Solar absorption infrared spectroscopic measurements over Mexico City: Methane enhancements

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Auteur principal: ALEJANDRO BEZANILLA
Format: Artículo científico
Langue:en
Publié: Universidad Nacional Autónoma de México 2014
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author ALEJANDRO BEZANILLA
author_facet ALEJANDRO BEZANILLA
contents Solar absorption infrared spectroscopic measurements over Mexico City: Methane enhancements ALEJANDRO BEZANILLA ARNE KRÜGER WOLFGANG STREMME MICHEL GRUTTER Biología methane inverse theory solar absorption FTIR spectroscopy In this work, the experiment for performing solar-absorption infrared measurements from the atmospheric observatory of the Universidad Nacional Aut ó noma de M é xico (UNAM) located at the university campus in Mexico City is described. The Fourier transform infrared (FTIR) spectrometer and solar-tracking system have been operating since June 2010, and from the recorded spectra the total column amounts of several atmospheric gases can be derived. The current study presents the results obtained for methane (CH 4 ), an important pollutant involved in ozone production and a rapidly increasing greenhouse gas. The total column amounts, retrieved with high temporal resolution, present a large dispersion and day-to-day variability. A mean value of 2.88 × 10 19 molecules/cm 2 (1.829 ppm), with a 95% confidence interval between 2.62 and 3.14 × 10 19 molecules/cm 2 , has been obtained for the period from June 2010 to December 2011. No clear annual cycle can be determined from the monthly means due to the large variability in the measurements, suggesting a significant effect of local emissions on the natural background concentrations. Some days with extraordinary enhancements are presented and a simple back trajectory analysis points to a predominant source direction from the northeast of the measurement site. The methane-contaminated air masses passing over the UNAM atmospheric observatory, however, originate presumably not from one but several dispersed sources. A more detailed analysis with modeling of the dynamics of these air masses is required. 2014 artículo científico 0187-6236 https://www.redalyc.org/articulo.oa?id=56531042005 en http://www.redalyc.org/revista.oa?id=565 Atmósfera application/pdf Universidad Nacional Autónoma de México Atmósfera (México) Num.2 Vol.27
format Artículo científico
id redalyc_56531042005
institution Redalyc
language en
publishDate 2014
publisher Universidad Nacional Autónoma de México
spellingShingle Solar absorption infrared spectroscopic measurements over Mexico City: Methane enhancements
ALEJANDRO BEZANILLA
Biología
methane
inverse theory
solar absorption
FTIR spectroscopy
Solar absorption infrared spectroscopic measurements over Mexico City: Methane enhancements ALEJANDRO BEZANILLA ARNE KRÜGER WOLFGANG STREMME MICHEL GRUTTER Biología methane inverse theory solar absorption FTIR spectroscopy In this work, the experiment for performing solar-absorption infrared measurements from the atmospheric observatory of the Universidad Nacional Aut ó noma de M é xico (UNAM) located at the university campus in Mexico City is described. The Fourier transform infrared (FTIR) spectrometer and solar-tracking system have been operating since June 2010, and from the recorded spectra the total column amounts of several atmospheric gases can be derived. The current study presents the results obtained for methane (CH 4 ), an important pollutant involved in ozone production and a rapidly increasing greenhouse gas. The total column amounts, retrieved with high temporal resolution, present a large dispersion and day-to-day variability. A mean value of 2.88 × 10 19 molecules/cm 2 (1.829 ppm), with a 95% confidence interval between 2.62 and 3.14 × 10 19 molecules/cm 2 , has been obtained for the period from June 2010 to December 2011. No clear annual cycle can be determined from the monthly means due to the large variability in the measurements, suggesting a significant effect of local emissions on the natural background concentrations. Some days with extraordinary enhancements are presented and a simple back trajectory analysis points to a predominant source direction from the northeast of the measurement site. The methane-contaminated air masses passing over the UNAM atmospheric observatory, however, originate presumably not from one but several dispersed sources. A more detailed analysis with modeling of the dynamics of these air masses is required. 2014 artículo científico 0187-6236 https://www.redalyc.org/articulo.oa?id=56531042005 en http://www.redalyc.org/revista.oa?id=565 Atmósfera application/pdf Universidad Nacional Autónoma de México Atmósfera (México) Num.2 Vol.27
title Solar absorption infrared spectroscopic measurements over Mexico City: Methane enhancements
topic Biología
methane
inverse theory
solar absorption
FTIR spectroscopy
url https://www.redalyc.org/articulo.oa?id=56531042005