Simultaneous In Situ Measurements within Polar Stratospheric Clouds of Particle Size, Number, Composition, Scattering Ratio, & of Gas Phase Concentrations of Nitric Acid &amp

关于极地平流层臭氧耗竭的重要细节仍然需要更完整的定量了解。在北极平流层尤其如此，那里臭氧的损失不像南极那么严重。极地平流层云（PSCs）中粒子的成核、生长、组成和沉降的微物理学是了解北极臭氧损失的关键领域之一。PSC粒子为激活氯所需的非均质化学提供了场所，氯随后会破坏臭氧。PSC颗粒所起的关键作用在北极最为明显，因为臭氧损失基本上是由温度（PSC的替代物）逐年调节的。PSC发生的频率、持续时间和时间在很大程度上决定了臭氧损失量。消除目前关于PSC形成温度、颗粒组成和颗粒相的一些不确定性，将允许对PSC处理的氯量进行更仔细的建模。该项目是在第三次欧洲平流层臭氧实验期间合作进行PSC特征的联合测量。这些仪器将被放置在一个气球吊舱上，它将同时在现场测量气溶胶浓度、大小、组成、去极化、后向散射以及硝酸和水的气相浓度。研究将集中在如何推断粒子的折射率，这是一个函数的组成。这些联合测量将是PSC颗粒存在的完整热力学环境的第一次直接测量，与气溶胶大小、浓度、组成、相位和光学性质的表征相一致。这些测量应该揭示被测psc与其环境的热力学平衡程度，HNO3水合物的形成程度，以及缩合HCI的丰度，HCI是氯活化的重要物质。

Important details concerning polar stratospheric ozone depletion are still required for a more complete quantitative understanding. This is particularly true in the Arctic stratosphere where the loss of ozone is not as severe as in the Antarctic. The microphysics of the nucleation, growth, composition, sedimentation of particles in polar stratospheric clouds (PSCs) is one of the critical areas for understanding Arctic ozone loss. PSC particles provide sites for the heterogeneous chemistry required to activate chlorine, which then destroys ozone. The pivotal role played by PSC particles is most evident in the Arctic when ozone loss is essentially modulated by temperature, a surrogate for PSCs, from year to year. The frequency, duration, and timing of PSC occurrence determines to a large extent the amount of ozone loss. Removing some of the present uncertainties concerning PSC formation temperatures, particle composition, and particle phase will permit more careful modeling of the amount of chlorine processed by PSCs. This project is to collaborate on joint measurements of PSC characteristics during the Third European Stratospheric Experiment on Ozone. The instruments will be flown onto one balloon gondola which will simultaneously measure, in situ, aerosol concentration, size, composition, depolarization, backscattering, and gas phase concentrations of nitric acid and water. The investigation will focus on methods to infer particle index of refraction, which is a function of composition. These joint measurements will be the first direct measurements of the complete thermodynamic environment in which PSC particles exist, coincident with a characterization of aerosol size, concentration, composition, phase, and optical properties. These measurements should reveal the extent to which the measured PSCs are in thermodynamic equilibrium with their environment, which hydrates of HNO3 are formed, and the abundance of condensed HCI, an important species for chlorine activation.