Study on inference of particle composition of the Polar Storatospheric Clouds observed with satellite sensors

1997年冬春初，改进的极地平流层大气光谱仪(ILAS)捕捉到了北半球的许多极地平流层云(PSC)事件。ILAS气溶胶消光系数和硝酸数据与过冷三元溶液(STS)、二水硝酸(NAD)和三水硝酸(NAT)粒子在平衡状态下的理论预测值进行了比较，以推断观测到的PSC粒子的化学组成。观测表明，1997年，冬季和初春期间，直到3月中旬，北极上空形成了含硝酸的固体和液体PSCS。1月中旬发现了一些典型的STS PSCs，尽管其中一些事件似乎涉及冰粒。在PSC季节后期观察到的大多数PSC具有含硝酸的水合物的特征。对温度历史的深入分析表明，1月份观测到的大多数STS粒子都经历了形成液体粒子所必需的热条件。

The Improved Limb Atmospheric Spectrometer (ILAS) captured many Polar Stratospheric Cloud (PSC) events in the Northern Hemisphere during the winter and early spring of 1997. The ILAS aerosol extinction coefficient and nitric acid data were compared with the theoretically predicted values for supercooled ternary solution (STS), nitric acid dihydrate (NAD) and nitric acid trihydrate (NAT) particles at equilibrium to infer the chemical composition of the observed PSC particles. The observations showed that in 1997, nitric acid-containing solid and liquid PSCs formed over the Arctic during winter and early spring, until mid-March. Some typical STS PSCs were found in mid-January, though some of the events seemed to involve ice particles. Most of the PSCs observed late in the PSC season had features of nitric acid-containing hydrates. An intensive analysis of the temperature histories suggested that most of the STS particles observed in January had experienced the thermal conditions necessary for the formation of liquid particles.