A submillimeter-wave sensor for trace gas studies in the middle atmosphere

Strato-mesospheric ClO observations by SMILES: error analysis and diurnal variation

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-5-4667-2012 ◽

2012 ◽

Vol 5 (4) ◽

pp. 4667-4710 ◽

Cited By ~ 1

Author(s):

T. O. Sato ◽

H. Sagawa ◽

D. Kreyling ◽

T. Manabe ◽

S. Ochiai ◽

...

Keyword(s):

Error Analysis ◽

Diurnal Variation ◽

Middle Atmosphere ◽

Total Error ◽

Space Station ◽

Submillimeter Wave ◽

Radiative Transfer Model ◽

Transfer Model ◽

Instrument Function ◽

Key Species

Abstract. Chlorine monoxide (ClO) is the key species for anthropogenic ozone loss in the middle atmosphere. We observed the ClO diurnal variation using the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the International Space Station which has a non sun-synchronous orbit. This is the first global observation of the ClO diurnal variation from the stratosphere up to the mesosphere. The SMILES observation reproduced the diurnal variation of stratospheric ClO, an enhancement during a daytime, as observed by the Microwave Limb Sounder on the Upper Atmosphere Research Satellite (UARS/MLS). Mesospheric ClO has shown a different diurnal behavior with an enhancement during nighttime. The ClO enhancement was found at a pressure of 0.02 hPa (about 70 km) with an amplitude of about 100 pptv and reached up to 0.01 hPa (80 km) in the zonal mean of 50° N–65° N in January–February 2010. The observation of mesospheric ClO was possible due to the 10–20 times better signal-to-noise ratio of the spectra than those of past microwave/submillimeter-wave limb-emission sounders. We performed a quantitative error analysis for the strato- and mesospheric ClO of the Level-2 research (L2r) product version 2.1.5 taking into account all possible error contributions; i.e. errors due to spectrum noise, smoothing and uncertainties in the radiative transfer model and instrument function. The SMILES L2r v2.1.5 ClO data are useful over the range 0.01 and 100 hPa with a total error of 10–30 pptv (about 10%) with averaging of 100 profiles. The vertical resolution is 3–5 km and 5–8 km for the stratosphere and mesosphere, respectively. The performance of the SMILES observation opens the new opportunity to investigate ClO up to the mesopause.

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Atmospheric and ionospheric response to trace gas perturbations through the ice age to the next century in the middle atmosphere. Part II — ionization

Journal of Atmospheric and Solar-Terrestrial Physics ◽

10.1016/s1364-6826(96)00092-2 ◽

1997 ◽

Vol 59 (11) ◽

pp. 1261-1275 ◽

Cited By ~ 6

Author(s):

G. Beig ◽

A.P. Mitra

Keyword(s):

Middle Atmosphere ◽

Ice Age ◽

Trace Gas ◽

Ionospheric Response

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The Level 2 research product algorithms for the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES)

Atmospheric Measurement Techniques ◽

10.5194/amt-4-2105-2011 ◽

2011 ◽

Vol 4 (10) ◽

pp. 2105-2124 ◽

Cited By ~ 42

Author(s):

P. Baron ◽

J. Urban ◽

H. Sagawa ◽

J. Möller ◽

D. P. Murtagh ◽

...

Keyword(s):

Error Analysis ◽

Pressure Profile ◽

Calibration Procedure ◽

Submillimeter Wave ◽

Trace Gas ◽

Line Center ◽

Large Temperature ◽

High Signal ◽

Retrieval Error ◽

Level 2

Abstract. This paper describes the algorithms of the level-2 research (L2r) processing chain developed for the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES). The chain has been developed in parallel to the operational chain for conducting researches on calibration and retrieval algorithms. L2r chain products are available to the scientific community. The objective of version 2 is the retrieval of the vertical distribution of trace gases in the altitude range of 18–90 km. A theoretical error analysis is conducted to estimate the retrieval feasibility of key parameters of the processing: line-of-sight elevation tangent altitudes (or angles), temperature and ozone profiles. While pointing information is often retrieved from molecular oxygen lines, there is no oxygen line in the SMILES spectra, so the strong ozone line at 625.371 GHz has been chosen. The pointing parameters and the ozone profiles are retrieved from the line wings which are measured with high signal to noise ratio, whereas the temperature profile is retrieved from the optically thick line center. The main systematic component of the retrieval error was found to be the neglect of the non-linearity of the radiometric gain in the calibration procedure. This causes a temperature retrieval error of 5–10 K. Because of these large temperature errors, it is not possible to construct a reliable hydrostatic pressure profile. However, as a consequence of the retrieval of pointing parameters, pressure induced errors are significantly reduced if the retrieved trace gas profiles are represented on pressure levels instead of geometric altitude levels. Further, various setups of trace gas retrievals have been tested. The error analysis for the retrieved HOCl profile demonstrates that best results for inverting weak lines can be obtained by using narrow spectral windows.

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Strato-mesospheric ClO observations by SMILES: error analysis and diurnal variation

Atmospheric Measurement Techniques ◽

10.5194/amt-5-2809-2012 ◽

2012 ◽

Vol 5 (11) ◽

pp. 2809-2825 ◽

Cited By ~ 19

Author(s):

T. O. Sato ◽

H. Sagawa ◽

D. Kreyling ◽

T. Manabe ◽

S. Ochiai ◽

...

Keyword(s):

Error Analysis ◽

Diurnal Variation ◽

Middle Atmosphere ◽

Total Error ◽

Space Station ◽

Submillimeter Wave ◽

Radiative Transfer Model ◽

Transfer Model ◽

Key Species ◽

Synchronous Orbit

Abstract. Chlorine monoxide (ClO) is the key species for anthropogenic ozone losses in the middle atmosphere. We observed ClO diurnal variations using the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the International Space Station, which has a non-sun-synchronous orbit. This includes the first global observations of the ClO diurnal variation from the stratosphere up to the mesosphere. The observation of mesospheric ClO was possible due to 10–20 times better signal-to-noise (S/N) ratio of the spectra than those of past or ongoing microwave/submillimeter-wave limb-emission sounders. We performed a quantitative error analysis for the strato- and mesospheric ClO from the Level-2 research (L2r) product version 2.1.5 taking into account all possible contributions of errors, i.e. errors due to spectrum noise, smoothing, and uncertainties in radiative transfer model and instrument functions. The SMILES L2r v2.1.5 ClO data are useful over the range from 0.01 and 100 hPa with a total error estimate of 10–30 pptv (about 10%) with averaging 100 profiles. The SMILES ClO vertical resolution is 3–5 km and 5–8 km for the stratosphere and mesosphere, respectively. The SMILES observations reproduced the diurnal variation of stratospheric ClO, with peak values at midday, observed previously by the Microwave Limb Sounder on the Upper Atmosphere Research Satellite (UARS/MLS). Mesospheric ClO demonstrated an opposite diurnal behavior, with nighttime values being larger than daytime values. A ClO enhancement of about 100 pptv was observed at 0.02 to 0.01 hPa (about 70–80 km) for 50° N–65° N from January–February 2010. The performance of SMILES ClO observations opens up new opportunities to investigate ClO up to the mesopause.

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