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The regional aerosol in eastern central china and its cloud microphysical and optical properties of haze at high relative humidities

高相对湿度下华中东部区域气溶胶及其云微物理和霾光学特性

基本信息

批准号：
46363278
负责人：
Professor Dr. Alfred Wiedensohler
金额：
--
依托单位：
Leibniz-Institut für Troposphärenforschung e.V. (TROPOS)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2007
资助国家：
德国
起止时间：
2006-12-31 至 2010-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/46363278?language=en
关键词：
regional aerosol eastern central china

项目摘要

Large areas of China suffer from heavy air pollution caused by the strong economic growth in the last two decades. Especially, regions such as the Pearl River Delta in Southern China and the eastern central region around Beijing underlie haze layers clearly visible from satellite observations. The reduced visibility and the large optical depth caused from high aerosol concentrations are strongly dependent on the ability to take up water (hygroscopicity). At relative humidities between 90 and 99%, the aerosol particles grow exponentionally. The hygroscopic behavior at relative humidities close to 100% is strongly linked to the particles ability to grow into cloud droplets at supersaturation. The strong anthropogenic emission of aerosol particles implies a change of the cloud droplet size distribution which increases the cloud albedo. This indirect aerosol effect leads to a general cooling of the atmosphere and is one of the most uncertain parameters with respect to global change. Especially in China, this impact is supposed to be very large, because of the high concentration of anthropogenically emitted particles. Within this project, the characterization of the particle number size distribution, the particle optical properties, their hygroscopic properties at high RH below supersaturation, their cloud nucleating properties above supersaturation, their subsequent activation dynamic growth, and their chemically size-resolved properties are planned to be characterized.

中国的大部分地区都遭受着过去二十年强劲的经济增长所造成的严重空气污染。特别是中国南方的珠江三角洲和北京周围的中东部地区，从卫星观测中可以清楚地看到雾霾层。高气溶胶浓度造成的能见度降低和光学厚度大，在很大程度上取决于吸收水分的能力（吸湿性）。在相对湿度为90%至99%时，气溶胶粒子呈指数增长。在接近100%的相对湿度下的吸湿行为与颗粒在过饱和下生长成云滴的能力密切相关。强的人为排放的气溶胶粒子意味着云滴的大小分布的变化，增加了云的能见度。这种间接的气溶胶效应导致大气普遍变冷，是全球变化方面最不确定的参数之一。特别是在中国，这种影响应该是非常大的，因为放射性颗粒的浓度很高。在这个项目中，颗粒的数量尺寸分布，颗粒的光学性能，其吸湿性能在高相对湿度低于过饱和，其云成核性能以上过饱和，其随后的激活动态增长，以及其化学尺寸分辨性能的表征计划进行表征。