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

• Project/Area Number: 08640555
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Space and upper atmospheric physics
• Research Institution: The University of Tokyo
• Principal Investigator: KITA Kazuyuki The University of Tokyo, Graduate School of Science, Research Associate, 大学院・理学系研究科, 助手 (30221914)
• Co-Investigator(Kenkyū-buntansha): OGAWA Toshihiro The University of Tokyo, Graduate School of Science, Professor, 大学院・理学系研究科, 教授 (70011616) ; SHIBASAKI Kazuo Kokugakuin Univ., Faculty of Literature, Associate Professor, 文学部, 助教授 (00178899) ; IWAGAMI Naomoto The University of Tokyo, Graduate School of Science, Associate Professor, 大学院・理学系研究科, 助教授 (30143374)
• Project Period (FY): 1996 – 1997
• Project Status: Completed (Fiscal Year 1997)
• Budget Amount: ¥2,200,000 (Direct Cost: ¥2,200,000); Fiscal Year 1997: ¥900,000 (Direct Cost: ¥900,000); Fiscal Year 1996: ¥1,300,000 (Direct Cost: ¥1,300,000)
• Keywords: stratosphere / ozone / NOx / global environment / balloon observation

Research Abstract

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.