Observation of the nighttime variation of nitrogen oxides concentration in the stratosphere

本研究的目的是利用气球观测平流层氮氧化物浓度的夜间变化。平流层中氮氧化物的夜间变化是相当显着的，因为在夜间产生的N2O5，在硫酸气溶胶的存在下，HNO3的非均相过程转换建议发挥显着的作用，在平流层下部的臭氧消耗。为此，我们正在研制一台仪器，用光谱法观测NO_2、NO_3、臭氧和气溶胶的垂直分布。通过使用枯萎星作为光源，我们可以在一个晚上获得这些物种的5个以上的配置文件。通过数值计算，我们证实了这种观测的可能性。我们研制了一套星跟踪仪、包括望远镜和六色高分辨率光度计在内的光学系统、信号处理电子学和数据采集系统。在系统性能测试中，我们发现星跟踪器伺服控制不够稳定，无法获得高质量的数据。通过将伺服电机改为数控电机来提高星跟踪器的稳定性，我们认为可以对气球实验仪器进行改进。但由于仪器研制的滞后，在本项目研究期间无法进行气球观测。

The objective of this research is a balloon observation of the nighttime variation of nitrogen oxides concentration in the stratosphere. The nighttime variation of inventory of nitrogen oxides in the stratosphere is quite significant because the heterogeneous process to convert N2O5, which is generated in the nighttime, to HNO3 in the presence of sulfuric acid aerosol is suggested to play a significant role in the ozone depletion in the lower stratosphere. For this purpose, we are developing an instrument to observe vertical distribution of NO2, NO3, ozone and aerosol by the spectroscopic method. By using blight stars as a light source, we can obtain more than 5 profiles of these species in one night. By numerical calculation, we confirm that the possibility of this observation. We have developed a star-tracker, optical system including a telescope and 6-color high-resolution photometer, signal processing electronics and data acquisition system. In the test of performance of the system, we found that the servo-control in the star-tracker was not stable enough to get good quality data. By changing servomotors with digital-controlled motors to improve stability of the star-tracker, we suppose that we can improve the instrument for the balloon experiment. However, **cause of the delay of developing and preparation of the instrument, we cannot make a balloon observation in the period of this grant-aided project research.