Studies on the density and formation mechanism of the solid PSC particles in the Arctic stratosphere

2003/2004年冬季，在北极平流层温度开始降低的12月底，在Ny-Aalesund开始进行激光雷达观测。我们为气球发射准备了OPC，并等待PSC观察的好时机。在这个冬天没有观察到PSC，因为从12月到1月平流层温度没有降低到足以形成PSC。然而，我们观察到的层增加去极化层（层的固体粒子）在海拔约35公里，从12月初。该高度的温度高于背景硫酸气溶胶的蒸发温度。在2000/2001年冬季也观测到了类似的层。虽然这一层的来源被认为是火箭排气或流星烟雾等，目前还没有确定。固体颗粒的半径相对较小，约为0.05 μm。2004/2005年冬季，我们在11月底至1月初继续观测了这类小粒子，并在此基础上对它们进行了研究。自12月底以来，平流层温度一直低于PSC形成温度。利用激光雷达和OPC技术，可以获得特别是在12月底PSC开始出现时的数据。我们现在正在研究数据。

In the winter 2003/2004,the lidar observations were started at Ny-Aalesund in the end of December when the temperature in the Arctic stratosphere began to be lowered. We prepared the OPC for the balloon launching, and waited the good timing for the PSC observation. PSCs were not observed in this winter because the stratospheric temperature had not been lowered enough for the formation of PSCs from December through January. However, we observed layer of increased depolarization layer (layer of solid particles) in the altitude around 35 km from the beginning of December. The temperature at this altitude is higher than the evaporation temperature of the background sulfuric acid aerosols. The similar layer was also observed in the winter of 2000/2001. Although the origin of this layer were assumed to be as rocket exhausts or meteor smoke, etc., it has not been identified, yet. The radius of the solid particles was though to be relatively small, or about 0.05 μm. Since this kind of small particles are suggested to be potential nuclei of solid PSCs, the data were quite useful for this study.In the winter 2004/2005,we continued observation from the end of November through the beginning of January. The stratospheric temperature has been lowered lower than the PSC formation temperature since the end of December. We could get the data especially when the PSCs start to appear in the end of December by lidar and OPC. We are now examining the data.