Tangent height accuracy of superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on International Space Station (ISS)

Ochiai, Satoshi; Nishibori, Toshiyuki; Kikuchi, K.; Mizobuchi, S.; Manabe, Tetsuya; Mitsuda, Chihiro; Baron, Philippe; Ueno, S.

doi:10.1109/igarss.2012.6350824

Cited by 4 publications

(3 citation statements)

References 6 publications

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“…Bias in the measured tangent height was retrieved in the L2r retrieval analysis. Random uncertainty was due to measurement errors of the ISS attitude, and was estimated to be about 0.001 • (Ochiai et al, 2012b). It corresponds to 40 m in the tangent height and 0.5 % in the spectrum brightness temperature, which is much smaller than the total random error discussed later.…”

Section: T O Sato Et Al: Error Analysis and Diurnal Variation Of Smentioning

confidence: 97%

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

et al. 2012

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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-sunsynchronous 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 mid-

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Section: T O Sato Et Al: Error Analysis and Diurnal Variation Of Smentioning

confidence: 97%

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

et al. 2012

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“…We also expect better retrievals thanks to improvements of the calibrated radiances and spectrometer frequencies spectra (Ochiai et al, 2012c;Mizobuchi et al, 2012a), and of the inversion methodology (e.g. joint inversion of different lines and bands).…”

Section: P Baron Et Al: Smiles Winds 6061 5 Conclusionmentioning

confidence: 99%

Observation of horizontal winds in the middle-atmosphere between 30° S and 55° N during the northern winter 2009–2010

et al. 2013

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Abstract. Although the links between stratospheric dynamics, climate and weather have been demonstrated, direct observations of stratospheric winds are lacking, in particular at altitudes above 30 km. We report observations of winds between 8 and 0.01 hPa (~35–80 km) from October 2009 to April 2010 by the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the International Space Station. The altitude range covers the region between 35–60 km where previous space-borne wind instruments show a lack of sensitivity. Both zonal and meridional wind components were obtained, though not simultaneously, in the latitude range from 30° S to 55° N and with a single profile precision of 7–9 m s–1 between 8 and 0.6 hPa and better than 20 m s–1 at altitudes above. The vertical resolution is 5–7 km except in the upper part of the retrieval range (10 km at 0.01 hPa). In the region between 1–0.05 hPa, an absolute value of the mean difference < 2 m s–1 is found between SMILES profiles retrieved from different spectroscopic lines and instrumental settings. Good agreement (absolute value of the mean difference of ~2 m s–1) is also found with the European Centre for Medium-Range Weather Forecasts (ECMWF) analysis in most of the stratosphere except for the zonal winds over the equator (difference > 5 m s−1). In the mesosphere, SMILES and ECMWF zonal winds exhibit large differences (> 20 m s–1), especially in the tropics. We illustrate our results by showing daily and monthly zonal wind variations, namely the semi-annual oscillation in the tropics and reversals of the flow direction between 50–55° N during sudden stratospheric warmings. The daily comparison with ECMWF winds reveals that in the beginning of February, a significantly stronger zonal westward flow is measured in the tropics at 2 hPa compared to the flow computed in the analysis (difference of ~20 m s–1). The results show that the comparison between SMILES and ECMWF winds is not only relevant for the quality assessment of the new SMILES winds, but it also provides insights on the quality of the ECMWF winds themselves. Although the instrument was not specifically designed for measuring winds, the results demonstrate that space-borne sub-mm wave radiometers have the potential to provide good quality data for improving the stratospheric winds in atmospheric models.

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“…In coming work, SMILES mesospheric winds will be validated using ground-based radar observations. We also expect better retrievals thanks to improvements of the calibrated radiances and spectrometer frequencies spectra (Ochiai et al, 2012c;Mizobuchi et al, 2012a), and of the inversion methodology (e.g. joint inversion of different lines and bands).…”

Section: P Baron Et Al: Smiles Winds 6061 5 Conclusionmentioning

confidence: 99%

Observation of horizontal winds in the middle-atmosphere between 30° S and 55° N during the northern winter 2009–2010

Baron¹,

Murtagh²,

Urban³

et al. 2012

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Although the links between stratospheric dynamics, climate and weather have been demonstrated, direct observations of stratospheric winds are lacking. We report observations of winds between 8 and 0.01 hPa (~35–80 km) from October 2009 to April 2010 by the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the International Space Station. The altitude range covers the region between 35–60 km where previous space-borne wind instruments show a lack of sensitivity. Both zonal and meridional wind components were obtained, though not simultaneously, in the latitude range from 30° S to 55° N and with a single profile precision of 7–9 m s⁻¹ between 8 and 0.6 hPa and better than 20 m s⁻¹ at altitudes above. The vertical resolution is 5–7 km except in the upper part of the retrieval range (10 km at 0.01 hPa). In the region between 1–0.05 hPa, a mean difference <2 m s⁻¹ is found between SMILES profiles retrieved from different spectroscopic lines and instrumental settings. Good agreement (mean difference of ~2 m s⁻¹) is also found with the European Centre for Medium-Range Weather Forecasts (ECMWF) analysis in most of the stratosphere except for the zonal winds over the equator (mean difference of 5–10 m s⁻¹). In the mesosphere, SMILES and ECMWF zonal winds exhibit large differences (> 20 m s⁻¹), especially in the tropics. We illustrate our results by showing daily and monthly zonal wind variations, namely the semi-annual oscillation in the tropics and reversals of the flow direction between 50° N–55° N during sudden stratospheric warmings in the stratosphere. The daily comparison with ECMWF winds reveals that in the beginning of February, a significantly stronger zonal westward flow is measured in the tropics at 2 hPa compared to the flow computed in the analysis (difference of ~20 m s⁻¹). The results show that the comparison between SMILES and ECMWF winds is not only relevant for the quality assessment of the new SMILES winds but it also provides insights on the quality of the ECMWF winds themselves. Although the instrument was not specifically designed for measuring winds, the results demonstrate that space-borne sub-mm wave radiometers have the potential to provide good quality data for improving the stratospheric winds in atmospheric models

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Tangent height accuracy of superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on International Space Station (ISS)

Cited by 4 publications

References 6 publications

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

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

Observation of horizontal winds in the middle-atmosphere between 30° S and 55° N during the northern winter 2009–2010

Observation of horizontal winds in the middle-atmosphere between 30° S and 55° N during the northern winter 2009–2010

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