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Proceedings Paper

On determination of formaldehyde content in atmospheric boundary layer for overcast using DOAS technique
Author(s): Oleg Postylyakov; Alexander Borovski; Victor Ivanov
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Paper Abstract

Formaldehyde (HCHO) is involved in a lot of chemical reactions in the atmosphere. Taking into account that HCHO basically undergo by photolysis and reaction with hydroxyl radical within a few hours, short-lived VOCs and direct HCHO emissions can cause local HCHO enhancement over certain areas, and, hence, exceeding background level of HCHO can be examined as a local pollution of the atmosphere by VOCs or existence of a local HCHO source. Several retrieval algorithms applicable for DOAS measurements in cloudless were previously developed. A new algorithm applicable for overcast and cloudless sky and its error analysis is briefly introduced by this paper. Analysis of our HCHO VCD retrieval for overcast shows that when one know the cloud base height, but doesn’t know cloud optical depth, the typical errors of HCHO total content retrieval are less than 10% for snow season, less than 5% for snow-free seasons, and reaches 40-45% for season with non-stable snow cover. In case one knows both the cloud base height and the cloud optical depth, the typical errors are about 5% for snow season, less than 2.5% for snow-free seasons, and are within about 10–30% for season with non-stable snow cover. Given above error estimations are valid if the HCHO layer is below the cloud base. The errors dramatically increase when HCHO layer penetrates into clouds in both cases. The first preliminary results of HCHO VCD retrieval for overcast are shown. The average difference of the HCHO VCDs for wind from Moscow megapolis and wind from few urbanized areas is about 0.8×1016 mol×cm-2 and approximately corresponds to estimates of influence of Moscow megapolis observed in clear-sky conditions.

Paper Details

Date Published: 19 November 2015
PDF: 10 pages
Proc. SPIE 9680, 21st International Symposium Atmospheric and Ocean Optics: Atmospheric Physics, 96804O (19 November 2015); doi: 10.1117/12.2205925
Show Author Affiliations
Oleg Postylyakov, A.M. Obukhov Institute of Atmospheric Physics (Russian Federation)
Alexander Borovski, A.M. Obukhov Institute of Atmospheric Physics (Russian Federation)
Victor Ivanov, Belarusian State Univ. (Russian Federation)
V.E. Zuev Institute of Atmospheric Optics (Belarus)


Published in SPIE Proceedings Vol. 9680:
21st International Symposium Atmospheric and Ocean Optics: Atmospheric Physics
Oleg A. Romanovskii, Editor(s)

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