Formic acid above the Jungfraujoch during 1985–2007: observed variability,  seasonality, but no long-term background evolution

Zander, Rodolphe; Duchatelet, Pierre; Mahieu, Emmanuel; Demoulin, Philippe; Roland, G.; Servais, Christian; Auwera, J. Vander; Perrin, A.; Rinsland, C. P.; Crutzen, Paul J.

doi:10.5194/acpd-10-14771-2010

Cited by 3 publications

(3 citation statements)

References 70 publications

(72 reference statements)

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“…Satellite and infrared (IR) measurements have been made, but these are mainly at altitudes greater than 2 km. Zander et al (2010) reported an average mixing of ratio of 110.9 pptv in the 3.58 to 10.6 km region, which is comparable to the concentrations reported here. Satellite-based IR measurements have been made to altitudes of 5 km, where mixing ratios of 157 ± 60 have been recorded (González Abad et al, 2009), similar to the smaller plumes measured on flight B518.…”

Section: Observations Of Formic Acid Concentrationssupporting

confidence: 79%

Airborne observations of formic acid using a chemical ionization mass spectrometer

et al. 2012

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Abstract. The first airborne measurements of formic acid mixing ratios over the United Kingdom were measured on the FAAM BAe-146 research aircraft on 16 March 2010 with a chemical ionization mass spectrometer using I − reagent ions. The I − ionization scheme was able to measure formic acid mixing ratios at 1 Hz in the boundary layer.In-flight standard addition calibrations from a formic acid source were used to determine the instrument sensitivity of 35 ± 6 ion counts pptv −1 s −1 and a limit of detection of 25 pptv. Routine measurements were made through a scrubbed inlet to determine the instrumental background. Three plumes of formic acid were observed over the UK, originating from London, Humberside and Tyneside. The London plume had the highest formic acid mixing ratio throughout the flight, peaking at 358 pptv. No significant correlations of formic acid with NO x and ozone were found, but a positive correlation was observed between CO and HCOOH within the two plumes where coincident data were recorded.A trajectory model was employed to determine the sources of the plumes and compare modelled mixing ratios with measured values. The model underestimated formic acid concentrations by up to a factor of 2. This is explained by missing sources in the model, which were considered to be both primary emissions of formic acid of mainly anthropogenic origin and a lack of precursor emissions, such as isoprene, from biogenic sources, whose oxidation in situ would lead to formic acid formation.

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Section: Observations Of Formic Acid Concentrationssupporting

confidence: 79%

Airborne observations of formic acid using a chemical ionization mass spectrometer

et al. 2012

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“…The latter study gives insight on the seasonal variation of HCOOH, with a mean mixing ratio in the free troposphere from about 300 pptv in October-December to about 800 pptv in July-September, likely resulting from higher biogenic emissions during the growing season. Other groundbased measurements above Jungfraujoch were very recently analyzed over a 22 years period and show a similar seasonal cycle with a maximum occurring during summer as well as significant diurnal and day-to-day variability (Zander et al, 2010).…”

Section: Formic Acidmentioning

confidence: 99%

Global distributions of methanol and formic acid retrieved for the first time from the IASI/MetOp thermal infrared sounder

et al. 2011

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Abstract. Methanol (CH 3 OH) and formic acid (HCOOH) are among the most abundant volatile organic compounds present in the atmosphere. In this work, we derive the global distributions of these two organic species using for the first time the Infrared Atmospheric Sounding Interferometer (IASI) launched onboard the MetOp-A satellite in 2006. This paper describes the method used and provides a first critical analysis of the retrieved products. The retrieval process follows a two-step approach in which global distributions are first obtained on the basis of a simple radiance indexing (transformed into brightness temperatures), and then mapped onto column abundances using suitable conversion factors. For methanol, the factors were calculated using a complete retrieval approach in selected regions. In the case of formic acid, a different approach, which uses a set of forward simulations for representative atmospheres, has been used. In both cases, the main error sources are carefully determined: the average relative error on the column for both species is estimated to be about 50%, increasing to about 100% for the least favorable conditions. The distributions for the year 2009 are discussed in terms of seasonality and source identification. Time series comparing methanol, formic acid and carbon monoxide in different regions are also presented.

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“…The latter study gives insight on the seasonal variation of HCOOH, with a mean mixing ratio in the free troposphere from about 300 pptv in October-December to about 800 pptv in July-September, likely resulting from higher biogenic emissions during the growing season. Other ground-based measurements above Jungfraujoch were very recently analyzed over a 22 years period and show a similar seasonal cycle with a maximum occurring during summer as well as significant diurnal and day-to-day variability (Zander et al, 2010).…”

Section: Formic Acidmentioning

confidence: 85%

First global distributions of methanol and formic acid retrieved from the IASI/MetOp thermal infrared sounder

Razavi¹,

Karagulian²,

Clarisse³

et al. 2010

Preprint

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Methanol (CH<sub>3</sub>OH) and formic acid (HCOOH) are among the most abundant volatile organic compounds present in the atmosphere. Their role in tropospheric chemistry stems from their influence on the oxidizing capacity of the atmosphere and, in the case of HCOOH, from its influence on the acidity of clouds and precipitation. In this work, we derive the first global distributions of these two organic species using the Infrared Atmospheric Sounding Interferometer (IASI) launched onboard the MetOp-A satellite in 2006. This paper describes the method used and provides a first critical analysis of the retrieved products. The retrieval process follows a two-step approach in which global distributions are first obtained on the basis of a simple radiance indexing (transformed into brightness temperatures), and then mapped onto column abundances using suitable conversion factors. For methanol, the factors were calculated using a complete retrieval approach in selected regions. In the case of formic acid, a different approach, which uses a set of forward simulations for representative atmospheres, has been used. In both cases, the main error sources are carefully determined: the average relative error on the column for both species is estimated to be about 50%, increasing to about 100% for the least favorable conditions. The distributions for the year 2009 are discussed in terms of seasonality and source identification. Global correlations between methanol and formic acid as well as correlations between these two species and carbon monoxide are also presented and discussed

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Formic acid above the Jungfraujoch during 1985–2007: observed variability, seasonality, but no long-term background evolution

Cited by 3 publications

References 70 publications

Airborne observations of formic acid using a chemical ionization mass spectrometer

Airborne observations of formic acid using a chemical ionization mass spectrometer

Global distributions of methanol and formic acid retrieved for the first time from the IASI/MetOp thermal infrared sounder

First global distributions of methanol and formic acid retrieved from the IASI/MetOp thermal infrared sounder

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