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消耗的重要细节仍然需要更全面的定量了解。在北极平流层尤其如此，那里的臭氧损失不像南极那么严重。极地平流层云中粒子的成核、生长、组成和沉积的微物理是理解北极臭氧损失的关键领域之一。PSC颗粒为激活氯所需的非均相化学提供了场所，氯随后破坏臭氧。PSC颗粒发挥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调节的，温度是PSC的替代品，年复一年。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因素，将允许对PSC处理的氯量进行更仔细的建模。该项目将在第三次欧洲平流层臭氧实验期间合作测量PSC特性。这些仪器将被送到一个气球吊舱上，该吊舱将同时原位测量气溶胶浓度、尺寸、成分、去极化、后向散射以及硝酸和水的气相浓度。这项研究将集中在推断粒子折射率的方法上，这是组成的函数。这些联合测量将是对PSC颗粒所在的完整热力学环境的首次直接测量，这与气溶胶的尺寸、浓度、成分、物相和光学性质的特征相一致。这些测量应该揭示所测量的PSCs与其环境处于热力学平衡的程度，形成HNO3的水合物，以及氯活化的重要物种--浓缩HCI的丰度。

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.