ACE-FTS observation of a young biomass burning plume: first reported measurements of C<sub>2</sub>H<sub>4</sub>, C<sub>3</sub>H<sub>6</sub>O, H<sub>2</sub>CO and PAN by infrared occultation from space

Abstract

Abstract. In the course of our study of the upper tropospheric composition with the infrared Atmospheric Chemistry Experiment -Fourier Transform Spectrometer (ACE-FTS), we found an occultation sequence that on 8 October 2005, sampled a remarkable plume near the east coast of Tanzania. Model simulations of the CO distribution in the Southern hemisphere are performed for this period and they suggest that the emissions for this event likely originated from a nearby forest fire, after which the plume was transported from the source region to the upper troposphere. Taking advantage of the very high signal-to-noise ratio of the ACE-FTS spectra over a wide wavenumber range (750-4400 cm −1 ), we present in-depth analyses of the chemical composition of this plume in the middle and upper troposphere, focusing on the measurements of weakly absorbing pollutants. For this specific biomass burning event, we report simultaneous observations of an unprecedented number of organic species. Measurements of C 2 H 4 (ethene), C 3 H 4 (propyne), H 2 CO (formaldehyde), C 3 H 6 O (acetone) and CH 3 COO 2 NO 2 (peroxyacetylnitrate, abbreviated as PAN) are the first reported detections using infrared occultation spectroscopy from satellites. Based on the lifetime of the emitted species, we discuss the photochemical age of the plume and also report, whenever possible, the enhancement ratios relative to CO.

Emission Ratios for Ammonia and Formic Acid and Observations of Peroxy Acetyl Nitrate (PAN) and Ethylene in Biomass Burning Smoke as Seen by the Tropospheric Emission Spectrometer (TES)

“…The solid he scan of f Figure 10b shows this residual feature, which partially overlaps with the strong CO 2 line [39] that is visible in the TES spectrum shown in Figure 10a. Figure 10c shows that the addition of a hypothetical C 2 H 4 profile to the model (with a peak concentration of 1.9 ppb at the surface) removes this feature.…”

“…Satellite retrievals of PAN could provide substantial information on the fate of NO x emitted by biomass burning in the atmosphere and the impact of these NO x emissions on global tropospheric ozone. The limb-viewing sounders MIPAS [38] and ACE-FTS [39] and the nadir-viewing IASI instrument [9,10] have all previously identified PAN in biomass burning smoke, but this species had not been previously detected in TES spectra.…”

“…As this rapid oxidation of ethylene impacts the ozone formation rate within young smoke plumes [40], better estimates of the emissions of ethylene from biomass burning could help to reduce the uncertainty in the impact of biomass burning on tropospheric ozone. Enhanced mixing ratios of ethylene were measured in TES prototype airborne measurements of western wildfires [18], and C 2 H 4 has also been previously identified by ACE-FTS [39] and IASI [9,10], but it had not been previously detected in TES spectra.…”

ACE-FTS observations of pyrogenic trace species in boreal biomass burning plumes during BORTAS

“…A number of studies have been previously conducted using remote measurements of biomass burning emissions from ACE-FTS Coheur et al, 2007) as well as other space-borne instruments Glatthor et al, 2009;Torres et al, 2009;Turquety et al, 2009). Rinsland et al (2005) first explored the possibility of using ACE-FTS to study the emission of longer lived primary pyrogenic species and their long-range transport to establish the effectiveness of ACE-FTS in measuring the emission of trace species from biomass burning.…”

ACE-FTS measurements of trace species in the characterization of biomass burning plumes

“…Previous studies of biomass burning emissions have been performed using ACE-FTS Coheur et al, 2007) as well as a variety of other spaceborne instruments Coheur et al, 2009;Glatthor et al, 2009;Torres et al, 2009). The initial work conducted using ACE-FTS studied the emission of longerlived primary pyrogenic species and their long-range transport to establish the effectiveness of ACE-FTS in measuring the emission of trace species from biomass burning .…”