[M-SD35] Future Missions of Satellite Earth Observation

[MSD35-06] TeraHertz ice cloud/water vapor micro satellite mission

*Nawo Eguchi¹, Hirohiko Masunaga², Yasuko Kasai³, Ryoichi Imasu⁴, Keiji Imaoka⁵, Hironobu Iwabuchi⁶, Keiichi Ohara², Junko Suzuki⁷, Tatsuya Seiki⁸, Toshiya Hanada⁹, Tadahiro Hayasaka⁶, Kei Yoshimura¹⁰ (1.Research Institute for Applied Mechanics, Kyushu Univ., 2.Institute for Space-Earth Environmental Research, Nagoya Univ., 3.National Institute of Information and Communications Technology, 4.Atmosphere and Ocean Research Institute, Univ. of Tokyo, 5.Organization for Research Initiatives, Yamaguchi Univ., 6.Center for Atmospheric and Oceanic Studies, Tohoku Univ., 7.Japan Agency for Marine-Earth Science and Technology, Research Institute for Global Change, Center for Coupled Ocean-Atmosphere Research, 8.Japan Agency for Marine-Earth Science and Technology, Research Institute for Global Change, Research Center for Environmental Modeling and Application, 9.Faculty of Engineering, Kyushu Univ., 10.Institute of Industrial Science, Univ. of Tokyo)

Keywords:TeraHertz band, micro satellite, ice clouds

Ice clouds greatly contribute to climate through radiation processes and the amount of water vapor entering the stratosphere, and their high spatiotemporal variability makes global observations essential. However, due to the limitations of conventional satellite observation instruments and wavelengths, the macroscopic and microscopic dynamics have not yet been clarified.
The purpose of this mission is to clarify the details of microphysical processes in ice clouds in the middle and upper troposphere (MT/UT) using wavelengths in the TeraHertz (THz) band, which have been technically and scientifically unexplored. The parameters derived in this mission are the presence or absence of ice clouds at MT/UT, existence altitude, particle size and particle type (TBD) inside the cloud. One of the characteristics of the THz band is that it is sensitive to cloud droplets with a particle size of several tens to several hundred μm at an altitude of 7 km or higher (using the water vapor saturation bands), and it is possible to observe even inside the clouds. The obtained data will not only allow us to understand more detailed microphysical processes in clouds, but also to understand the life cycle of clouds via the water vapor flux inside and outside the clouds by observing them together with water vapor around the clouds. becomes possible.
On the other hand, the development of technology for THz-band earth atmospheric observation will not only advance and apply instrumentation technology to the unexplored wavelength band between high and low frequencies, but also integrate it with existing instruments. It is expected to contribute to the construction of a more efficient satellite observation system.