scholarly journals Latitudinal variations of trace gas concentrations in the free troposphere measured by solar absorption spectroscopy during a ship cruise

2000 ◽  
Vol 105 (D1) ◽  
pp. 1337-1349 ◽  
Author(s):  
J. Notholt ◽  
G. C. Toon ◽  
C. P. Rinsland ◽  
N. S. Pougatchev ◽  
N. B. Jones ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Trace Gas ◽  
Free Troposphere ◽  
Solar Absorption ◽  
Latitudinal Variations

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.

scholarly journals Seasonal variations of CO and HCN in the troposphere measured by solar absorption spectroscopy over Poker Flat, Alaska

2005 ◽  
Vol 32 (19) ◽  
pp. n/a-n/a ◽  
Author(s):  
Yasuko J. Kasai ◽  
Akiko Kagawa ◽  
Nicholas Jones ◽  
Akimitsu Fujiwara ◽  
Koji Seki ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Seasonal Variations ◽  
Solar Absorption

scholarly journals Subtropical trace gas profiles determined by ground-based FTIR spectroscopy at Izaña (28° N, 16° W): Five-year record, error analysis, and comparison with 3-D CTMs

2005 ◽  
Vol 5 (1) ◽  
pp. 153-167 ◽  
Author(s):  
M. Schneider ◽  
T. Blumenstock ◽  
M. P. Chipperfield ◽  
F. Hase ◽  
W. Kouker ◽  
...  
Keyword(s):  
Error Analysis ◽  
Three Dimensional ◽  
Trace Gas ◽  
Transport Models ◽  
Solar Absorption ◽  
Annual Cycles ◽  
Mixing Ratios ◽  
Chemical Transport Models ◽  
Tenerife Island ◽  
The Vertical Distribution

Abstract. Within the framework of the NDSC (Network for the Detection of Stratospheric Change) ground-based FTIR solar absorption spectra have been routinely recorded at Izaña Observatory (28° N, 16° W) on Tenerife Island since March 1999. By analyzing the shape of the absorption lines, and their different temperature sensitivities, the vertical distribution of the absorbers can be retrieved. Unique time series of subtropical profiles of O3, HCl, HF, N2O, and CH4 are presented. The effects of both dynamical and chemical annually varying trace gas cycles can be seen in the retrieved profiles. These include enhanced upwelling and photochemistry in summer and a more disturbed atmosphere in winter, which are typical of the subtropical stratosphere. A detailed error analysis has been performed for each profile. The output from two different three-dimensional (3-D) chemical transport models (CTMs), which are forced by ECMWF analyses, are compared to the measured profiles. Both models agree well with the measurements in tracking abrupt variations in the atmospheric structure, e.g. due to tropical streamers, in particular for the lower stratosphere. Simulated and measured profiles also reflect similar dynamical and chemical annual cycles. However, the differences between their mixing ratios clearly exceed the error bars estimated for the measured profiles. Possible reasons for this are discussed.

New perspectives in ultrasensitive trace gas monitoring by cavity-enhanced laser absorption spectroscopy

1999 ◽  
Author(s):  
Alexander A. Kachanov ◽  
Daniele Romanini ◽  
Marc Chenevier ◽  
A. Garnache ◽  
Frederic Stoeckel
Keyword(s):  
Absorption Spectroscopy ◽  
Trace Gas ◽  
Laser Absorption Spectroscopy ◽  
Gas Monitoring ◽  
Laser Absorption

Airborne observations of the 1992 arctic winter stratosphere by FTIR solar absorption spectroscopy

1993 ◽  
Author(s):  
Geoffrey C. Toon ◽  
J. F. Blavier ◽  
J. N. Solario ◽  
J. M. Szeto
Keyword(s):  
Absorption Spectroscopy ◽  
Solar Absorption

scholarly journals First detection of meso-thermospheric Nitric Oxide (NO) by ground-based FTIR solar absorption spectroscopy

2006 ◽  
Vol 33 (3) ◽  
Author(s):  
A. Wiacek ◽  
N. B. Jones ◽  
K. Strong ◽  
J. R. Taylor ◽  
R. L. Mittermeier ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Absorption Spectroscopy ◽  
Solar Absorption

scholarly journals Broadband Cavity Enhanced Differential Optical Absorption Spectroscopy (CE-DOAS) – applicability and corrections

2008 ◽  
Vol 1 (1) ◽  
pp. 481-507 ◽  
Author(s):  
U. Platt ◽  
J. Meinen ◽  
D. Pöhler ◽  
T. Leisner
Keyword(s):  
Absorption Spectroscopy ◽  
Broad Band ◽  
Gas Absorption ◽  
Trace Gas ◽  
Optical Absorption Spectroscopy ◽  
Light Sources ◽  
Light Path ◽  
Gas Concentration ◽  
Mirror Reflectivity ◽  
Gas Measurements

Abstract. Atmospheric trace gas measurements by cavity assisted long-path absorption spectroscopy are an emerging technology. An interesting approach is the combination of CEAS with broad band light sources, the broad-band CEAS (BB-CEAS). BB-CEAS lends itself to the application of the DOAS technique to analyse the derived absorption spectra. While the DOAS approach has enormous advantages in terms of sensitivity and specificity of the measurement, an important implication is the reduction of the light path by the trace gas absorption, since cavity losses due to absorption by gases reduce the quality (Q) of the cavity. In fact, at wavelength, where the quality of the BB-CEAS cavity is dominated by the trace gas absorption (esp. at very high mirror reflectivity), the light path will vary inversely with the trace gas concentration and the strength of the band will become nearly independent of the trace gas concentration c in the cavity, rendering the CEAS Method useless for trace gas measurements. Only in the limiting case where the mirror reflectivity determines Q at all wavelength, the strength of the band as seen by the BB-CEAS instrument becomes proportional to the concentration c. We investigate these relationships in detail and present methods to correct for the cases between the two above extremes, which are of course the important ones in practice.

scholarly journals Formaldehyde total column densities over Mexico City: comparison between multi-axis differential optical absorption spectroscopy and solar-absorption Fourier transform infrared measurements

2021 ◽  
Vol 14 (1) ◽  
pp. 595-613
Author(s):  
Claudia Rivera Cárdenas ◽  
Cesar Guarín ◽  
Wolfgang Stremme ◽  
Martina M. Friedrich ◽  
Alejandro Bezanilla ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Optical Absorption ◽  
Mexico City ◽  
Absorption Spectroscopy ◽  
Fourier Transform Infrared ◽  
Differential Optical Absorption Spectroscopy ◽  
Urban Site ◽  
Optical Absorption Spectroscopy ◽  
Solar Absorption ◽  
Total Column

Abstract. Formaldehyde (HCHO) total column densities over the Mexico City metropolitan area (MCMA) were retrieved using two independent measurement techniques: multi-axis differential optical absorption spectroscopy (MAX-DOAS) and Fourier transform infrared (FTIR) spectroscopy. For the MAX-DOAS measurements, the software QDOAS was used to calculate differential slant column densities (dSCDs) from the measured spectra and subsequently the Mexican MAX-DOAS fit (MMF) retrieval code to convert from dSCDs to vertical column densities (VCDs). The direct solar-absorption spectra measured with FTIR were analyzed using the PROFFIT (PROFile FIT) retrieval code. Typically the MAX-DOAS instrument reports higher VCDs than those measured with FTIR, in part due to differences found in the ground-level sensitivities as revealed from the retrieval diagnostics from both instruments, as the FTIR and the MAX-DOAS information do not refer exactly to the same altitudes of the atmosphere. Three MAX-DOAS datasets using measurements conducted towards the east, west or both sides of the measurement plane were evaluated with respect to the FTIR results. The retrieved MAX-DOAS HCHO VCDs where 6 %, 8 % and 28 % larger than the FTIR measurements which, supported with satellite data, indicates a large horizontal inhomogeneity in the HCHO abundances. The temporal change in the vertical distribution of this pollutant, guided by the evolution of the mixing-layer height, affects the comparison of the two retrievals with different sensitivities (total column averaging kernels). In addition to the reported seasonal and diurnal variability of HCHO columns within the urban site, background data from measurements at a high-altitude station, located only 60 km away, are presented.

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