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Study for the growth process of arctic PSC particles

北极PSC颗粒生长过程研究

基本信息

批准号：
11640431
负责人：
SHIBATA Takashi
金额：
$ 1.98万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640431/
关键词：
PSC Sandwich-structure lider nucleation ボックスモデルサンドウイッチ構造

项目摘要

A vertical sandwich structure of (type I) polar stratospheric clouds (PSCs), in which layers of relative depolarization are above and below a scattering layer, has frequently been observed by lidar at Ny-Ålesund, Svalbard when the stratospheric temnperature decreases to near the frost point of ice. Using lidar observations and backward trajectory analysis, we studied the time evolution of this structure and its temperature history. The main difference between the temperature history of PSCs in the scattering layer and those in the depolarization layer was the temperature at which the structure is observed. The small increase in the scattering ratio over time at the altitude of the depolarization maximum, implies a slow nucleation of solid particles. These lidar observations including temperature histories suggest that the sandwich structure arises from the external mixing of two different types of particles. A large fraction of liquid particles, grown at low temperature, constitutes the scattering layer, while at higher temperatures, a very small fraction of solid particles is responsible for the depolarization layer.A new model to simulate growth of PSC particles was constructed with using Lagrangean scheme in radial space of the particle radius. This model can simulate the growth and evaporation of externally mixed STS particles and NAT particles. The performance of the model was confirmed to be useful in PSC simulation within the photochemical model and interpretation of lidar data.

当平流层温度降低到接近冰霜点时，斯瓦尔巴群岛尼奥勒松的激光雷达经常观测到（I型）极地平流层云（PSC）的垂直夹层结构，其中相对去极化层位于散射层之上和之下。利用激光雷达观测和后向轨迹分析，我们研究了该结构的时间演化及其温度历史。散射层中的 PSC 和去偏振层中的 PSC 的温度历史之间的主要区别在于观察结构的温度。在去极化最大值高度处，散射比随时间的小幅增加意味着固体颗粒的成核缓慢。这些包括温度历史的激光雷达观测结果表明，夹层结构是由两种不同类型颗粒的外部混合产生的。低温下生长的大部分液体颗粒构成了散射层，而在较高温度下，极小部分固体颗粒则形成了去极化层。在颗粒半径的径向空间中，利用拉格朗日格式构建了模拟PSC颗粒生长的新模型。该模型可以模拟外部混合的STS颗粒和NAT颗粒的生长和蒸发。该模型的性能被证实可用于光化学模型内的 PSC 模拟和激光雷达数据的解释。