20 November 2014 Measurements of formaldehyde total content using DOAS technique: a new retrieval method for overcast
Author Affiliations +
Abstract
Formaldehyde (HCHO) is a significant constituent of the atmospheric chemistry involved in a lot of chemical reactions, which principal global source is the intermediate oxidation of volatile organic compounds (VOCs). Taking into account that HCHO basically undergo by photolysis and reaction with hydroxyl radical within a few hours, isoprene together with other short-lived VOCs and direct HCHO emissions can cause local HCHO enhancement over certain areas, and, hence, cases with HCHO, that exceed some background level, can be examined as local pollution of the atmosphere by VOCs. HCHO has significant specific features in spectral structure of UV absorption cross-section to be measured using the differential optical absorption spectroscopy (DOAS) technique. 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 presented in this paper. In case we know the cloud base height, but don’t know cloud optical depth, the error of HCHO total content retrieval is about 10-20% for winter season, about 5% for summer season, and about 30-40% for transition season when the ABL is below the cloud base. In case we know both the cloud base height and cloud optical depth, the error is about 5-10% for winter season, less than 5% for summer season, and about 25-35% for transition season when the ABL is below the cloud base. The errors dramatically increase when clouds penetrate into ABL in both cases.
© (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Oleg Postylyakov, Oleg Postylyakov, Alexander Borovski, Alexander Borovski, } "Measurements of formaldehyde total content using DOAS technique: a new retrieval method for overcast", Proc. SPIE 9259, Remote Sensing of the Atmosphere, Clouds, and Precipitation V, 925918 (20 November 2014); doi: 10.1117/12.2069595; https://doi.org/10.1117/12.2069595
PROCEEDINGS
7 PAGES


SHARE
Back to Top