THz limb sounder (TLS) for lower thermospheric wind, oxygen density, and temperature

Wu, Dong L.; Yee, Jeng‐Hwa; Schlecht, Erich; Mehdi, Imran; Siles, José V.; Drouin, Brian J.

doi:10.1002/2015ja022314

Cited by 29 publications

(19 citation statements)

References 52 publications

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“…There are two bright thermal emission lines of atomic oxygen at 2.06 and 4.7 THz in the thermosphere (Wu et al 2016). This atom controls the radiative equilibrium and is important for the chemistry.…”

Section: Introductionmentioning

confidence: 99%

“…Small satellite concepts have been proposed in Sweden for measuring wind, temperature, and molecules in the stratosphere with a 650 GHz Schottky receiver cooled to 100 K (Murtagh 2016), and in the US for lower thermospheric observations with a 2.06 THz receiver (Wu et al 2016). If realized, these missions will be the first SMM missions specifically designed for wind…”

Section: Introductionmentioning

confidence: 99%

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SMILES-2 Mission for Temperature, Wind, and Composition in the Whole Atmosphere

Ochiai

Baron

Nishibori

et al. 2017

SOLA

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The Superconducting Submillimeter-Wave Limb-Emission Sounder 2 (SMILES-2) is a satellite mission that will be proposed to the Japan Aerospace Exploration Agency (JAXA) for a launch after 2023. It will scan the atmospheric limb from the lower stratosphere to the lower thermosphere for retrieving the profiles of temperature between 15 and 160 km, horizontal wind vector (30− 160 km), ground state atomic oxygen (90−160 km), and dynamical tracers and ozone-chemistry related species (15−110 km). SMILES-2 is designed to fit the JAXA small satellite and will be equipped with two antennas, three GHz-channel receivers, and one THz receiver. Each receiver has a superconducting device on the front end cooled by a mechanical cryocooler, which is an established technology. Highly sensitive limb observation owing to the superconducting technology has great advantages of satisfactorily measuring all the altitude profiles in a short time of less than 1 min, and of retrieving the main products with sufficient precision on a single profile. Hence, a wind vector profile can be obtained with a precision better than 10 m s −1 with a vertical resolution of 3 km below 100 km and 5 km above 100 km.(Citation: Ochiai, S., P. Baron, T. Nishibori, Y. Iri majiri, Y. Uzawa, T. Manabe, H. Maezawa, A. Mizuno, T. Naga hama, H. Sagawa, M. Suzuki, and M. Shiotani, 2017: SMILES-2 mission for temperature, wind, and composition in the whole atmosphere. SOLA, 13A, 13−18,

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

SMILES-2 Mission for Temperature, Wind, and Composition in the Whole Atmosphere

Ochiai

Baron

Nishibori

et al. 2017

SOLA

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“…Two smaller instruments are under consideration for satellite launch as early as 2020-2022. Wu et al (2016) propose a small instrument for measuring the atomic oxygen line at 2.06 THz in order to retrieve its abundance as well as temperature and wind in the lower thermosphere. However this instrument cannot provide stratospheric and lower mesospheric information.…”

Section: Introductionmentioning

confidence: 99%

Simulation study for the Stratospheric Inferred Winds (SIW) sub-millimeter limb sounder

et al. 2018

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Abstract. Stratospheric Inferred Winds (SIW) is a Swedish mini sub-millimeter limb sounder selected for the 2nd InnoSat platform, with launch planned for around 2022. It is intended to fill the altitude gap between 30 and 70 km in atmospheric wind measurements and also aims at pursuing the limb observations of temperature and key atmospheric constituents between 10 and 90 km when current satellite missions will probably come to an end. Line-of-sight winds are retrieved from the Doppler shift of molecular emission lines introduced by the wind field. Observations will be performed with two antennas pointing toward the limb in perpendicular directions in order to reconstruct the 2-D horizontal wind vector. Each antenna has a vertical field of view (FOV) of 5 km. The chosen spectral band, near 655 GHz, contains a dense group of strong O 3 lines suitable for exploiting the small amount of wind information in stratospheric spectra. Using both sidebands of the heterodyne receiver, a large number of chemical species will be measured, including O 3 isotopologues, H 2 O, HDO, HCl, ClO, N 2 O, HNO 3 , NO, NO 2 , HCN, CH 3 CN and HO 2 . This paper presents a simulation study that assesses measurement performance. The line-of-sight winds are retrieved between 30 and 90 km with the best sensitivity between 35 and 70 km, where the precision (1σ ) is 5-10 m s −1 for a single scan. Similar performance can be obtained during day and night conditions except in the lower mesosphere, where the photo-dissociation of O 3 in daytime reduces the sensitivity by 50 % near 70 km. Profiles of O 3 , H 2 O and temperature are retrieved with high precision up to 50 km (< 1 %, < 2 %, 1 K, respectively). Systematic errors due to uncertainties in spectroscopic parameters, in the radiometer sideband ratio and in the radiance calibration process are investigated. A large wind retrieval bias of 10-30 m s −1 between 30 and 40 km could be induced by the air-broadening parameter uncertainties of O 3 lines. This highlights the need for good knowledge of these parameters and for studying methods to mitigate the retrieval bias.

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“…Currently, several new instruments are being developed. THz limb sounder (TLS) proposed in the US aims to 15 measure lower thermospheric wind, oxygen density, and temperature (Wu et al, 2016). However, it cannot obtain the information in the stratosphere and lower mesosphere.…”

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confidence: 99%

Performance Evaluation of THz Atmospheric Limb Sounder (TALIS) of China

Wang¹,

Wang²,

Duan³

2019

Preprint

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THz Atmospheric Limb Sounder (TALIS) is a microwave limb sounder being developed for atmospheric high precision observation by the National Space Science Center, Chinese Academy of Sciences (NSSC, CAS). It is designed to measure the temperature and chemical species such as O 3 , HCl, ClO, N 2 O, NO, NO 2 , HOCl, H 2 O, HNO 3 , HCN, CO, SO 2 , 10 BrO, HO 2 , H 2 CO, CH 3 Cl, CH 3 OH, and CH 3 CN with high vertical resolution from surface to about 100 km to improve our comprehension of atmospheric chemistry and dynamics, and to monitor the man-made pollution in the atmosphere. Four heterodyne radiometers including several FFT spectrometers of 2 GHz bandwidth with 2 MHz resolution are employed to obtain the atmospheric thermal emission in broad spectral regions centred near 118, 190, 240, and 643 GHz. A theoretical simulation is performed to estimate the retrieval precision of the main targets. Single scan measurement and averaged 15 measurement are considered in simulation, respectively. Temperature profile can be obtained with the precision of < 2K for a single scan from 15 to 85 km by using 118 GHz radiometer, and the 240 and 643 GHz radiometer can provide temperature information in the upper troposphere. Chemical species such as H 2 O, O 3 , HCl, N 2 O, and HNO 3 show high single scan retrieval precision of 1-50% at most altitudes. The other species should be retrieved by using averaged measurements because of the weak intensity or low abundance. 20 IntroductionHigh precision observation of the Earth's atmosphere is essential to the numerical weather prediction and climate change studies. The satellite can provide global coverage atmospheric monitoring in a short time. Instruments such as nadir microwave sounder and infrared sounder have been applied to measure the atmospheric temperature and humidity but with the poor vertical resolution and altitude range (Swadley et al., 2008). Terahertz limb sounder can not only provide the 25 temperature profile with better vertical resolution but gather information on chemical composition in a wide altitude range and independent of the day-night cycle. Microwave limb sounding is a particularly useful technique in detecting stratospheric and mesospheric temperature and chemistry, and also has large potential for global wind measurement in the middle and upper atmosphere (Ochiai et al., 2017). Bands selectionThe spectral bands of TALIS are selected with the following criterions: (1) maximizing the number of species which will exert a strong influence on atmospheric chemistry and dynamics, (2) necessary space between the passband, (3) trade-off between realizable bandwidth and resolution. TALIS covers most spectral bands of EOS MLS and extends them. The broader bandwidth, finer resolution, and lower noise of TALIS can provide higher retrieval precision and effective altitude 15 range compared with EOS MLS. More chemical species can be measured by TALIS, such as NO 2 , NO, H 2 CO, and SO 2 (normal concentration).The 118 GHz radiometer, covering the strong O 2 line at 118.75 GH...

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THz limb sounder (TLS) for lower thermospheric wind, oxygen density, and temperature

Cited by 29 publications

References 52 publications

SMILES-2 Mission for Temperature, Wind, and Composition in the Whole Atmosphere

SMILES-2 Mission for Temperature, Wind, and Composition in the Whole Atmosphere

Simulation study for the Stratospheric Inferred Winds (SIW) sub-millimeter limb sounder

Performance Evaluation of THz Atmospheric Limb Sounder (TALIS) of China

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