮的全球分布
DOI：
10.1029/ja089ia03p01725
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发表时间：
1984
影响因子：
--
通讯作者：
A. Stewart
中科院分区：
文献类型：
--
作者：
J. Gérard;R. Roble;D. Rusch;A. Stewart
本文建立了70 ~ 360 km范围内次要中性组分N（2D）、N（4S）和NO的二维模式，并用于研究太阳活动周期极小期内冬至条件下这些组分的全球分布。对于背景性质的纬向平均环流，温度和主要的中性成分在热层的组成结构是从耦合动力学化学模式计算的Roble和Kasting（本期）。模式中考虑了次要中性组分的纬向环流和垂直环流以及垂直分子扩散和涡动扩散的输运。考虑了太阳电离和太阳+极光电离的次要中性成分的计算分布。结果表明，夏季至冬季极纬环流将NO和N（4S）穿过太阳终端进入极夜区，在极夜区存在向下向中间层的垂直输送。计算的纬度分布的NO在低热层的太阳电离的情况下，不同意纬度NO分布通常测量的大气探测器卫星。为了获得计算和观察到的结构之间的协议，它是必要的，包括电离和电离源，由于极光粒子沉淀。温度和成分结构以及高纬加热引起的环流变化和粒子诱导产生的N（2 D）和N（4 S）都联合收割机使计算的NO结构与观测结果更好地吻合。涡流扩散系数的选择严格控制热层一氧化氮向下流入中间层。模式表明，冬季高纬度地区的奇氮浓度完全受粒子降水和输送过程的控制。
A two-dimensional model of the minor neutral constituents N(²D), N(4S), and NO from 70 to 360 km is formulated and used to investigate the global distributions of these species for December solstice conditions during solar cycle minimum. For background properties the zonally averaged circulation, temperature, and compositional structure of major neutral constituents in the thermosphere are obtained from the coupled dynamical chemical model calculations of Roble and Kasting (this issue). Transport of the minor neutral constituents by both the meridional and vertical circulation and vertical molecular and eddy diffusion are considered in the model. The calculated distributions of the minor neutral constituents for solar ionization only and for solar plus auroral ionization are considered. The results show that the summer-to-winter pole meridional circulation transports both NO and N(4S) across the solar terminator into the polar night region where there is a downward vertical transport toward the mesosphere. The calculated latitudinal distribution of NO in the lower thermosphere for the solar-ionization-only case does not agree with the latitudinal NO distribution usually measured by the Atmosphere Explorer satellites. To obtain agreement between the calculated and observed structure, it is necessary to include ionization and dissociation sources due to auroral particle precipitation. The temperature and compositional structure and the circulation changes caused by high-latitude heating and the particle-induced production of N(²D) and N(4S) all combine to bring the calculated NO structure into better agreement with observations. The choice of the eddy diffusion coefficient critically controls the downward flow of thermospheric nitric oxide into the mesosphere. The model shows that the odd nitrogen densities at high winter latitudes are entirely controlled by particle precipitation and transport processes.