| 1. |
- Khosrawi, Farahnaz, et al.
(författare)
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Validation of CFC-12 measurements from the Improved Limb Atmospheric Spectrometer (ILAS)
- 2004
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Ingår i: Journal of Geophysical Research. ; 109:D06311
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of CFC-12 were made by the Improved Limb Atmospheric Spectrometer (ILAS) between 57 N and 72 N in the Northern Hemisphere and between 64 S and 89 S in the Southern Hemisphere. ILAS was launched on 17 August 1996 on board the Advanced Earth Observing Satellite (ADEOS). The ILAS validation balloon campaigns were carried out from Kiruna, Sweden (68 N, 21 E), in February and March 1997 and from Fairbanks, Alaska (65 N, 148 W), in April and May 1997. During these validation balloon campaigns, CFC-12 was measured with the in situ instruments ASTRID, BONBON, and SAKURA and the remote sensing spectrometers MIPAS-B, FIRS-2, and MkIV. ILAS version 6.0 CFC-12 profiles obtained at the nearest location to the validation balloon measurement are compared with these validation balloon measurements. The quality of ILAS CFC-12 data processed with the version 6.0 algorithm improved significantly compared to previous versions. Low relative differences between ILAS CFC-12 and the correlative measurements of about 10% were found between 13 and 20 km. The comparison of vertical profiles shows that ILAS CFC-12 data are useful below about 20–22 km inside the vortex and below about 25 km outside the vortex. However, at greater altitudes the relative percentage difference increases very strongly with increasing altitude. Further, correlations of CFC-12 with N2O show a good agreement with the correlative measurements for N2O values of N2O > 150 ppbv. In summary, ILAS CFC-12 data are now suitable for scientific studies in the lower stratosphere.
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| 2. |
- López-Puertas, M., et al.
(författare)
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Non-LTE studies for the analysis of MIPAS/ENVISAT data
- 2002
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Ingår i: Proceedings of SPIE, the International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 4539, s. 381-395
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Tidskriftsartikel (refereegranskat)abstract
- The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is a high-resolution limb sounder on board the European polar platform ENVISAT, scheduled for launch late in 2001. Three main characteristics converge in MIPAS which make it a very useful instrument for non-LTE studies: its wide spectral coverage (4.15-14.6 μm or 680-2275 cm-1); high spectral resolution (0.03 cm-1), and high sensitivity; all of this in addition to its global spatial coverage. In this paper we present an overview of the non-LTE studies that have been carried out in preparation for the analysis of MIPAS data, including the evaluation of non-LTE effects in the operational processing, focussed in the stratosphere, and the retrieval of species that normally emit under non-LTE conditions. The current mission plan for measuring the non-LTE upper atmosphere is described, as well as the general purpose non-LTE retrieval scheme developed for analyzing those measurements.
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