[A-CG36] Satellite Earth Environment Observation

[ACG36-P09] Diurnal variation of atmospheric CO2 profiles at the Iburi site, Hokkaido forest: Development and field demonstration of high-sensitive multi-wavelnegth IR sensor

*Hiromu Nakagawa¹, Makoto Inoue², Kazuo Watanabe³, Tomoki Takeda⁴, Leo Terada⁵, Mai Shirahata⁵, Norihide Takeyama⁵, Hirofumi Kasahara⁶, Yu Murata⁷, Takumi Miura⁷, Hideo Sagawa⁸, Junichi Kurihara⁹, Takao M. Sato⁹, Hikaru Kitamura¹⁰, Isao Murata¹³, Takeshi Nagayoshi², Masahiko Nagai¹¹, Takumi Hashizume⁶, Yukimi Shimura⁶, Takayoshi Fukuyo¹² (1.Planetary Atmosphere Physics Laboratory, Department of Geophysics, Graduate School of Science, Tohoku University, 2.Akita Prefectural University, 3.Soravision LLC, 4.Japan Space Systems, 5.Genesia Co. Ltd., 6.MUFG Bank, Ltd., 7.I-NET Corp., 8.Kyoto Sangyo University, 9.Hokkaido Information University, 10.Muroran Institute of Technology, 11.Yamaguchi University, 12.ArkEdge Space Inc., 13.Graduate School of Environmental Studies, Tohoku University)

Keywords:GHG, Infrared sensor, spectroscopy, drone, forest

In the "Key and Advanced Technology R&D through Cross Community Collaboration Program (K Program)", we will conduct the development of dedicated technologies for lightweight, compact, and high-sensitive & multi-wavelength infrared sensors, in order to fundamentally strengthen the sensing capability of our country. We also aim to conduct system demonstrations by installing these devices on drones and small satellites. It is important for Japan to have the ability to manufacture and utilize multi-wavelength infrared sensors without depending on other countries. In addition to the security field, the remote sensing technology can be used for new applications and markets in collaboration with the fields of mineral resource exploration, efficient agriculture, forestry, and fisheries, and sustainable activities that do not place an excessive burden on the environment. This paper will introduce the forest environment measurement project led by MUFG bank and Genesia Co. Ltd., which is being promoted within the framework of this project.
In order to examine the diurnal variation of the atmospheric CO2 concentration in broadleaf forest in winter, in-situ measurement of CO2 is performed by drone at the Iburi site, Hokkaido, Japan on 30-31 November, 2023. The drone (DJI Matrice 600) is equipped with the CO2 analyzer (LI-840A) and the CO2 sensor module (Senseair K30). Although drone is limited in altitude compared to airplanes, the drone is low-cost and easy to use, making it possible to observe various locations at high frequency. In addition, compared to observation towers, drone has the advantage of being able to continuously acquire data over a wide area both vertically and horizontally. CO2 vertical profiles are acquired at 5, 10, 50, 100, and 148 m at different local times (11:07 and 14:07 on October 30; 8:40, 9:38, and 13:14 on October 31). Also, the distribution of CO2 concentration in the area of 170-210 m is acquired at 50 m altitude above the surface during 45 minutes from 11:03-11:48 local time. The vertical profiles of CO2 concentration show clear increase by ranging from a few to 5 ppm as the altitude increases from the surface to 148 m at all local times. In addition to vertical profiles, diurnal variation of CO2 profiles is found during early morning to afternoon with a change up to 4 ppm. Also, our result indicates day-to-day changes of CO2 concentration in diurnal cycle up to 5 ppm. In addition, a inhomogeneity of CO2 concentration is found in the horizontal area of 170x210 m of up to 20 ppm. Since the variation and distribution of CO2 concentration are highly dependent on meteorological conditions, simultaneous measurement of wind speed, air temperature, humidity, soil temperature, and vegetation is essential to clarify the contribution of biological respiration and CO2 absorption through plant photosynthesis.