Investigation of the photochemistry of oxygen species in the mesopause region

原子氧（O）是地球中层顶区最重要的化学成分之一。它对这一大气区域的能量平衡起着至关重要的作用。由于其化学寿命长，它能够在很长的距离上传输化学势能。它间接参与中层顶区域的辐射冷却，并直接耦合到不太丰富的臭氧，这反过来又控制着中间层的非绝热太阳加热。在中层顶区域的O测量的数量是相当有限的，大多数现有的观测是基于O2，O和OH气辉排放的测量。这些测量是间接测量，通常需要大量的光化学速率常数的知识。现有的研究提供了明确的证据表明，目前使用的模型来描述O2的A带，O绿色线和OH Meinel的排放，这都是由原子氧驱动，是不一致的。在这一建议的框架内，我们计划调查现有的光化学模型的一致性，上述三个气辉排放。这将利用对所有三种排放的同步卫星观测和专用模型模拟的协同作用来实现。将使用的卫星测量是利用环境卫星航天器上的SCIAMACHY（用于大气特征分析的扫描成像吸收光谱仪）仪器进行的，该航天器于2002年至2012年运行。SCIAMACHY是唯一适合于这一目的的，因为它具有广泛的光谱范围，它涵盖了与此提案相关的所有气辉发射，并提供了这些发射的同步和光谱分辨观测。计划中的模型模拟将使用一套已建立的光化学和全球模型进行。使用逆建模方法，我们计划进行优化的光化学模型参数，同时最大限度地减少模型结果和SCIAMACHY观测之间的差异。此外，我们计划进行一个彻底的表征的空间和时间变化的O在中层顶区域，特别关注太阳的影响和潜在的长期变化在2002年至2012年期间。此外，我们的目标是改善现有的气候模式的O在中层顶区（例如，MSIS）-在不同方面显然是不够的-使用O时间序列中得出的这个项目。申请人是各自主要研究领域的知名专家，在利用地面气辉排放进行卫星遥感和大气建模领域分别拥有长期经验。

Atomic oxygen (O) is one of the most important chemical constituents of the terrestrial mesopause region. It plays an essential role for the energy balance of this atmospheric region. Due to its long chemical lifetime it is capable of transporting chemical potential energy over large distances. It participates indirectly in the radiative cooling of the mesopause region and it is directly coupled to the less abundant ozone, which in turn governs diabatic solar heating of mesosphere. The number of O measurements in the mesopause region is rather limited, and most of the available observations are based on measurements of the O2, O and OH airglow emissions. These measurements are indirect measurements and generally require knowledge of a large number of photochemical rate constants. Existing studies provide clear evidence that the currently used models to describe the O2 A-band, the O green line and the OH Meinel emissions, which are all driven by atomic oxygen, are inconsistent. Within the frame of this proposal we are planning on investigating the consistency of the existing photochemical models of the three airglow emissions mentioned. This will be done using the synergy of simultaneous satellite observations of all three emissions and dedicated model simulations. The satellite measurements to be used were carried out with the SCIAMACHY (Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY) instrument on the Envisat spacecraft, which operated from 2002 to 2012. SCIAMACHY is uniquely suited for this purpose, because with its broad spectral range it covers all the airglow emissions relevant for this proposal and provides simultaneous and spectrally resolved observations of these emissions. The planned model simulations will be performed with a suite of established photochemical and global models. Using an inverse modelling approach, we plan on carrying out an optimization of photochemical model parameters by simultaneously minimizing the differences between model results and the SCIAMACHY observations. In addition, we plan on performing a thorough characterization of the spatial and temporal variability of O in the mesopause region, with particular focus on solar influence and potential long-term variations over the period from 2002 to 2012. Furthermore, our aim is to improve the existing climatological models of O in the mesopause region (e.g., MSIS) - which are clearly inadequate in different respects - using the O time series derived within this project. The applicants are established experts in their main research areas and have long-time experience in the area of satellite remote sensing using terrestrial airglow emissions and atmospheric modelling, respectively.