Vienna horizontal and vertical distribution observations of nitrogen dioxide and aerosols

拟议项目的总体目标是提高我们目前对人类造成的大型集聚地区空气污染的认识。对二氧化氮(NO2)和气溶胶数量的调查将基于奥地利维也纳两个不同地点的两台多轴差分光学吸收光谱(MAX-DOAS)仪器的光谱测量结果，这些仪器具有理想的测量条件。MAX-DOAS仪器是天顶散射光DOA和离轴DOA的发展，它允许在不同的观察方向上进行测量，从而获得关于对流层中痕量气体和气溶胶的水平和垂直变化的信息。几何近似和在Bremian高级Max-DOAS检索算法(BRAAM)中实现的最优估计方法将被用于反演对流层柱和NO2和气溶胶的垂直剖面。垂直剖面提供了与维也纳现场测量相比较的额外信息。从MAX-DOA中提取的高度平均对流层垂直痕量气柱以及气象测量(例如，风速、风向)允许在水平水平上监测城市背景、交通繁忙的道路和工业点源的空气污染物(NO2和气溶胶)。拟议的长期测量(两年以上)将为分析维也纳上空空气污染物的时间变异性提供宝贵的数据集。此外，这些数据将用于与希腊雅典和德国不来梅的MAX-DOAS观测结果进行比较，以调查不同纬度污染地点以及气象和光化学制度之间的异同。NO2的对流层垂直柱还将允许对OMI、GOME-2和Tropomi仪器的卫星测量进行验证，并与模型模拟进行比较，例如哥白尼大气监测服务。由于这两台仪器覆盖几个方位方向的部分重叠视场的测量结果以及现场测量提供了大量关于NO2空间分布的信息，将尝试使用层析成像方法为维也纳制作空气污染的空间分辨率图像。该项目的结果将提供关于城市环境中NO2和气溶胶的水平和垂直分布的信息。除了在痕量气体反演方面的改进外，结果还将为模型社区提供重要信息，因为NO2的垂直剖面是对现场仪器的点测量的有益补充。

The overall goal of the proposed project is to improve our current knowledge of air pollution in large agglomerations caused by mankind. The investigation of nitrogen dioxide (NO2) and aerosol amounts will be based on spectral measurements from two Multi AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) instruments located at two different sites with ideal measurement conditions in Vienna, Austria. The MAX-DOAS instrument is an advancement of the zenith scattered light DOAS and Off-Axis DOAS that allows for measurements at different viewing directions and thus, obtaining information about the horizontal and vertical variations of trace gases and aerosols in the troposphere.The geometrical approximation and an optimal estimation method implemented in the Bremian advanced MAX-DOAS Retrieval Algorithm (BREAM) will be used to retrieve tropospheric columns and vertical profiles of NO2 and aerosols. The vertical profiles provide additional information for the comparison with in-situ measurements in Vienna.The altitude-averaged tropospheric vertical trace gas columns retrieved from MAX-DOAS together with meteorological measurements (e.g. wind speed, wind direction) allow the monitoring of air pollutants (NO2 and aerosols) for urban background, high-traffic roads, and industrial point sources on the horizontal level. The proposed long-term measurements (more than two years) will provide a valuable data set for analyzing the temporal variability of air pollutants over Vienna. Moreover, these data will be used for the comparison with MAX-DOAS observations in Athens, Greece, and Bremen, Germany to investigate similarities and differences between polluted sites at different latitudes and meteorological and photochemical regimes. Tropospheric vertical columns of NO2 will also allow the validation of satellite measurements from the OMI, GOME-2, and TROPOMI instruments as well as comparison with model simulations, for example from the COPERNICUS atmospheric monitoring service.As the measurements from the two instruments covering several azimuthal directions with partially overlapping fields of view together with in-situ measurements provide a multitude of information on the spatial NO2 distribution, an attempt will be made to develop a spatially resolved image of air pollution for Vienna using a tomographic imaging approach.The results of the project will provide information about the horizontal and vertical distributions of NO2 and aerosols over an urban environment. In addition to improvements in the trace gas retrieval, the results will also provide important information for the model community, as the vertical profiles of NO2 are a useful supplement to the point measurements of in-situ instruments.