References

ACPD

Atmospheric Chemistry and Physics Discussions

ACPD

1680-7375

Copernicus GmbH

Göttingen, Germany

10.5194/acpd-10-14771-2010

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

Zander

¹ Duchatelet

¹ Mahieu

¹ Demoulin

¹ Roland

¹ Servais

¹ Vander Auwera

² Perrin

³ Rinsland

C. P.

⁴ Crutzen

⁵

Institute of Astrophysics and Geophysics, University of Liège, 4000, Liège, Belgium

Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles, 1050, Brussels, Belgium

Laboratoire Interuniversitaire de Systèmes Atmosphériques, CNRS, Université de Paris 12 et 7, 94010 Créteil cedex, France

NASA Langley Research Center, Hampton, VA 23681-2199, USA

Max Planck Institute for Chemistry, Airchemistry Division, Mainz, Germany

16 06 2010

10 6 14771 14814

This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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This paper reports on daytime total vertical column abundances of formic acid (HCOOH) above the Northern mid-latitude, high altitude Jungfraujoch station (Switzerland; 46.5° N, 8.0° E, 3580 m altitude). The columns were derived from the analysis of infrared solar observations regularly performed with high spectral resolution Fourier transform spectrometers during over 1537 days between September 1985 and September 2007. The investigation was based on the spectrometric fitting of five spectral intervals, one encompassing the HCOOH ν6 band Q branch at 1105 cm−1, and four additional ones allowing to optimally account for critical temperature-sensitive or timely changing interferences by other atmospheric gases, in particular HDO, CCl2F2 and CHClF2. The main results derived from the 22 yr long database indicate that the free tropospheric burden of HCOOH above the Jungfraujoch undergoes important short-term daytime variability, diurnal and seasonal modulations, inter-annual anomalies, but no statistically significant long-term background change at the 1-sigma level. A major progress in the remote determination of the atmospheric HCOOH columns reported here has resulted from the adoption of new, improved absolute spectral line intensities for the infrared ν6 band of trans-formic acid, resulting in retrieved free tropospheric loadings being about a factor two smaller than if derived with previous spectroscopic parameters. Implications of this significant change with regard to earlier remote measurements of atmospheric formic acid and comparison with relevant Northern mid-latitude in situ findings will be assessed critically. Sparse HCOOH model predictions will also be evoked.

References 1

Andreae,~M O., Talbot,~R W., Andreae,~T W., and Harriss,~R C.: Formic and acetic acids over the central Amazon region, Brazil, Part 1: Dry season, J. Geophys. Res., 93, 1616–1624, 1988.

Arlander,~D W., Cronn,~D R., Farmer,~J C., Menzia,~F A., and Westberg,~H H.: Gaseous oxygenated hydrocarbons in the remote marine troposphere, J. Geophys. Res., 96, 16391–16403, 1990.

Baboukas,~E D., Kanakidou,~M., and Mihalopoulos,~N.: Carboxylic acids in gas and particulate phase above the Atlantic Ocean, J. Geophys. Res., 105, 14459–14471, 2000.

Baltensperger,~U., Gäggeler,~H W., Jost,~D T., Lugauer,~M., Schwikowski,~M., Weingartner,~E., and Seibert,~P.: Aerosol climatology at the high-altitude site Jungfraujoch, Switzerland, J. Geophys. Res., 102, 19707–19715, 1997.

Bernath,~P F., McElroy,~C T., Abrams,~M C., Boone,~C D., Buttler,~M., Camy-Peyret,~C., Carleer,~M., Clerbaux,~C., Coheur,~P.-F., Colin,~R., DeCola,~P., De Mazière,~M., Drummond,~J R., Dufour,~D., Evans,~W F J., Fast,~H., Fussen,~D., Gilbert,~K., Jennings,~D E., Llewellyn,~E J., Lowe,~R P., Mahieu,~E., McConnell,~J C., McHugh,~M., McLeod,~S D., Michaud,~R., Midwinter,~C., Nassar,~R., Nichitiu,~F., Nowlan,~C., Rinsland,~C P., Rochon,~Y J., Rowlands,~N., Semeniuk,~K., Simon,~P., Skelton,~R., Sloan,~J J., Soucy,~M.-A., Strong,~K., Tremblay,~P., Turnbull,~D., Walker,~K A., Walkty,~I., Wardle,~D A., Wehrle,~V., Zander,~R., and Zou,~J.: Atmospheric Chemistry Experiment (ACE): mission overview, Geophys. Res. Lett., 32, L15S01, \doi10.1029/2005GL022386, 2005.

Boone,~C D., Nassar,~R., Walker,~K A., Rochon,~Y., McLeod,~S D., Rinsland,~C P., and Bernath,~P F.: Retrievals for the Atmospheric Chemistry Experiment Fourier transform spectrometer, Appl. Opt., 44, 7218–7231, 2005.

Brault,~J W.: Solar Fourier transform spectroscopy, in: Proceedings of the JOSO Workshop on Future Solar Optical Observations, Needs and Constraints, Firenze, Italy, edited by: Godoli,~G., Noci,~G., and Reghin,~A., Baccini and Chiappi, Florence, Italy, 32–52, 1978.

Chebbi,~A. and Carlier,~P.: Carboxylic acids in the troposphere, occurrence, sources and sinks: a~review, Atmos. Environ., 24, 4233–4249, 1996.

Christian,~T J., Kleis,~B., Yokelson,~R J., Holzinger,~R., Crutzen,~P J., Hao,~W M., Shirai,~T., and Blake,~D R.: Comprehensive laboratory measurements of biomass-burning emissions – Part 2: First intercomparison of open path FTIR, PTR-MS, and GC-MS/FID/ECD, J. Geophys. Res., 109, D02311, \doi10.1029/2003JD003874, 2004.

Connor,~B J., Parrish,~A., Tsou,~J.-J., and McCormick,~P.: Error analysis of the ground-based microwave ozone measurements during STOIC, J. Geophys. Res., 100, 9283–9291, 1995.

Delbouille,~L. and Roland,~G.: High resolution solar and atmospheric spectroscopy from the Jungfraujoch high-altitude station, Opt. Eng., 34(9), 2736–2739, 1995.

Farmer,~C B. and Norton,~R H.: A~High-Resolution Atlas of the Infrared Spectrum of the Sun and the Earth Atmosphere from Space, Vol. I The Sun, NASA Reference Publication 1224, 1989.

Forrer,~J., Rüttimann,~R., Schneiter,~D., Fischer,~A., Buchmann,~B., and Hofer,~P.: Variability of trace gases at the high-Alpine site Jungfraujoch caused by meteorological transport processes, J. Geophys. Res., 105, 12241–12251, 2000.

Friedl-Vallon,~F., Maucher,~G., Kleinert,~A., Lengel,~A., Keim,~C., Oelhaf,~H., Fischer,~H., Seefeldner,~M., and Trieschmann,~O.: Design and characterization of the balloon-borne Michelson Interferometer for Passive Atmospheric Sounding (MIPAS-2B), Appl. Opt., 47, 3335–3355, 2004.

Fuelberg,~H E., Hannan,~J R., van Velthoven,~P F J., Browell,~E V., Bieberbach Jr.,~G., Knabb,~R D., Gregory,~G L., Pickering,~K E., and Selkirk,~H B.: A~meteorological overview of the Subsonic Assessment Ozone and Nitrogen Oxide Experiment (SONEX) period, J. Geophys. Res., 105, 3633–3651, 2000.

Glasius,~M., Boel,~C., Bruun,~N., Easa,~L M., Hornung,~P., Klausen,~H S., Klitgaard,~K C., Lindeskov,~C., Møller,~C K., Nissen,~H., Petersen,~A P F., Kleefeld,~S., Boaretto,~E., Hansen,~T S., Heinmeier,~J., and Lohse,~C.: Relative contribution of biogenic and anthropogenic sources to formic and acetic acids in the atmospheric boundary layer,~J. Geophys. Res., 106, 7415–7426, 2001.

Goldman,~A. and Gillis,~J R.: Line parameters and line-by-line calculations for molecules of atmospheric interest. Technical report, Dept. of Physics, Univ. of Denver, CO, 1984.

Goldman,~A., Murcray,~F H., Murcray,~D G., and Rinsland,~C P.: A~search for formic acid in the upper troposphere: a~tentative identification of the 1105 cm−1 $\nu _6$ Q branch in high-resolution balloon-borne solar absorption spectra, Geophys. Res. Lett., 11, 307–310, 1984.

Gonz�lez Abad, G., Bernath, P. F., Boone, C. D., McLeod, S. D., Manney, G. L., and Toon, G. C.: Global distribution of upper tropospheric formic acid from the ACE-FTS, Atmos. Chem. Phys., 9, 8039–8047, doi:10.5194/acp-9-8039-2009, 2009.

Hahn,~C J., Merrill,~J T., and Mendonca,~B G.: Meteorological influences during MLOPEX, J. Geophys. Res., 97, 10291–10309, 1992.

Hartmann,~W R., Andreae,~M O., and Helas,~G.: Measurements of organic acids over central Germany, Atmos. Environ., 23, 1531–1533, 1989.

Hartmann,~W R., Santana,~M., Hermoso,~M., Andreae,~M O., and Sanhueza,~E.: Diurnal cycles of formic and acetic acids in the northern part of the Guyana shield, Venezuela, J. Atmos. Chem., 13, 63–72, 1991.

Hocking,~W H.: The other rotamer of formic acid, cis-HCOOH, Z. Natur Forschung Serie A, Nr. 142, 1113–1121, 1976.

Irion,~F W., Gunson,~M R., Toon,~G C., Brown,~L R., Chang,~A Y., Eldering,~A., Mahieu,~E., Manney,~G L., Michelsen,~H A., Moyer,~E J., Newchurch,~M J., Osterman,~G B., Rinsland,~C P., Salawitch,~R J., Sen,~B., Yung,~Y L., and Zander,~R.: Atmospheric Trace Molecule Spectroscopy Experiment (ATMOS) version 3 data retrievals, Appl. Opt., 41(33), 6968–6979, 2002.

Ito,~A., Sillman,~S., and Penner,~J E.: Effects of additional nonmethane volatile organic compounds, organic nitrates, and direct emissions of oxygenated organic species on global tropospheric chemistry, J. Geophys. Res., 112, D06309, \doi10.1029/2005JD006556, 2007.

Jaeglé,~L., Jacob,~D J., Brune,~W H., Faloona,~I., Tan,~D., Heikes,~B G., Kondo,~Y., Sachse,~G W., Anderson,~B., Gregory,~G L., Singh,~H B., Pueschel,~R., Ferry,~G., Blake,~D R., and Shetter,~R E.: Photochemistry of \chemHO_x in the upper troposphere at northern midlatitudes, J. Geophys. Res., 105, 3877–3892, 2000.

Kajii,~Y., Akimoto,~H., Komazaki,~Y., Tanaka,~S., Mukai,~H., Murano,~K., and Merrill,~J T.: Long-range transport of ozone, carbon monoxide, and acidic trace gases at Oki Island, Japan, during PEM-WEST/PEACAMPOT B campaign, J. Geophys. Res., 102, 28637–28649, 1997.

Kanakidou,~M. and Crutzen,~P J.: The photochemical source of carbon monoxide: importance, uncertainties and feedbacks, Chemosph. Global Change Sci., 1, 91–109, 1999.

Keene,~W C. and Galloway,~J N.: The biogeochemical cycling of formic and acetic acids through the troposphere: An overview of current understanding, Tellus B, 40, 322–344, 1988.

Keene,~W C., Talbot,~R W., Andreae,~M O., Beecher,~K., Berresheim,~H., Castro,~M., Farmer,~J C., Galloway,~J N., Hoffman,~M R., Li,~S.-M., Maben,~J R., Munger,~J W., Norton,~R B., Pszenny,~A A P., Puxbaum,~H., Westberg,~H., and Winiwarter,~W.: An intercomparison of measurement systems for vapour- and particulate-phase concentrations of formic and acetic acids, J. Geophys. Res., 94, 6457–6472, 1989.

Kesselmeier,~J. and Staudt,~M.: Biogenic volatile organic compounds (VOC): an overview on emission, physiology and ecology, J. Atmos. Chem., 33, 23–88, 1999.

Khare,~P., Kumar,~N., Kumari,~K M., and Srivastava,~S S.: Atmospheric formic and acetic acids: an overview, Rev. Geophys., 37, 227–248, 1999.

Khwaja,~H A.: Atmospheric concentration of carboxylic acids and related compounds at a~semi-rural site, Atmos. Environ., 29, 127–139, 1995.

Klemm,~O., Talbot,~R W., Fitzgerald,~D R., Klemm,~K I., and Lefer,~B L.: Low to middle tropospheric profiles and biosphere/troposphere fluxes of acidic gases in the summertime Canadian taiga, J. Geophys. Res., 99, 1687–1698, 1994.

Legrand,~M., Preunkert,~S., Wagenbach,~D., Cachier,~H., and Puxbaum,~H.: A~historical record of formate and acetate from a~high-elevation Alpine glacier: implications for their natural versus anthropogenic budgets at the European scale, J. Geophys. Res., 108(D24), 4788, \doi10.1029/2003JD003594, 2003.

Legrand,~M., Preunkert,~S., Jourdan,~B., and Aumont,~B.: Year-round records of gas and particulate formic and acetic acids in the boundary layer at Dumont d'Urville, coastal Antarctic, J. Geophys. Res., 109, D06313, \doi10.1029/2003JD003786, 2004.

Liu,~S C., McAfee,~J R., and Cicerone,~R J.: Radon 222 and tropospheric vertical transport, J. Geophys. Res., 89, 7291–7297, 1984.

Mahieu,~E., Zander,~R., Demoulin,~P., De Mazière,~M., Mélen,~F., Servais,~C., Roland,~G., Delbouille,~L., Poels,~J., and Blomme,~R.: Fifteen years-trend characteristics of key stratospheric constituents monitored by FTIR above the Jungfraujoch, in: Proc of the Fifth European Symposium on Stratospheric Ozone, edited by Harris,~N R P., Guirlet,~M., and Amanatidis,~G T., 27 September–1 October 1999, St. Jean de Luz, France. Air Pollution Research Report 73, 99–102, 2000.

Mahieu,~E., Servais,~C., Duchatelet,~P., Zander,~R., Demoulin,~P., De Mazière,~M., Senten,~C., Walker,~K A., Boone,~C D., Rinsland,~C P., and Bernath,~P.: Optimisation of retrieval strategies using Jungfraujoch high-resolution FTIR observations for long-term trend studies and satellite validation, in: Observing Tropospheric Trace Constituents from Space, ACCENT-TROPOSAT-2 in 7-2006, edited by: Burrows,~J. and Borrell,~P., 280–285, 2007.

Meier,~A., Toon,~G C., Rinsland,~C P., Goldman,~A., Hase,~F.: Spectroscopic atlas of atmospheric microwindows in the middle-infrared. IRF Technical Report 048, ISSN 0284–1738, Printed by Swedish Institute of Space Physics, Kiruna, Sweden, 2004.

Migeotte,~M V., Neven,~L., and Swensson,~J.: The solar spectrum from 2.8 to 23.7 μm: Part 1: Photometric atlas. Mém. S. R. Sci. Liège; Special Vol. 1, 1956.

Moody,~J L., Pszenny,~A A P., Gaudry,~A., Keene,~W C., Galloway,~J N., and Polian,~G.: Precipitation composition and its variability in the Southern Indian ocean: Amsterdam island, 1980–1987, J. Geophys. Res., 96, 20769–20786, 1991.

Nazarov,~L E., Kuzenkov,~A F., Malakhov,~S G., Volokitina,~L A., Gaziyev,~Ya I., and Vasil'yev,~A S.: Radioactive aerosol distribution in the middle and upper troposphere over the USSR in 1963–1968, J. Geophys. Res., 75, 3575–3588, doi:10.1029/jc075i018p03575, 1970.

Norton,~R B.: Measurements of gas phase formic and acetic acids at the Mauna Loa Observatory, Hawaii, during the Mauna Loa Observatory Photochemistry Experiment 1988,~J. Geophys. Res., 97, 10389–10393, 1992.

Notholt,~J., Cappellani,~F., Roesdahl,~H., and Restelli,~G.: Absolute infrared band intensities and air broadening coefficients for spectroscopic measurements of formic acid in air, Spectrochim. Acta A, 47, 477–483, 1991.

Perrin,~A., Rinsland,~C P., and Goldman,~A.: Spectral parameters for the $\nu_6$ region of HCOOH and the measurement in the infrared tropospheric spectrum, J. Geophys. Res, 104, 18661–18666, 1999.

Perrin,~A. and Vander Auwera,~J.: An improved database for the 9-μm region of the formic acid spectrum, J. Quant. Spectrosc. Radiat. Transfer, 108, 363–370, 2007.

Poisson,~N., Kanakidou,~M., and Crutzen,~P J.: Impact of non-methane hydrocarbons on tropospheric chemistry and oxidizing power of the global troposphere: 3-dimensional modelling results,~J. Atmos. Chem., 36, 157–230, 2000.

Pougatchev,~N S., Connor,~B J., and Rinsland,~C P.: Infrared measurements of the ozone vertical distribution above Kitt Peak, J. Geophys. Res., 100, 16689–16697, 1995.

Prospero,~J M., Savoie,~D L., Ness,~R T., Duce,~R A., and Merrill,~J.: Particulate sulphate and nitrate in the boundary layer over the North Pacific Ocean, J. Geophys. Res., 90, 10586–10596, 1985.

Pszenny,~A A P., Puxbaum,~H., Westberg,~H., and Winiwarter,~W.: An intercomparison of measurement systems for vapor- and particulate-phase concentrations of formic and acetic acids, J. Geophys. Res., 94, 6457–6472, 1989.

Puxbaum,~H., Rosenberg,~C., Gregori,~M., Lanzerstorfer,~C., Ober,~E., and Winiwarter,~W.: Atmospheric concentrations of formic and acetic acids and related compounds in Eastern and Northern Austria, Atmos. Environ., 22, 2841–2850, 1988.

Reiner,~T., Möhler,~O., and Arnold,~F.: Measurements of acetone, acetic acid, and formic acid in the northern midlatitude upper troposphere and lower stratosphere, J. Geophys. Res., 104, 13943–13952, 1999.

Remedios, J. J., Allen, G., Waterfall, A. M., Oelhaf, H., Kleinert, A., and Moore, D. P.: Detection of organic compound signatures in infra-red, limb emission spectra observed by the MIPAS-B2 balloon instrument, Atmos. Chem. Phys., 7, 1599–1613, doi:10.5194/acp-7-1599-2007, 2007.

Rinsland,~C P., Jones,~N B., Connor,~B J., Logan,~J A., Pougatchev,~N S., Goldman,~A., Murcray,~F J., Stephen,~T M., Pine,~A S., Zander,~R., Mahieu,~E., and Demoulin,~P.: Northern and Southern Hemisphere ground-based infrared spectroscopic measurements of tropospheric carbon monoxide and ethane, J. Geophys. Res., 103, 28197–28217, 1998.

Rinsland,~C P., Mahieu,~E., Zander,~R., Goldman,~A., Wood,~S., and Chiou,~L S.: Free tropospheric measurements of formic acid (HCOOH) from infrared ground-based solar absorption spectra: retrieval approach, evidence for a~seasonal cycle, and comparison with model calculations, J. Geophys. Res., 109, D1803, \doi10.1029/2004JD004917, 2004.

Rinsland,~C P., Boone,~C D., Bernath,~P F., Mahieu,~E., Zander,~R., Dufour,~G., Clerbaux,~C., Turquety,~S., Chiou,~L., McConnell,~J C., Neary,~L., and Kaminsky,~J W.: First space-based observations of formic acid (HCOOH): Atmospheric Chemistry Experiment austral spring 2004 and 2005 Southern Hemisphere tropical-mid-latitude upper tropospheric measurements, Geophys. Res. Lett., 33, L23804, \doi10.1029/2006GL027128, 2006.

Rinsland,~C P., Turquety,~S., Clerbaux,~C., Dufour,~G., Coheur,~P.-F., Boone,~C D., Bernath,~P F., and Chiou,~L S.: Satellite boreal measurements over Alaska and Canada during June–July 2004: Simultaneous measurements of upper tropospheric CO, \chemC_2H_6, HCN, \chemCH_3Cl, \chemCH_4, \chemC_2H_2, \chemCH_3OH, HCOOH, OCS, and \chemSF_6, Global Biogeochem. Cy., 21, GB3008, \doi10.1029/2006GB002795, 2007.

Rodgers,~C D.: Retrieval of atmospheric temperature and composition from remote measurements of thermal radiation, Rev. Geophys., 14, 609–624, 1976.

Rothman,~L S., Barbe,~A., Benner,~D C., Brown,~L R., Camy-Peyret,~C., Carleer,~M R., Chance,~K V., Clerbaux,~C., Devi,~V M., Fayt,~A., Flaud,~J.-M., Gamache,~R R., Goldman,~A., Jacquemart,~D., Jucks,~K W., Lafferty,~W J., Mandin,~J.-Y., Massie,~S T., Nemtchinov,~V., Newnham,~D A., Perrin,~A., Rinsland,~C P., Schroeder,~J., Smith,~J., Smith,~M A H., Tang,~K., Toth,~R A., Vander Auwera,~J., Varanasi,~P., and Yoshino,~K.: The HITRAN molecular spectroscopic database: edition of 2000 including updates through 2001, J. Quant. Spectrosc. Radiat. Transfer, 82, 5–44, 2003.

Rothman,~L S., Jacquemart,~D., Barbe,~A., Chris Benner,~D., Birk,~M., Brown,~L R., Carleer,~M R., Chackerian Jr.,~C., Chance,~K., Coudert,~L H., Dana,~V., Devi,~V M., Flaud,~J.-M., 30 Gamache,~R R., Goldman,~A., Hartmann,~J.-M., Jucks,~K W., Maki,~A G., Mandin,~J.-Y., Massie,~S T., Orphal,~J., Perrin,~A., Rinsland,~C P., Smith,~M A H., Tennyson,~J., Tolchenov,~R N. , Toth,~R A., Vander Auwera,~J., Varanasi,~P., and Wagner,~G.: The HITRAN 2004 molecular spectroscopic database, J. Quant. Spectrosc. Radiat. Transfer, 96, 139–204, 2005.

Rothman,~L S., Gordon,~I E., Barbe,~A., Benner,~D C., Bernath,~B E., Birk,~M., Boudon,~V., Brown,~L R., Campargue,~A., Champion,~J P., Chance,~K., Coudert,~L H., Dana,~V., Devi,~V M., Fally,~S., Flaud,~J.-M., Gamache,~R R., Goldman,~A., Jacquemart,~D., Kleiner,~I., Lacome,~N., Lafferty,~W J., Mandin,~J Y., Massie,~S T., Mikhailenko,~S N., Miller,~C E., Moazzen-Ahmadi,~N., Naumenko,~O V., Nikitin,~A V., Orphal,~J., Perevalov,~V I., Perrin,~A., Predoi-Cross,~A., Rinsland,~C P., Rotger,~M., Simeckova,~M., Smith,~M A H., Sung,~K., Tashkun,~S A., Tennyson,~J., Toth,~R A., Vandaele,~A C., and Vander Auwera,~J.: The HITRAN 2008 molecular spectroscopy database, J. Quant. Spectrosc. Radiat. Transfer 110, 533–572, \doi10.1016/jqsrt.2009.02.013, 2009.

Sanhueza,~E., Santana,~M., Trapp,~D., Serves,~C., Figueroga,~L., Romero,~R., Rondon,~A., and Donoso,~L.: Field measurement evidences for an atmospheric chemical source of formic and acetic acids in the tropics, Geophys. Res. Lett., 23, 1045–1048, 1996.

Shephard,~M W., Goldman,~A., Clough,~S A., and Mlawer,~E J.: Spectroscopic improvements providing evidence of formic acid in AERI-LBLRTM validation spectra, J. Quant. Spectrosc. Radiat. Transfer, 82, 383–390, 2003.

Singh,~H., Chen,~Y., Tabazadeh,~A., Fukui,~Y., Bey,~I., Yantosca,~R., Jacob,~D., Arnold,~F., Wohlfrom,~K., Atlas,~E., Flocke,~F., Blake,~D., Blake,~N., Heikes,~B., Snow,~J., Talbot,~R., Gregory,~G., Sachse,~G., Vay,~S., and Kondo,~Y.: Distribution and fate of selected oxygenated organic species in the troposphere and lower stratosphere over the Atlantic, J. Geophys. Res., 105, 3795–3805, 2000.

Talbot,~R W., Beecher,~K M., Harris,~R C., Browell,~E V., and Coffer,~W R.: Atmospheric geochemistry of formic and acetic acids at a~midlatitude temperate site, J. Geophys. Res., 93, 1638–1652, 1988.

Talbot,~R W., Andreae,~M O., Berresheim,~H., Jacob,~D J., and Beecher,~K M.: Sources and sinks of formic, acetic and pyruvic acids over central Amazonia – Part 2: Wet season, J. Geophys. Res., 95, 16799–16811, 1990.

Talbot,~R W., Mosher,~R W., Heikes,~B G., Jacobs,~D J., Munger,~J W., Daube,~B C., Keene,~W C., Maben,~J R., and Artz,~R S.: Carboxylic acids in the rural continental atmosphere over the eastern United States during the Shenandoah Cloud and Photochemistry Experiment, J. Geophys. Res., 100, 9335–9343, 1995.

Talbot,~R W., Dibb,~J E., Klemm,~K I., Bradshaw,~J D., Sandholm,~S T., Blake,~D R., Sachse,~G W., Collins,~J., Heikes,~B G., Gregory,~G L., Anderson,~B E., Singh,~H B., Thornton,~D C., and Merrill,~J T.: Chemical characteristics of continental outflow from Asia to the troposphere over the Western Pacific Ocean during September–October 1991: results from PEM-West A, J. Geophys. Res., 101, 1713–1725, 1996a.

Talbot,~R W., Bradshaw,~J D., Sandholm,~S T., Smyth,~S., Blake,~D R., Blake,~N J., Sachse,~G W., Collins,~J E., Heikes,~B G., Anderson,~B E., Gregory,~G L., Singh,~H B., Singer,~B L., and Bachmeier,~A S.: Chemical characteristics of continental outflow over the tropical South Atlantic Ocean from Brazil and Africa, J. Geophys. Res., 101, 24187–24202, 1996b.

Talbot,~R W., Dibb,~J E., Lefer,~B L., Bradshaw,~J D., Sandholm,~S T., Blake,~D R., Blake,~N J., Sachse,~G W., Collins,~J E.Jr., Heikes,~B G., Merrill,~J T., Gregory,~G L., Anderson,~B E., Singh,~H B., Thornton,~D C., Bandy,~A R., and Pueschel,~R F.: Chemical characteristics of continental outflow from Asia to the troposphere over the Western Pacific Ocean during February–March 1994: results from PEM-West B, J. Geophys. Res., 102, 28255–28274, 1997a.

Talbot,~R W., Dibb,~J E., Lefer,~B L., Scheuer,~E M., Bradshaw,~J D., Sandholm,~R T., Smyth,~S., Blake,~D R., Blake,~N J., Sachse,~G W., Collins,~J E., and Gregory,~G L.: Large-scale distribution of tropospheric nitric, formic, and acetic acids over the western Pacific basin during wintertime, J. Geophys. Res., 102, 28303–28313, 1997b.

Toon,~G C.: The JPL MKIV interferometer, Opt. Photonics News, 2(10), 19–21, 1991.

Vander Auwera,~J., Didriche,~K., Perrin,~A., Keller,~F., and Flaud,~J.-M.: Absolute intensities in the $\nu_6$ band of trans-formic acid. Paper RB11 presented at the 59th International Symposium on Molecular Spectroscopy, Ohio State Univ., Columbus, Ohio, 21–25 June, 2004.

Vander Auwera,~J., Didriche,~K., Perrin,~A., and Keller,~F.: Absolute line intensities for formic acid and dissociation constant of the dimer, J. Chem. Phys., 126, 124311–124319, 2007.

Von Kuhlmann,~R., Lawrence,~G., Crutzen,~P J., and Rasch,~P J.: A~model for studies of tropospheric ozone and nonmethane hydrocarbons: model evaluation of ozone-related species, J. Geohys. Res., 108(D23), 4729, \doi10.1029/2002JD003348, 2003.

Zander,~R., Mahieu,~E., Demoulin,~P., Duchatelet,~P., Servais,~C., Roland,~G., Delbouille,~L., De Mazière,~M., and Rinsland,~C P.: Evolution of a~dozen non-\chemCO_2 greenhouse gases above Central Europe since the mid-1980s, Environmental Sciences, 2(2–3), 295–303, 2005.

Zander,~R., Mahieu,~E., Demoulin,~P., Duchatelet,~P., Roland,~G., Servais,~C., De Mazière,~M., Reimann,~S., and Rinsland,~C P.: Our changing atmosphere: evidence based on long-term infrared solar observations at the Jungfraujoch since 1950, Sci. Total Environ., 391, 184–195, 2008.