University of Oulu

Baron, P., Ochiai, S., Dupuy, E., Larsson, R., Liu, H., Manago, N., Murtagh, D., Oyama, S., Sagawa, H., Saito, A., Sakazaki, T., Shiotani, M., and Suzuki, M.: Potential for the measurement of mesosphere and lower thermosphere (MLT) wind, temperature, density and geomagnetic field with Superconducting Submillimeter-Wave Limb-Emission Sounder 2 (SMILES-2), Atmos. Meas. Tech., 13, 219–237,, 2020

Potential for the measurement of mesosphere and lower thermosphere (MLT) wind, temperature, density and geomagnetic field with Superconducting Submillimeter-Wave Limb-Emission Sounder 2 (SMILES-2)

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Author: Baron, Philippe1; Ochiai, Satoshi1; Dupuy, Eric2;
Organizations: 1National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, Japan
2Center for Global Environmental Research, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506, Japan
3Planets, Max Planck Institute for Solar System Research, Göttingen, Lower Saxony, Germany
4Department of Earth and Planetary Science, Kyushu University, Fukuoka 812-8581, Japan
5Center for Environmental Remote Sensing, Chiba University, Chiba-shi, Japan
6Department of Space, Earth and Environment, Chalmers University of Technology, 41296 Gothenburg, Sweden
7Institute for Space-Earth Environmental Research, Nagoya University, Nagoya Aichi 464-8601, Japan
8Ionosphere Research Unit, University of Oulu, Oulu, Finland
9National Institute of Polar Research, Tachikawa-shi, Tokyo 190-8518, Japan
10Division of Science, Kyoto Sangyo University, Kyoto 603-8555, Japan
11Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
12Research Institute for Sustainable Humanosphere, Kyoto University, Kyoto 611-0011, Japan
13Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 252-5210, Japan
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 4.8 MB)
Persistent link:
Language: English
Published: Copernicus Publications, 2020
Publish Date: 2020-04-03


Submillimeter-Wave Limb-Emission Sounder 2 (SMILES-2) is a satellite mission proposed in Japan to probe the middle and upper atmosphere (20–160 km). The main instrument is composed of 4 K cooled radiometers operating near 0.7 and 2 THz. It could measure the diurnal changes of the horizontal wind above 30 km, temperature above 20 km, ground-state atomic oxygen above 90 km and atmospheric density near the mesopause, as well as abundance of about 15 chemical species. In this study we have conducted simulations to assess the wind, temperature and density retrieval performance in the mesosphere and lower thermosphere (60–110 km) using the radiometer at 760 GHz. It contains lines of water vapor (H₂O), molecular oxygen (O₂) and nitric oxide (NO) that are the strongest signals measured with SMILES-2 at these altitudes. The Zeeman effect on the O₂ line due to the geomagnetic field (B) is considered; otherwise, the retrieval errors would be underestimated by a factor of 2 above 90 km. The optimal configuration for the radiometer’s polarization is found to be vertical linear. Considering a retrieval vertical resolution of 2.5 km, the line-of-sight wind is retrieved with a precision of 2–5 m s−1 up to 90 km and 30 m s−1 at 110 km. Temperature and atmospheric density are retrieved with a precision better than 5 K and 7 % up to 90 km (30 K and 20 % at 110 km). Errors induced by uncertainties on the vector B are mitigated by retrieving it. The retrieval of B is described as a side-product of the mission. At high latitudes, precisions of 30–100 nT on the vertical component and 100–300 nT on the horizontal one could be obtained at 85 and 105 km (vertical resolution of 20 km). SMILES-2 could therefore provide the first measurements of B close to the electrojets’ altitude, and the precision is enough to measure variations induced by solar storms in the auroral regions.

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Series: Atmospheric measurement techniques
ISSN: 1867-1381
ISSN-E: 1867-8548
ISSN-L: 1867-1381
Volume: 13
Issue: 1
Pages: 219 - 237
DOI: 10.5194/amt-13-219-2020
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: SMILES-2 studies are supported by the strategic development research fund from the Institute of Space and Astronautical Science (ISAS)/JAXA. Huixin Liu acknowledges support by JSPS KAKENHI (grants no. 18H01270, 18H04446 and 17KK0095).
Copyright information: © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License.