Sensitivity of equatorial atomic oxygen in the MLT region to the 11-year and 27-day solar cycles
Sensitivity of equatorial atomic oxygen in the MLT region to the 11-year and 27-day solar cycles
复制标题
DOI：
10.1016/j.jastp.2016.11.003
复制
发表时间：
2017-09
影响因子：
1.9
通讯作者：
O. Lednyts'kyy;C. Savigny;M. Weber
中科院分区：
文献类型：
--
作者：
O. Lednyts'kyy;C. Savigny;M. Weber
本文报道了27天和11年太阳活动周期中地球大气中层/低热层（MLT）中原子氧（O）浓度（[O]）的变化特征。MLT [O]剖面是根据Envisat机载的扫描成像吸收光谱仪（SCIAMACHY）提供的2002年至2012年的绿色线（557.7 nm）夜光数据集检索的。利用互相关和叠加历元分析技术，在MLT [O]剖面的时间序列中识别出一个统计上显著的太阳27天特征（然后根据对太阳强迫的敏感性和相位关系进行量化）。这是第一次在这样的实验数据集的基础上确定MLT原子氧的太阳27天签名。利用互相关和多元线性回归分析技术，对11年时间尺度上[O]对太阳周期变率的敏感性进行了定量分析，得到的结果与已知研究一致，特别是表明[O]对太阳强迫的敏感性随高度的增加而增加。比较了27天和11年时间尺度上原子氧对太阳强迫的敏感性，发现在最后一个（第23个）11年太阳活动周期的下降阶段，两个敏感性在不确定性范围内是一致的。末次太阳活动极小期27天时间尺度上的[O]敏感度值低于下降期。还确定在11年时间尺度上，原子氧与太阳强迫同相（与模式结果一致），而响应太阳强迫的27天信号的时滞约为12 - 14天。
We report on 27-day and 11-year solar cycle signatures in atomic oxygen (O) concentrations ([O]) in the MLT (Mesosphere/Lower Thermosphere) region of the terrestrial atmosphere. MLT [O] profiles were retrieved on the base of green line (557.7 nm) nightglow data sets provided by the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) onboard Envisat from 2002 to 2012. A statistically significant solar 27-day signature was identified (and then quantified with respect to the sensitivity and phase relationship to solar forcing) in time series of MLT [O] profiles with use of cross-correlation and superposed epoch analysis techniques. It was the first identification of the solar 27-day signature in MLT atomic oxygen on the base of such experimental data sets. The sensitivity of [O] to solar cycle variability at the 11-year time scale was quantified with use of cross-correlation and multiple-linear regression analysis techniques, which yield results consistent with known studies and, particularly, indicate that the sensitivity of [O] to solar forcing increases with increasing altitude. A comparison of obtained values of atomic oxygen sensitivity in response to solar forcing at the 27-day and 11-year time scales reveals the fact that the sensitivities agree well to each other within their uncertainties during the descending phase of the last (23rd) 11-year cycle of solar activity, whereas the [O] sensitivity values at the 27-day time scale during the last solar minimum phase were lower than those ones during the descending phase. It was also determined that atomic oxygen is in-phase with the solar forcing (in agreement with model results) at the 11-year time scale, whereas the time lag of the 27-day signature in response to solar forcing was about 12 – 14 days.