Aerosols from the Asian monsoon in the upper troposphere: sources, evolution, impacts

对流层上层亚洲季风产生的气溶胶：来源、演化、影响

• 批准号: 461442122
• 负责人: Privatdozent Dr. Michael Höpfner
• 金额: --
• 依托单位: IMK - Atmosphärische Spurengase und Fernerkundung
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/461442122?language=en
• 关键词: Aerosols; Asian; monsoon; upper; troposphere

Each year, from June till September, a layer of enhanced aerosol loading at 14–18 km altitude resides in a large area extending from the Mediterranean to the western Pacific - the Asian Tropopause Aerosol Layer (ATAL). There are large uncertainties about the composition of these particles as well as their significance for the radiative balance in this sensitive altitude region. The only airborne observations from deep inside this layer have been acquired during the StratoClim campaign based in Kathmandu in 2017. Based on data from the infrared spectrometer GLORIA on the research aircraft Geophysica, we discovered that solid ammonium nitrate (AN) particles account for a considerable part of the aerosol mass. Due to the unique capability of GLORIA to observe simultaneously the precursor gas ammonia (NH3) at these altitudes, we showed that the AN aerosol layer is fed by convection injecting large amounts of NH3 from the surface into the upper troposphere. It has also been demonstrated that solid AN particles count among the most efficient ice nuclei present in the atmosphere. Contributing to the PHILEAS campaign, we propose a common effort of atmospheric modelling and observations to better constrain the composition, origin, impacts and fate of ATAL particles - especially with regard to their evolution as well as their influence on the Northern Hemisphere upper troposphere and lower stratosphere. By acquiring measurements of monsoon-influenced air-masses over the eastern Mediterranean as well as outflow over the northern Pacific we will be able to analyse air with processed aerosol and trace-gas content, thereby complementing the StratoClim observations from deep inside the monsoon. To detect and quantify the likely smaller amounts of aerosol and trace gases in the outflow, we propose to improve the GLORIA data retrieval of NH3 and AN, amongst others, by utilizing spectroscopic data which has become available only recently. Further, we propose to expand the analysis of GLORIA spectra to sulfate aerosols as well as their precursor gas SO2. On the modelling side, we will further develop the ICON-ART global weather and climate model system for simulating the ATAL including various aerosol types (nitrate, ammonium, sulphate, organics, dust), thereby considering the high ice nucleating potential of solid AN. Model runs will be performed to achieve a global overview over the development of the ATAL during the time of the monsoon 2023, as well as detailed cloud resolving views on the aerosol-cloud-radiation interactions tailored to relevant campaign periods. Beyond the direct analysis of the PHILEAS campaign, this work will lay the foundation for improved aerosol retrieval from airborne GLORIA observations of previous and future HALO campaigns as well as satellite observations. Further it will enable ICON-ART, one of the central climate model systems in Germany on simulating aerosol processes as well as aerosol/cloud interactions connected to the ATAL.

每年6月至9月，在从地中海延伸到西太平洋的一大片地区，在14-18公里高度存在一层增强的气溶胶-亚洲对流层顶气溶胶层。关于这些粒子的组成及其对这一敏感高度区域辐射平衡的重要性，存在很大的不确定性。唯一来自该层深处的空中观测是在2017年加德满都的StratoClim活动期间获得的。根据研究飞机Geopeclica上的红外光谱仪格洛丽亚的数据，我们发现固体硝酸铵（AN）颗粒占气溶胶质量的相当大一部分。由于格洛丽亚的独特能力，同时观察前体气体氨（NH3）在这些高度，我们表明，AN气溶胶层是由对流注入大量的NH3从表面到对流层上部。它也已被证明，固体AN粒子计数中最有效的冰核存在于大气中。 为促进PHILEAS活动，我们提出了一个共同的努力，大气建模和观测，以更好地约束的组成，起源，影响和ATAL粒子的命运-特别是关于它们的演变以及它们对北方半球对流层上部和平流层下部的影响。通过获得地中海东部受季风影响的气团以及北方太平洋外流的测量结果，我们将能够分析具有处理过的气溶胶和痕量气体含量的空气，从而补充来自季风深处的StratoClim观测。为了检测和量化可能的少量的气溶胶和微量气体的流出，我们建议提高格洛丽亚数据检索的NH3和AN，除其他外，利用光谱数据，最近才成为可用的。此外，我们建议扩展格洛丽亚光谱的分析，硫酸盐气溶胶以及它们的前体气体SO2。在模拟方面，我们会进一步发展ICON-ART全球天气及气候模式系统，以模拟包括各种气溶胶类型（硝酸盐、铵、硫酸盐、有机物、尘埃）的ATAL，从而考虑固体硝酸盐的高冰成核潜力。将进行模型运行，以实现对2023年季风期间ATAL发展的全球概述，以及针对相关活动期间定制的气溶胶-云-辐射相互作用的详细云解析视图。除了对PHILEAS活动进行直接分析之外，这项工作还将为改进以前和今后HALO活动机载格洛丽亚观测以及卫星观测的气溶胶反演奠定基础。此外，它还将使德国的中央气候模式系统之一ICON-ART能够模拟气溶胶过程以及与ATAL相连的气溶胶/云相互作用。