The effects of organic material on warm and cold cloud formation: from the laboratory to regional and global impacts

有机物质对暖云和冷云形成的影响：从实验室到区域和全球影响

• 批准号: NE/L007827/1
• 负责人: Gordon McFiggans
• 金额: $ 85.33万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FL007827%2F1
• 关键词: effects; organic; material; warm; cold

Clouds have a profound influence on weather and climate. Formation of cloud droplets by condensation of water vapour on particles has been studied for many decades. For inert involatile particles, this process and its impacts are relatively well understood. However, a substantial proportion of fine particle material can evaporate under some atmospheric conditions. Our recent Nature Geoscience Letter suggests that the role of this fraction on cloud droplet formation is large enough to be globally significant, is not normally considered in cloud parcel models and is completely untreated in large-scale models. This results from the co-condensation of partly volatile material along with the water vapour during droplet activation. Indirect evidence supports this effect, but direct measurements are unavailable. There has also been considerable interest in the potential role of amorphous "glassy" particles as seeds for ice crystals in cold and mixed-phase clouds. The Nature publication and subsequent work by project partner Virtanen identified that secondary organic aerosol from both biogenic and anthropogenic precursors could exist in an amorphous state dependent on relative humidity and temperature. The impact of glassy particles as ice nuclei is potentially very significant, but direct evidence is currently confused and realistic supporting measurements are sparse. It is proposed to quantify the impacts of organic components on warm and cold cloud formation by both processes through simulation chamber measurements, to use the measurements to evaluate a recently developed model treatment, to parameterise the model and use the parameterisation to quantify the regional impacts on cloud physical and radiative properties.We have conducted proof of concept laboratory work showing that we are able to study both processes. We have coupled the Manchester Aerosol Chamber (MAC), where we can make particles from the atmospheric chemistry of both natural plant emissions and man-made emissions, to the Manchester Ice Cloud Chamber (MICC), where we can form a cloud under reasonable atmospheric conditions. We have further measured the changes in the effectiveness of the particles to act as seeds for liquid cloud droplets, cloud condensation nuclei (CCN), along with the volatility, composition and phase behaviour. We propose to build on this proof-of-concept to systematically quantify the effects in a range of atmospherically-representative systems and quantify their impacts.The proposed work will be carried out in 4 parts. The first two are laboratory-based with numerical model interpretation and the second two solely use numerical modelling: i) quantification of the effect of organic vapours in two instruments that are used in the field and laboratory, one measuring particle water uptake below 100% RH and the other the ability to form a cloud droplet just above 100% RH. Particles will be exposed to controlled concentration of semi-volatile vapour and introduced into the instruments. Detailed flow modelling of the second instrument will be carried out, in collaboration with the author as project partner.ii) involves the coupling of the MAC and MICC chambers as in the proof-of-concept, but covering particles formed in a wide range of natural, manmade and mixed systems. We will measure all relevant parameters to quantify the formation of warm and cold clouds under a reasonable range of atmospheric conditions.iii) informed by the experiments, the effects of organic compounds on warm and cold clouds will be included in a numerical model and this will be used to develop physically-based parameterisations for use in large-scale models.iv) the parameterised process description will be used in large-scale models informed by our project partner Nenes to estimate the impact on cloud properties and radiation, hence quantifying the couplings between organic compounds and weather and climate under representative conditions.

云对天气和气候有深远的影响。水蒸气凝结在粒子上形成云滴的研究已经有几十年的历史了。对于惰性非挥发性粒子，这一过程及其影响是相对较好的理解。然而，在某些大气条件下，相当大比例的细小颗粒物质会蒸发。我们最近的《自然地球科学通讯》指出，这一部分在云滴形成中的作用大到足以在全球范围内具有重要意义，通常不会在云团模型中考虑，在大型模型中也完全没有处理。这是由于在液滴激活过程中，部分挥发性物质与水蒸气发生共冷凝。间接证据支持这一效应，但无法进行直接测量。在冷云和混合相云中，无定形“玻璃状”粒子作为冰晶种子的潜在作用也引起了相当大的兴趣。《自然》出版物和项目合作伙伴Virtanen随后的工作确认，生物和人为前体的二次有机气溶胶可能以无定形状态存在，取决于相对湿度和温度。玻璃粒子作为冰核的影响可能非常重大，但直接证据目前尚不清楚，现实的支持测量数据也很少。我们建议通过模拟室的测量来量化有机成分对两个过程形成的冷云和暖云的影响，利用这些测量来评估最近发展的模式处理，将模式参数化，并使用参数化来量化区域对云物理和辐射特性的影响。我们已经进行了概念验证实验室工作，表明我们能够研究这两个过程。我们将曼彻斯特气雾室(MAC)与曼彻斯特冰云室(MICC)连接起来，在那里我们可以从天然植物排放和人为排放的大气化学物质中制造颗粒，在那里我们可以在合理的大气条件下形成云。我们进一步测量了作为液态云滴、云凝结核(CCN)种子的粒子的有效性以及挥发性、组成和相行为的变化。我们建议在这个概念验证的基础上，系统地量化一系列大气代表性系统中的影响，并量化它们的影响。拟议的工作将分四个部分进行。前两项是以实验室为基础，进行数值模式解释，后两项仅使用数值模拟：i)在野外和实验室使用的两台仪器中对有机蒸气的影响进行量化，一台测量相对湿度低于100%的颗粒吸水率，另一台测量相对湿度略高于100%相对湿度的云滴的形成能力。颗粒将暴露在受控浓度的半挥发性蒸汽中，并被引入仪器中。将与作者作为项目合作伙伴合作，对第二个仪器进行详细的流动模拟。ii)如概念验证一样，涉及MAC和MICC室的耦合，但涵盖在各种天然、人造和混合系统中形成的颗粒。我们将测量所有相关参数，以量化在合理范围的大气条件下形成的冷暖云。iii)根据实验，有机化合物对冷暖云的影响将被包括在一个数值模式中，并将用于开发用于大型模式的基于物理的参数化。iv)参数化过程描述将用于由我们的项目合作伙伴Nenes提供的大型模式，以估计对云特性和辐射的影响，从而量化在典型条件下有机化合物与天气和气候之间的耦合。

项目成果

Measured particle water uptake enhanced by co-condensing vapours

• DOI: 10.5194/acp-18-14925-2018
• 发表时间: 2018-06
• 期刊: Atmospheric Chemistry and Physics
• 影响因子: 6.3
• 作者: Dawei Hu;D. Topping;G. Mcfiggans

A parameterisation for the co-condensation of semi-volatile organics into multiple aerosol particle modes

半挥发性有机物共凝结成多种气溶胶颗粒模式的参数化

• DOI: 10.5194/gmd-2017-123
• 发表时间: 2017
• 作者: Crooks M

The efficiency of secondary organic aerosol particles to act as ice nucleating particles at mixed-phase cloud conditions

混合相云条件下二次有机气溶胶颗粒充当冰核颗粒的效率

• DOI: 10.5194/acp-2017-1223
• 发表时间: 2018
• 作者: Frey W

The efficiency of secondary organic aerosol particles acting as ice-nucleating particles under mixed-phase cloud conditions

• DOI: 10.5194/acp-18-9393-2018
• 发表时间: 2018-07
• 期刊: Atmospheric Chemistry and Physics
• 影响因子: 6.3
• 作者: W. Frey;Dawei Hu;J. Dorsey;M. Alfarra;A. Pajunoja;A. Virtanen;P. Connolly;G. Mcfiggans

Competition for water vapour results in suppression of ice formation in mixed phase clouds

水蒸气的竞争导致混合相云中冰的形成受到抑制

• DOI: 10.5194/acp-2017-673
• 发表时间: 2017
• 作者: Simpson E