On the impact of the temporal variability of the collisional quenching process on the mesospheric OH emission layer: a study based on SD-WACCM4 and SABER
On the impact of the temporal variability of the collisional quenching process on the mesospheric OH emission layer: a study based on SD-WACCM4 and SABER
复制标题
DOI：
10.5194/acp-14-10193-2014
复制
发表时间：
2014-09
影响因子：
6.3
通讯作者：
S. Kowalewski;C. Savigny;M. Palm;I. Mcdade;J. Notholt
中科院分区：
文献类型：
--
作者：
S. Kowalewski;C. Savigny;M. Palm;I. Mcdade;J. Notholt
抽象的。中层OH Meinel辐射是许多专门针对这部分大气的理论和观测研究的主题。取决于初始振动水平的激发的高度考虑OH Meinel发射系统地转移，这具有重要的意义，考虑不同的过渡带的不同研究的相互比较。先前的模型研究表明，这些垂直位移基本上是由原子氧的碰撞淬火过程引起的。根据这一假设，最近的一项研究发现，在热带纬度不同的OH Meinel波段的垂直移动和原子氧浓度的变化之间存在连贯的季节性。尽管上述假说的一致发现，它不能排除的实际时间变化的垂直移动之间的不同OH Meinel带可以另外控制，甚至由其他过程占主导地位。它仍然是一个悬而未决的问题，是否观察到的时间演化确实主要是由原子氧的碰撞淬火过程的调制控制。通过对SD-WACCM 4化学气候模式模拟结果的敏感性研究，对这一问题进行了探讨。从这项研究中，我们发现，所观察到的季节性垂直OH Meinel位移仅部分控制原子氧浓度的时间变化，而分子氧的垂直OH Meinel位移有另一个显着的影响。这特别是变得明显的垂直OH Meinel位移的日变化，这只揭示了一个贫穷的相关性与原子氧物种。此外，在H + O3源气体的变化提供了另一种机制，可以潜在地影响日变化。通过比较从SABER/TIMED卫星的临边辐射观测，这提供了一个解释不太明显的昼夜响应之间的变化O浓度和垂直OH Meinel位移。另一方面，在季节性时间尺度上，这两个量之间的一致性在SABER/TIMED中再次明显，但与我们的模型模拟相比不那么明显。
Abstract. The mesospheric OH Meinel emissions are subject of many theoretical and observational studies devoted to this part of the atmosphere. Depending on the initial vibrational level of excitation the altitude of the considered OH Meinel emission is systematically shifted, which has important implications for the intercomparison of different studies considering different transition bands. Previous model studies suggest that these vertical shifts are essentially caused by the process of collisional quenching with atomic oxygen. Following this hypothesis, a recent study found experimental evidence of a coherent seasonality at tropical latitudes between vertical shifts of different OH Meinel bands and changes in atomic oxygen concentrations. Despite the consistent finding of the above mentioned hypothesis, it cannot be excluded that the actual temporal variability of the vertical shifts between different OH Meinel bands may in addition be controlled or even dominated by other processes. It remains an open question whether the observed temporal evolution is indeed mainly controlled by the modulation of the collisional quenching process with atomic oxygen. By means of a sensitivity study which employs a quenching model to simulations made with the SD-WACCM4 chemistry climate model, we aim at assessing this question. From this study we find that the observed seasonality of vertical OH Meinel shifts is only partially controlled by temporal changes in atomic oxygen concentrations, while molecular oxygen has another noticeable impact on the vertical OH Meinel shifts. This in particular becomes evident for the diurnal variability of vertical OH Meinel shifts, which reveal only a poor correlation with the atomic oxygen species. Furthermore, changes in the H + O3 source gases provide another mechanism that can potentially affect the diurnal variability in addition. By comparison with limb radiance observations from the SABER/TIMED satellite this provides an explanation for the less evident diurnal response between changes in O concentrations and vertical OH Meinel shifts. On the other hand, at seasonal timescales the coherency between both quantities is again evident in SABER/TIMED but less pronounced compared to our model simulations.