3D tomography for SCIAMACHY limb and nadir measurements: retrieval of stratospheric NO2, BrO and OClO profiles and their application for the investigation of stratospheric chemistry

卫星测量大大有助于了解与平流层臭氧损失有关的过程，例如通过对臭氧及其消耗物质进行全球和长期监测。例如，SCIAMACHY在ENVISAT上进行的边缘几何测量大大提高了对BrO和OClO等物种垂直分布的认识。然而，仍有一些重要的未决问题，例如不同种类的气溶胶和极地平流层云的氯活化过程。此外，寿命很短的物种在平流层溴收支中的作用或布鲁尔-多布森环流可能增强的影响也没有得到充分的了解。在全球范围内，臭氧消耗物种的垂直分布因太阳光照、大气化学和迁移而在空间和时间上有很大差异。特别强的梯度出现在曙暮光区附近或穿越平流层输送障碍（极涡边界、亚热带输送障碍）。这些地区是特别重要的化学和运输的平流层下部和对流层上部，因为它们分开的大尺度上的空气质量，但也使它们之间的exchanges.Standard 1-D剖面检索，假设水平均匀性，导致大的系统偏差，由于忽略了水平梯度的影响的测量。我们建议开发，改进和应用断层扫描轮廓检索算法，它最佳地结合了由SCIAMACHY肢体和最低点测量所提供的信息。将为科学家使命（2002-2012年）的10年开发一个改进的全球NO2、BrO和OClO三维平流层剖面数据集，与大气化学模拟进行比较，并应用于大气科学的某些问题。该项目开发的数据集将非常有助于调查平流层化学和迁移过程之间的复杂相互作用，并将有助于减少臭氧消耗物质分布的不确定性，特别是在横向不均匀性很大的区域。

Satellite measurements strongly contribute to the understanding of the processes related to stratospheric ozone loss, e.g. by global and long term monitoring of ozone and its depleting substances. For instance, measurements performed in limb geometry by SCIAMACHY on ENVISAT largely improved the knowledge about the vertical distribution of species like BrO and OClO only recently. However, there are still important open questions, like e.g. the chlorine activation processes on different kinds of aerosols and polar stratospheric clouds. Also, the role of very short lived species in the stratospheric bromine budget or the effects of a possible enhancement of the Brewer-Dobson circulation are not fully understood. Globally, the vertical distribution of ozone depleting species varies significantly in space and time due to solar illumination, atmospheric chemistry and transport. Especially strong gradients occur near the twilight zone or across stratospheric transport barriers (polar vortex boundary, subtropical transport barriers). These regions are of particular importance for chemistry and transport of the lower stratosphere and upper troposphere, since they separate air masses on large scales but also enable exchange between them.Standard 1-D profile retrievals, which assume horizontal homogeneity, result in large systematic biases due to neglecting the effect of horizontal gradients on the measurement. We propose to develop, improve and apply a tomographic profile retrieval algorithm, which optimally combines the information provided by the SCIAMACHY limb and nadir measurements. An improved global dataset of 3D stratospheric profiles for NO2, BrO and OClO for the 10 years of the SCIAMACHY mission (2002-2012) will be developed, compared to atmospheric chemistry simulations and applied to selected questions of atmospheric science. The dataset developed in this project will be very useful for investigating the complex interplay of stratospheric chemistry and transport processes, and will help to reduce the uncertainties in the distribution of ozone depleting species, in particular for regions with large horizontal inhomogeneity.