Quantifying the light scattering and atmospheric oxidation rate of real organic films on atmospheric aerosol

这里提出的建议是重要的量化界面化学在大气中是如何重要的现代气候变化的评估。它依赖于大气科学的三个方面：1）大气气溶胶是悬浮在空气中的微小固体或液体颗粒。它们来自人类活动（例如燃烧化石燃料）和自然（例如海浪），可以在大气中存在几分钟到几天。在评估人为因素对气候变化的影响时，这些气溶胶是一个很大的不确定性来源，因为它们强烈影响（I）反射回太空的光量（可能冷却地球）和（II）云的形成，以及它们反射回太空的阳光量（再次，可能冷却地球）。2)这些气溶胶中的一些具有有机材料的薄膜或涂层。由于这些气溶胶的大小与太阳光的波长相似，一层薄薄的涂层可以显着改变它们散射和“反射”太阳光的能力以及它们形成云的潜力。3)大气层有效地充当低温、稀释燃料、燃烧系统氧化从地球表面释放的化学物质。从地球表面释放的化学物质被氧化去除的速度对于理解大气的自我净化机制非常重要。以前，大气气溶胶薄膜的“替代物”已经被证明可能会改变云的光散射和云形成能力。这些替代物是从化学目录中选择的，并不代表大气中发现的混合物和种类。我们将使用从不同位置提取的 * 真实的 * 材料来表征在真实的大气气溶胶上形成的薄膜，确定它们的薄膜厚度、光散射能力以及它们在大气中的化学反应性。我们自己的初步工作表明，实验室代用薄膜并不能代表真实的大气。薄膜厚度对于计算其光散射能力至关重要，而光散射能力又对于计算散射回太空的阳光比例至关重要。化学反应性在决定膜的寿命方面是重要的，因为随着膜反应，颗粒的光学性质将显著改变。如果薄膜寿命比典型的气溶胶寿命长，则可以简单地将其包括在大气模型中，但如果薄膜寿命短得多，则可以忽略。然而，初步数据表明，它具有类似的寿命，这意味着需要对涂覆颗粒的光散射特性的 * 变化 * 进行建模。该项目代表了第一次对大气薄膜氧化和大气中真实的大气物质的光散射进行全面研究。实验和建模相结合的方法将允许演示（I）大气样品的核壳（薄膜行为），（II）计算其光学特性和大气顶部辐射平衡的变化。(III)测量大气氧化速率的膜和夹杂物在钴-碘导致复杂的气溶胶动力学模拟的复杂混合气溶胶。该提案还将继续开发两种新兴的令人兴奋的大气科学技术：激光捕获与米氏光谱和中子散射。这些技术在真实的时间内以正确的形态和前所未有的精度研究~ 10 nm厚的薄膜的能力是惊人的。该建议也将是一个很好的培训工具，为两个PDRAS在软物质，设施，大气实验科学与大气结果的真实的世界建模。信件os支持表明，最终用户的一些关闭数据与大都会。办公室（英国）和MPIC（德国）。

The proposal presented here is important for quantifying how interfacial chemistry in the atmosphere is important in the assessment of modern climate change. It relies on three aspects of atmospheric science1) Atmospheric aerosols are tiny solid or liquid particles suspended in air. They arise from human activity (e.g. burning of fossil fuels) and naturally (e.g. breaking ocean waves) and can exist in the atmosphere for minutes to days. These aerosol are a large source of uncertainty when assessing man-made contributions to climate change as they strongly influence (I) the amount of light reflected back to space (potentially cooling the planet) and (II) the formation of clouds, and how much sunlight they reflect back to space (again, potentially cooling the planet). 2) Some of these aerosol have thin films or coatings of organic material. As the size of these aerosol are similar to the wavelength of sunlight a thin coating can significantly alter their ability to scatter and 'reflect' sunlight and their potential to form clouds. 3) The atmosphere effectively acts as a low temperature, dilute fuel, combustion system oxidizing chemicals released from the Earth's surface. The rate at which chemicals released from the Earth's surface can be removed by oxidation is important in understanding the atmosphere's self-cleansing mechanism.Previously *proxies* of thin films on atmospheric aerosol have been shown to potentially alter the light scattering and cloud forming ability of clouds. These proxies have been chosen from a chemical catalogue and do not represent the mixture and variety found in the atmosphere. We will use *real* material extracted from different locations to characterize the thin films formed on real atmospheric aerosol, determine their film thicknesses, light scattering ability and their chemical reactivity in the atmosphere. Our own preliminary work demonstrates that laboratory proxy thin films are not representative of the real atmosphere. The film thicknesses are critical to the calculation of their light scattering ability which in turn is critical to calculation of the proportion of sunlight scattered back to space. The chemical reactivity is important in determining the lifetime of the film, because as the film reacts the optical properties of the particle will change significantly. If the film lifetime is longer than a typical aerosol lifetime then it can be simply included into atmospheric models, but if the film lifetime is much shorter then it may be ignored. However preliminary data suggests it is has a similar lifetime meaning the *changing* light scattering properties of a coated particle will need to be modelled.The project represents the first comprehensive study of atmospheric thin film oxidation and light scattering with real atmospheric matter from the atmosphere. The combined experimental and modelling approach will allow the demonstration of (I) core-shell (thin film behavior) from atmospheric samples, (II) calculation of their optical properties and change in radiative balance at the top of the atmosphere., (III) measurement of atmospheric oxidation rates of the film and inclusion in Co-I led complex aerosol kinetic modelling of complex mixture aerosol. The proposal will also continue to develop two emergent exciting techniques for atmospheric science: Laser trapping with Mie spectroscopy and neutron scattering. The ability of these technique to study films ~10nm thick in real time, with the correct morphology and with unprecedented precision is phenomenal. The proposal will also be an excellent training vehicle for two PDRAS in soft-matter, facility, and atmospheric experimental science with real world modelling of atmospheric outcomes.The data and model systems from this proposed work will be ready for including global climate models. The letters os support demonstrate that ends users for some off data with the Met. office(UK) and MPIC (Germany).