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.

云对天气和气候产生了深远的影响。数十年来，已经研究了通过颗粒上的水蒸气凝结来形成云滴。对于惰性的纳入颗粒，该过程及其影响相对较充分地理解。但是，在某些大气条件下，很大一部分的细颗粒物质会蒸发。我们最近的自然地球科学字母表明，这一部分在云液滴形成中的作用足够大，可以在全球范围内具有重要意义，通常在云地块模型中不考虑，并且在大型模型中完全未经治疗。这是由于在液滴激活过程中部分挥发性材料以及水蒸气的共敏造成的。间接证据支持此效果，但直接测量不可用。对于冷和混合相云中的冰晶种子，对无定形“玻璃状”颗粒的潜在作用也引起了极大的兴趣。 Virtanen项目合作伙伴的自然出版物和随后的工作确定，来自生物源和人为先驱物质的二级有机气溶胶可能存在于非晶状态下，取决于相对湿度和温度。玻璃状颗粒作为冰核的影响可能非常重要，但是直接证据当前混淆且逼真的支撑测量很少。建议通过模拟室测量来量化有机成分对温暖和冷云形成的影响，以使用测量值评估最近开发的模型处理，以参数化模型并使用参数化来量化参数化对云的物理和辐射性能的影响。我们对概念实验室的工作进行了验证，以实现概念性实验室工作，以研究我们两者的过程都可以研究我们的过程。我们已经将曼彻斯特气溶胶室（MAC）耦合在一起，在那里我们可以从天然植物排放和人造排放的大气化学中制成颗粒，到曼彻斯特冰云室（MICC），我们可以在合理的大气条件下形成云。我们进一步衡量了颗粒充当液体云液滴，云凝结核（CCN）的种子的有效性的变化，以及挥发性，组成和相行为。我们建议以这种概念验证为基础，以系统地量化一系列大气代表性系统中的影响并量化其影响。拟议的工作将在4个部分中进行。前两个是基于实验室的数值模型解释，第二个仅使用数值建模：i）定量在现场和实验室中使用的两种仪器中有机蒸气的效果，一种测量颗粒水的吸收低于100％RH，而另一种则可以形成云液滴以上100％rh以上。颗粒将暴露于半挥发蒸气的受控浓度中，并引入仪器中。与作者合作作为项目合作伙伴，将进行第二个仪器的详细流程建模。我们将测量所有相关参数，以量化在合理的大气条件下的温暖和冷云的形成。III）在实验中导致的信息，有机化合物对温暖和冷云的影响将包括在数值模型中，并且将用于开发基于物理的参数，以便在大型尺度上使用较大的参数。在代表性条件下，对云特性和辐射的影响量化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

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

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