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

Rivera Cárdenas, Claudia; Guarín, Cesar; Stremme, Wolfgang; Friedrich, Martina M.; Bezanilla, Alejandro; Rivera Ramos, Diana; Mendoza-Rodríguez, Cristina A.; Grutter, Michel; Blumenstock, Thomas ORCID iD icon 1; Hase, Frank 1
1 Institut für Meteorologie und Klimaforschung (IMK), Karlsruher Institut für Technologie (KIT)

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. ... mehr

Verlagsausgabe §
DOI: 10.5445/IR/1000134581
Veröffentlicht am 30.06.2021
DOI: 10.5194/amt-14-595-2021
Zitationen: 2
Web of Science
Zitationen: 1
Zitationen: 2
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Meteorologie und Klimaforschung – Atmosphärische Spurenstoffe und Fernerkundung (IMK-ASF)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2021
Sprache Englisch
Identifikator ISSN: 1867-8548
KITopen-ID: 1000134581
HGF-Programm 12.11.13 (POF IV, LK 01) Long-term trends of global atmospheric composition
Erschienen in Atmospheric measurement techniques
Verlag Copernicus Publications
Band 14
Heft 1
Seiten 595–613
Vorab online veröffentlicht am 28.01.2021
Nachgewiesen in Dimensions
Web of Science
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