Retrieval of vertical concentration profiles from OSIRIS UV–visible limb spectra

2002 ◽  
Vol 80 (4) ◽  
pp. 409-434 ◽  
Author(s):  
K Strong ◽  
B M Joseph ◽  
R Dosanjh ◽  
I C McDade ◽  
C A McLinden ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Optimal Estimation ◽  
Gas Absorption ◽  
Forward Model ◽  
Differential Optical Absorption Spectroscopy ◽  
Trace Gas ◽  
Optical Absorption Spectroscopy ◽  
Vertical Profiles ◽  
Uv Visible

The OSIRIS instrument, launched on the Odin satellite in February 2001, includes an optical spectrograph that will record UV–visible spectra of sunlight scattered from the limb over a range of tangent heights. These spectra will be used to retrieve vertical profiles of ozone, NO2, OClO, BrO, NO3, O2, and aerosols, for the investigation of both stratospheric and mesospheric processes, particularly those related to ozone chemistry. In this work, the retrieval of vertical profiles of trace-gas concentrations from OSIRIS limb-radiance spectra is described. A forward model has been developed to simulate these spectra, and it consists of a single-scattering radiative-transfer model with partial spherical geometry, trace-gas absorption, Mie scattering by stratospheric aerosols, a Lambertian surface contribution, and OSIRIS instrument response and noise. Number-density profiles have been retrieved by using optimal estimation (OE) to combine an a priori profile with the information from sets of synthetic ``measurements''. For ozone, OE has been applied both to limb radiances at one or more discrete wavelengths and to effective-column abundances retrieved over a broad spectral range using differential optical absorption spectroscopy (DOAS). The results suggest that, between 15 and 35 km, ozone number densities can be retrieved to 10% accuracy or better on 1 and 2 km grids and to 5% on a 5 km grid. The combined DOAS-OE approach has also been used to retrieve NO2 number densities, yielding 13% accuracy or better for altitudes from 18 to 36 km on a 2 km grid. Differential optical absorption spectroscopy – optimal estimation retrievals of BrO and OClO reproduce the true profiles above 15 km in the noise-free case, but the quality of the retrievals is highly sensitive to noise on the simulated OSIRIS spectra because of the weak absorption of these two gases. The development of inversion methods for the retrieval of trace-gas concentrations from OSIRIS spectra is continuing, and a number of future improvements to the forward model and refinements of the retrieval algorithms are identified. PACS Nos.: 42.68Mj, 94.10Dy

scholarly journals Satellite monitoring of different vegetation types by differential optical absorption spectroscopy (DOAS) in the red spectral range

2007 ◽  
Vol 7 (1) ◽  
pp. 69-79 ◽  
Author(s):  
T. Wagner ◽  
S. Beirle ◽  
T. Deutschmann ◽  
M. Grzegorski ◽  
U. Platt
Keyword(s):  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Spectral Range ◽  
Near Infrared ◽  
Vegetation Type ◽  
Differential Optical Absorption Spectroscopy ◽  
Trace Gas ◽  
Satellite Monitoring ◽  
Optical Absorption Spectroscopy ◽  
Vegetation Types

Abstract. A new method for the satellite remote sensing of different types of vegetation and ocean colour is presented. In contrast to existing algorithms relying on the strong change of the reflectivity in the red and near infrared spectral region, our method analyses weak narrow-band (few nm) reflectance structures (i.e. "fingerprint" structures) of vegetation in the red spectral range. It is based on differential optical absorption spectroscopy (DOAS), which is usually applied for the analysis of atmospheric trace gas absorptions. Since the spectra of atmospheric absorption and vegetation reflectance are simultaneously included in the analysis, the effects of atmospheric absorptions are automatically corrected (in contrast to other algorithms). The inclusion of the vegetation spectra also significantly improves the results of the trace gas retrieval. The global maps of the results illustrate the seasonal cycles of different vegetation types. In addition to the vegetation distribution on land, they also show patterns of biological activity in the oceans. Our results indicate that improved sets of vegetation spectra might lead to more accurate and more specific identification of vegetation type in the future.

Study on Scanning Differential Optical Absorption Spectroscopy for Monitoring Vertical Profiles of Atmospheric Pollutant

2009 ◽  
Vol 29 (2) ◽  
pp. 297-302
Author(s):  
朱燕舞 Zhu Yanwu ◽  
谢品华 Xie Pinhua ◽  
窦科 Dou Ke ◽  
刘世胜 Liu Shisheng ◽  
秦敏 Qin Min ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Differential Optical Absorption Spectroscopy ◽  
Optical Absorption Spectroscopy ◽  
Vertical Profiles ◽  
Atmospheric Pollutant

scholarly journals Satellite monitoring of different vegetation types by differential optical absorption spectroscopy (DOAS) in the red spectral range

2006 ◽  
Vol 6 (4) ◽  
pp. 7945-7958
Author(s):  
T. Wagner ◽  
S. Beirle ◽  
M. Grzegorski ◽  
U. Platt
Keyword(s):  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Spectral Range ◽  
Vegetation Type ◽  
Differential Optical Absorption Spectroscopy ◽  
Trace Gas ◽  
Satellite Monitoring ◽  
Optical Absorption Spectroscopy ◽  
Vegetation Types ◽  
Atmospheric Scattering

Abstract. A new method for the satellite remote sensing of different types of vegetation and ocean colour is presented. In contrast to existing algorithms, our method analyses weak narrow-band reflectance structures (i.e. "fingerprint" structures) of vegetation in the red spectral range. It is based on differential optical absorption spectroscopy (DOAS), which is usually applied for the analysis of atmospheric trace gas absorptions. Since the spectra of atmospheric absorption and vegetation reflectance are simultaneously included in the analysis, the effects of atmospheric scattering and absorption are automatically corrected. The inclusion of the vegetation spectra also significantly improves the results of the trace gas retrieval. The global maps of the fitting coefficients for the vegetation spectra (indicating the fraction of the observed ground scene covered by vegetation) illustrate the seasonal cycle of different vegetation types. In addition to the vegetation distribution on land, they also show patterns of biological activity in the oceans. Our results indicate that improved sets of vegetation spectra might lead to more accurate and more specific identification of vegetation type in the future.

scholarly journals Retrieval interval mapping, a tool to optimize the spectral retrieval range in differential optical absorption spectroscopy

2012 ◽  
Vol 5 (3) ◽  
pp. 4195-4247 ◽  
Author(s):  
L. Vogel ◽  
H. Sihler ◽  
J. Lampel ◽  
T. Wagner ◽  
U. Platt
Keyword(s):  
Optical Absorption ◽  
Wavelength Range ◽  
Absorption Spectroscopy ◽  
Cross Sections ◽  
Trace Gases ◽  
Differential Optical Absorption Spectroscopy ◽  
Trace Gas ◽  
General Nature ◽  
Optical Absorption Spectroscopy ◽  
Cross Correlations

Abstract. Remote sensing via differential optical absorption spectroscopy (DOAS) has become a standard technique to identify and quantify trace gases in the atmosphere. The technique is applied in a variety of configurations, commonly classified into active and passive instruments using artificial and natural light sources, respectively. Platforms range from ground based to satellite instruments and trace-gases are studied in all kinds of different environments. Due to the wide range of measurement conditions, atmospheric compositions and instruments used, a specific challenge of a DOAS retrieval is to optimize the parameters for each specific case and particular trace gas of interest. This becomes especially important when measuring close to the detection limit. A well chosen evaluation wavelength range is crucial to the DOAS technique. It should encompass strong absorption bands of the trace gas of interest in order to maximize the sensitivity of the retrieval, while at the same time minimizing absorption structures of other trace gases and thus potential interferences. Also, instrumental limitations and wavelength depending sources of errors (e.g. insufficient corrections for the Ring effect and cross correlations between trace gas cross sections) need to be taken into account. Most often, not all of these requirements can be fulfilled simultaneously and a compromise needs to be found depending on the conditions at hand. Although for many trace gases the overall dependence of common DOAS retrieval on the evaluation wavelength interval is known, a systematic approach to find the optimal retrieval wavelength range and qualitative assessment is missing. Here we present a novel tool to determine the optimal evaluation wavelength range. It is based on mapping retrieved values in the retrieval wavelength space and thus visualize the consequence of different choices of retrieval spectral ranges, e.g. caused by slightly erroneous absorption cross sections, cross correlations and instrumental features. The technique is demonstrated using the examples of a theoretical study of BrO retrievals for stratospheric BrO measurements and for BrO measurements in volcanic plumes. However, due to the general nature of the tool, it is applicable to any type (active or passive) of DOAS retrieval.

Differential optical absorption spectroscopy instrument for stratospheric balloonborne trace-gas studies

2000 ◽  
Vol 39 (15) ◽  
pp. 2377 ◽  
Author(s):  
Frieder Ferlemann ◽  
Nadine Bauer ◽  
Richard Fitzenberger ◽  
Hartwig Harder ◽  
Hartmut Osterkamp ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Differential Optical Absorption Spectroscopy ◽  
Trace Gas ◽  
Optical Absorption Spectroscopy

scholarly journals Inter-comparison of stratospheric O<sub>3</sub> and NO<sub>2</sub> abundances retrieved from balloon borne direct sun observations and Envisat/SCIAMACHY limb measurements

2005 ◽  
Vol 5 (5) ◽  
pp. 10747-10797
Author(s):  
A. Butz ◽  
H. Bösch ◽  
C. Camy-Peyret ◽  
M. Chipperfield ◽  
M. Dorf ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Optical Absorption ◽  
Ultra Violet ◽  
Trace Gas ◽  
Optical Absorption Spectroscopy ◽  
Line Of Sight ◽  
Vertical Profiles ◽  
Altitude Range ◽  
Solar Occultation ◽  
Uv Visible

Abstract. Stratospheric O3 and NO2 abundances measured by different remote sensing instruments are inter-compared: (1) Line-of-sight absorptions and vertical profiles inferred from solar spectra in the ultra-violet (UV), visible and infrared (IR) wavelength ranges measured by the LPMA/DOAS (Limb Profile Monitor of the Atmosphere/Differential Optical Absorption Spectroscopy) balloon payload during balloon ascent/descent and solar occultation are examined with respect to internal consistency. (2) The balloon borne stratospheric profiles of O3 and NO2 are compared to collocated space-borne skylight limb observations of the Envisat/SCIAMACHY satellite instrument. The trace gas profiles are retrieved from SCIAMACHY spectra using different algorithms developed at the Universities of Bremen and Heidelberg and at the Harvard-Smithsonian Center for Astrophysics. A comparison scheme is used that accounts for the spatial and temporal mismatch as well as differing photochemical conditions between the balloon and satellite borne measurements. It is found that the balloon borne measurements internally agree to within ±10% and ±20% for O3 and NO2, respectively, whereas the agreement with the satellite is ±20% for both gases in the 20 km to 30 km altitude range and in general worse below 20 km.

scholarly journals Inter-comparison of stratospheric O<sub>3</sub> and NO<sub>2</sub> abundances retrieved from balloon borne direct sun observations and Envisat/SCIAMACHY limb measurements

2006 ◽  
Vol 6 (5) ◽  
pp. 1293-1314 ◽  
Author(s):  
A. Butz ◽  
H. Bösch ◽  
C. Camy-Peyret ◽  
M. Chipperfield ◽  
M. Dorf ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Optical Absorption ◽  
Ultra Violet ◽  
Trace Gas ◽  
Optical Absorption Spectroscopy ◽  
Line Of Sight ◽  
Vertical Profiles ◽  
Altitude Range ◽  
Solar Occultation ◽  
Uv Visible

Abstract. Stratospheric O3 and NO2 abundances measured by different remote sensing instruments are inter-compared: (1) Line-of-sight absorptions and vertical profiles inferred from solar spectra in the ultra-violet (UV), visible and infrared (IR) wavelength ranges measured by the LPMA/DOAS (Limb Profile Monitor of the Atmosphere/Differential Optical Absorption Spectroscopy) balloon payload during balloon ascent/descent and solar occultation are examined with respect to internal consistency. (2) The balloon borne stratospheric profiles of O3 and NO2 are compared to collocated space-borne skylight limb observations of the Envisat/SCIAMACHY satellite instrument. The trace gas profiles are retrieved from SCIAMACHY spectra using different algorithms developed at the Universities of Bremen and Heidelberg and at the Harvard-Smithsonian Center for Astrophysics. A comparison scheme is used that accounts for the spatial and temporal mismatch as well as differing photochemical conditions between the balloon and satellite borne measurements. It is found that the balloon borne measurements internally agree to within ±10% and ±20% for O3 and NO2, respectively, whereas the agreement with the satellite is ±20% for both gases in the 20 km to 30 km altitude range and in general worse below 20 km.

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