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)

Abstract

Abstract. 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.

Progress in Spaceborne Passive Microwave Remote Sensing Technology and Its Application

“…HEB混频器和高分辨率数字光谱仪等新技术 [69][70][71] 经成为一个全新的、有潜力的探测要素 [64] 。尽管国际 上已提出多个太赫兹临边探测载荷，但高昂的成本使 得目前还没有新的载荷在轨运行，而 NASA正在研 制小型化的临边探测仪(Continuity-MLS)来接替已 经工作近20年的Aura/MLS [72] 。随着紧凑型、外差 式接收机的发展，使得小卫星搭载小型化、低功耗的 太赫兹临边探测仪成为可能 [73] 。 探 测 器 ( SIW) [74] 和 日 本 的 SMILES的 后 续 型 号 SMILES-2 [75] 。SIW是一个计划安装在一颗小卫星…”

Feasibility analysis of optimal terahertz (THz) bands for passive limb sounding of middle and upper atmospheric wind

“…By measuring the O 3 line and HCl line in the 625 GHz band, the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) observed wind between 30 and 80 km, with the highest precision being 7-9 m s −1 (Baron et al, 2013b). Its successor, SMILES-2, has been proposed to the Japan Aerospace Exploration Agency (JAXA), and wind (30-160 km) is one of the main target parameters (expected precision: 2-5 m s −1 ) (Ochiai et al, 2017;Baron et al, 2020). Another proposed payload is the Stratospheric Inferred Winds (SIW) instrument of the Swedish In-noSat program, which has been selected for launch in recent years (Baron et al, 2018).…”

Measurement of vertical atmospheric density profile from the X-ray Earth occultation of the Crab Nebula with Insight-HXMT

“…However, the measured data of the density in the middle and upper atmosphere are scarce, especially in the upper mesosphere and lower thermosphere (60-200 km), due to the limitation of detection methods (Russell et al, 1999;Baron et al, 2020;Zeitler et al, 2021). With the increasing demand for the density of the Earth's middle and upper atmosphere, various semi-empirical atmosphere models have been developed, such as Jacchia Reference Atmosphere (Jacchia, 1970(Jacchia, , 1977, Drag Temperature Model (DTM) (Berger et al, 1998;Bruinsma et al, 2003) and Mass Spectrometer Incoherent Scatter Radar Extended model (MSIS) (Hedin, 1987;Picone et al, 2002) from Naval Research Laboratory.…”