Observations and Modeling of Increased Nitric Oxide in the Antarctic Polar Middle Atmosphere Associated With Geomagnetic Storm-Driven Energetic Electron Precipitation
Observations and Modeling of Increased Nitric Oxide in the Antarctic Polar Middle Atmosphere Associated With Geomagnetic Storm-Driven Energetic Electron Precipitation
复制标题
与地磁风暴驱动的高能电子降水相关的南极极地中层大气中一氧化氮增加的观测和模拟
DOI：
10.1029/2018ja025507
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Newnham D
中科院分区：
文献类型：
--
作者：
Newnham D
在极地中高层大气中产生的高能粒子降水的一氧化氮（NO）消耗臭氧在中层，并在冬季极地涡旋的垂直传输，在平流层。在地磁暴期间，30- 1，000 keV电子的中能电子电离可能在中间层NO的产生中起重要作用。然而，问题仍然是直接NO生产的相对重要性，由极光电离在60-90公里的高度与间接NO起源于90公里以上。我们调查了2013-2014年期间南半球中层和低热层NO变化的潜在驱动因素。南极洲的两个冬季出现了截然不同的地磁活动，2013年冬季出现了更多的中度风暴。将来自南极洲哈雷的地面毫米波NO观测结果与太阳掩星冰实验（SOFIE）星载光谱仪的测量结果进行比较。来自两个观测数据集的65-140 km高度范围内的部分柱没有显示出较大的逐日变化和显著的不一致，哈雷值平均比相应的SOFIE数据高49%。SOFIE NO数密度，在地磁纬度−59°至−65°的纬向平均值，在2013年冬季比2014年高出3 × 108/cm 3。与新版本的全大气社区气候模式（包括详细的D区域离子化学（WACCM-SIC）和电离率）的比较表明，该模型低估了冬季低层中间层的NO，而热层丰度过高。这表明需要进一步改进和验证WACCM-SIC在电离层电离、热层NO化学和垂直输运方面的作用。
Nitric oxide (NO) produced in the polar middle and upper atmosphere by energetic particle precipitation depletes ozone in the mesosphere and, following vertical transport in the winter polar vortex, in the stratosphere. Medium‐energy electron (MEE) ionization by 30–1,000 keV electrons during geomagnetic storms may have a significant role in mesospheric NO production. However, questions remain about the relative importance of direct NO production by MEE at altitudes ~60–90 km versus indirect NO originating from auroral ionization above 90 km. We investigate potential drivers of NO variability in the southern‐hemisphere mesosphere and lower thermosphere during 2013–2014. Contrasting geomagnetic activity occurred during the two austral winters, with more numerous moderate storms in the 2013 winter. Ground‐based millimeter‐wave observations of NO from Halley, Antarctica, are compared with measurements by the Solar Occultation For Ice Experiment (SOFIE) spaceborne spectrometer. NO partial columns over the altitude range 65–140 km from the two observational data sets show large day‐to‐day variability and significant disagreement, with Halley values on average 49% higher than the corresponding SOFIE data. SOFIE NO number densities, zonally averaged over geomagnetic latitudes −59° to −65°, are up to 3 × 108/cm3higher in the winter of 2013 compared to 2014. Comparisons with a new version of the Whole Atmosphere Community Climate Model, which includes detailedD‐region ion chemistry (WACCM‐SIC) and MEE ionization rates, show that the model underestimates NO in the winter lower mesosphere whereas thermospheric abundances are too high. This indicates the need to further improve and verify WACCM‐SIC with respect to MEE ionization, thermospheric NO chemistry, and vertical transport.