MAX-DOAS detection of glyoxal during ICARTT 2004

[摘要] The direct detection of glyoxal (CHOCHO), the smallest α-dicarbonyl,in the open atmosphere by active differential optical absorptionspectroscopy (DOAS) has recently been demonstrated (Volkamer et al., 2005a)and triggered the very recent successful detection of CHOCHO from space(Kurosu et al., 2005; Wittrock et al., 2006; Beirle et al., 2006). Here wereport the first comprehensive analysis of CHOCHO by passive multi axisdifferential optical absorption spectroscopy (MAX-DOAS). CHOCHO and NO₂slant column measurements were conducted at the Massachusetts Institute ofTechnology (MIT), Cambridge, USA, and on board the research vessel Ron Brownin the Gulf of Maine as part of the International Consortium for AtmosphericResearch on Transport and Transformation (ICARTT) 2004 campaign. For a daywith nearly clear sky conditions, radiative transfer modeling was employedto derive diurnal CHOCHO mixing ratios in the planetary boundary layer (PBL)for both sites. CHOCHO mixing ratios at MIT varied from 40 to 140 ppt, withpeak values observed around noon. Mixing ratios over the Gulf of Maine werefound to be up to 2.5 times larger than at MIT. The CHOCHO-to-NO₂ ratioat MIT was <0.03, and enhancements of this ratio by up to two orders ofmagnitude were found over the Gulf of Maine. This paper focuses on themethodological aspects involved with MAX-DOAS measurements of CHOCHO.

[学科分类] 大气科学