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

这项研究的目的是用气球观测平流层中氮氧化物浓度的夜间变化。平流层氮氧化物清单的夜间变化相当显著，因为在硫酸气溶胶存在的情况下，夜间产生的N2O5转化为HNO3的非均相过程被认为在平流层下部的臭氧消耗中起着重要作用。为此，我们正在开发一种用光谱方法观测NO2、NO3、臭氧和气溶胶垂直分布的仪器。利用枯萎星作为光源，我们可以在一夜之间获得这些物种的5个以上的轮廓。通过数值计算，我们证实了这种观测的可能性。我们研制了一台星跟踪器、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。在系统的性能测试中，我们发现星跟踪器的伺服控制不够稳定，无法获得高质量的数据。通过对伺服电机进行数控化改造，提高了星跟踪仪的稳定性，改进了气球实验装置。然而，**由于仪器的开发和准备工作的延误，我们不能在这项赠款资助的项目研究期间进行气球观测。

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.