Journal Articles

Recurring South Asian smog episodes: Call for regional cooperation and improved monitoring

• South Asia stands out globally for fine particle pollution.
• The precise nature, sources, and potential transboundary impacts of air pollutants have been understudied in South Asia.
• Imbalanced AQ monitoring capacity is an impediment to regional cooperation that is critical in addressing air pollution.
• Revitalization of the Mal ́e Declaration would be one way to make progress.

More information here: https://www.sciencedirect.com/science/article/abs/pii/S1352231022005994?via%3Dihub

Key challenges for tropospheric chemistry in the Southern Hemisphere 

This commentary paper from the recently formed International Global Atmospheric Chemistry (IGAC) Southern Hemisphere Working Group outlines key issues in atmospheric composition research that particularly impact the Southern Hemisphere. In this article, we present a broad overview of many of the challenges for understanding atmospheric chemistry in the Southern Hemisphere, before focusing in on the most significant factors that differentiate it from the Northern Hemisphere. We present sections on the importance of biogenic emissions and fires in the Southern Hemisphere, showing that these emissions often dominate over anthropogenic emissions in many regions. We then describe how these and other factors influence air quality in different parts of the Southern Hemisphere. Finally, we describe the key role of the Southern Ocean in influencing atmospheric chemistry and conclude with a description of the aims and scope of the newly formed IGAC Southern Hemisphere Working Group.

Countries of the Indo-Gangetic Plain must unite against air pollution

International project of monitoring, analysis, and prediction of air quality and some essential questions (in Chinese). Wang X Y, Zhao D F, Ouyang H L, et al. Climate Change Research, 2020, 16 (1): 130-132.

Fostering multidisciplinary research on interactions between chemistry, biology, and physics within the coupled cryosphere-atmosphere system. Thomas, J.L., Stutz, J., Frey, M.M., Bartels-Rausch, T., Altieri, K., Baladima, F., Browse, J., Dall’Osto, M., Marelle, L., Mouginot, J., Murphy, J.G., Nomura, D., Pratt, K.A., Willis, M.D., Zieger, P., Abbatt, J., Douglas, T.A., Facchini, M.C., France, J., Jones, A.E., Kim, K., Matrai, P.A., McNeill, V.F., Saiz-Lopez, A., Shepson, P., Steiner, N., Law, K.S., Arnold, S.R., Delille, B., Schmale, J., Sonke, J.E., Dommergue, A., Voisin, D., Melamed, M.L. and Gier, J., 2019. Elem Sci Anth, 7(1), p.58. DOI: 10.1525/elementa.396.

Tropospheric Ozone Assessment Report: Tropospheric ozone from 1877 to 2016, observed levels, trends and uncertainties. Tarasick, D., Galbally, I.E., Cooper, O.R., Schultz, M.G., Ancellet, G., Leblanc, T., Wallington, T.J., Ziemke, J., Liu, X., Steinbacher, M., Staehelin, J., Vigouroux, C., Hannigan, J.W., García, O., Foret, G., Zanis, P., Weatherhead, E., Petropavlovskikh, I., Worden, H., Osman, M., Liu, J., Chang, K.-L., Gaudel, A., Lin, M., Granados-Muñoz, M., Thompson, A.M., Oltmans, S.J., Cuesta, J., Dufour, G., Thouret, V., Hassler, B., Trickl, T. and Neu, J.L., 2019. Tropospheric Ozone Assessment Report: Tropospheric ozone from 1877 to 2016, observed levels, trends and uncertainties. Elem Sci Anth, 7(1), p.39. DOI : 10.1525/elementa.376.

Ensemble forecasts of air quality in eastern China – Part 2: Evaluation of the MarcoPolo–Panda prediction system, version 1. Petersen, A. K., Brasseur, G. P., Bouarar, I., Flemming, J., Gauss, M., Jiang, F., Kouznetsov, R., Kranenburg, R., Mijling, B., Peuch, V.-H., Pommier, M., Segers, A., Sofiev, M., Timmermans, R., van der A, R., Walters, S., Xie, Y., Xu, J., and Zhou, G.: , Geosci. Model Dev., 12, 1241–1266, DOI: 10.5194/gmd-12-1241-2019, 2019.

Ensemble forecasts of air quality in eastern China – Part 1: Model description and implementation of the MarcoPolo–Panda prediction system, version 1. Brasseur, G. P., Xie, Y., Petersen, A. K., Bouarar, I., Flemming, J., Gauss, M., Jiang, F., Kouznetsov, R., Kranenburg, R., Mijling, B., Peuch, V.-H., Pommier, M., Segers, A., Sofiev, M., Timmermans, R., van der A, R., Walters, S., Xu, J., and Zhou, G.: , Geosci. Model Dev., 12, 33-67, doi: 10.5194/gmd-12-33-2019, 2019.

Five steps to improve air-quality forecasts. Kumar, R., Peuch, V.-H., Crawford, J., and Brasseur, G. P., Nature, 561, 27-29, doi: 10.1038/d41586-018-06150-5, 2018.

Local Arctic air pollution: A neglected but serious problem (2018),  Schmale, J., S.R. Arnold, K.S. Law, T. Throp, S. Anenberg, W.R. Simpson, J. Mao, and K.A. Pratt. Earth's Future, 6, doi:10.1029/2018EF000952.

Chemistry-Climate Model Initiative (CCMI) Special Issue (2016-2018) Eds. B. N. Duncan, A. Gettelman, P. Hess, G. Myhre, and P. Young. Atmospheric Chemistry and Physics, Atmospheric Measurement Techniques, Earth System Science Data, and Geoscientific Model Development.

Tropospheric Ozone Assessment Report: Present-day tropospheric ozone distribution and trends relevant to vegetation. Mills G, Pleijel H, Malley CS, Sinha B, Cooper OR, Schultz MG, Neufeld HS, Simpson D, Sharps K,  Feng Z,  Gerosa G,  Harmens H, Kobayashi K,  Saxena P,  Paoletti E,  Sinha V, Xu X,. Elem Sci Anth. 2018;6(1):47. DOI: 10.1525/elementa.302.

Tropospheric Ozone Assessment Report: Present-day distribution and trends of tropospheric ozone relevant to climate and global atmospheric chemistry model evaluation. Gaudel, A., Cooper, O.R., Ancellet, G., Barret, B., Boynard, A., Burrows, J.P., Clerbaux, C., Coheur, P.-F., Cuesta, J., Cuevas, E., Doniki, S., Dufour, G., Ebojie, F., Foret, G., Garcia, O., Granados Muños, M.J., Hannigan, J.W., Hase, F., Huang, G., Hassler, B., Hurtmans, D., Jaffe, D., Jones, N., Kalabokas, P., Kerridge, B., Kulawik, S.S., Latter, B., Leblanc, T., Le Flochmoën, E., Lin, W., Liu, J., Liu, X., Mahieu, E., McClure-Begley, A., Neu, J.L., Osman, M., Palm, M., Petetin, H., Petropavlovskikh, I., Querel, R., Rahpoe, N., Rozanov, A., Schultz, M.G., Schwab, J., Siddans, R., Smale, D., Steinbacher, M., Tanimoto, H., Tarasick, D.W., Thouret, V., Thompson, A.M., Trickl, T., Weatherhead, E., Wespes, C., Worden, H.M., Vigouroux, C., Xu, X., Zeng, G. and Ziemke, J., 2018. Elem Sci Anth, 6(1), p.39. DOI: 10.1525/elementa.291.

Tropospheric ozone assessment report: Global ozone metrics for climate change, human health, and crop/ecosystem research. Lefohn, AS, Malley, CS, Smith, L, Wells, B, Hazucha, M, Simon, H, Naik, V, Mills, G, Schultz, MG, Paoletti, E, De Marco, A, Xu, X, Zhang, L, Wang, T, Neufeld, HS, Musselman, RC, Tarasick, D, Brauer, M, Feng, Z, Tang, H, Kobayashi, K, Sicard, P, Solberg, S and Gerosa, G 2018. Elem Sci Anth, 6: 28. DOI: 10.1525/elementa.279. 

Tropospheric Ozone Assessment Report: Present-day ozone distribution and trends relevant to human health. Fleming, Z.L., Doherty, R.M., von Schneidemesser, E., Malley, C.S., Cooper, O.R., Pinto, J.P., Colette, A., Xu, X., Simpson, D., Schultz, M.G., Lefohn, A.S., Hamad, S., Moolla, R., Solberg, S. and Feng, Z., 2018. Elem Sci Anth, 6(1), p.12. DOI: 10.1525/elementa.73.

Tropospheric Ozone Assessment Report: Assessment of global-scale model performance for global and regional ozone distributions, variability, and trends. Young, P.J., Naik, V., Fiore, A.M., Gaudel, A., Guo, J., Lin, M.Y., Neu, J.L., Parrish, D.D., Rieder, H.E., Schnell, J.L., Tilmes, S., Wild, O., Zhang, L., Ziemke, J.R., Brandt, J., Delcloo, A., Doherty, R.M., Geels, C., Hegglin, M.I., Hu, L., Im, U., Kumar, R., Luhar, A., Murray, L., Plummer, D., Rodriguez, J., Saiz-Lopez, A., Schultz, M.G., Woodhouse, M.T. and Zeng, G., 2018. Elem Sci Anth, 6(1), p.10. DOI: 10.1525/elementa.265.

Anthropogenic fugitive, combustion and industrial dust is a significant, underrepresented fine particulate matter source in global atmospheric models (2017). Philip, S., R. V. Martin, G. Snider, C. Weagle, A. van Donkelaar, M. Brauer, D. Henze, Z. Klimont, C. Venkataraman, S. Guttikunda and Q. Zhang,, Environ. Res. Lett., doi:10.1088/1748-9326/aa65a4.

Tropospheric Ozone Assessment Report: Database and Metrics Data of Global Surface Ozone Observations. Schultz, M.G., Schröder, S., Lyapina, O., Cooper, O., Galbally, I., Petropavlovskikh, I., von Schneidemesser, E., Tanimoto, H., Elshorbany, Y., Naja, M., Seguel, R., Dauert, U., Eckhardt, P., Feigenspahn, S., Fiebig, M., Hjellbrekke, A.-G., Hong, Y.-D., Christian Kjeld, P., Koide, H., Lear, G., Tarasick, D., Ueno, M., Wallasch, M., Baumgardner, D., Chuang, M.-T., Gillett, R., Lee, M., Molloy, S., Moolla, R., Wang, T., Sharps, K., Adame, J.A., Ancellet, G., Apadula, F., Artaxo, P., Barlasina, M., Bogucka, M., Bonasoni, P., Chang, L., Colomb, A., Cuevas, E., Cupeiro, M., Degorska, A., Ding, A., Fröhlich, M., Frolova, M., Gadhavi, H., Gheusi, F., Gilge, S., Gonzalez, M.Y., Gros, V., Hamad, S.H., Helmig, D., Henriques, D., Hermansen, O., Holla, R., Huber, J., Im, U., Jaffe, D.A., Komala, N., Kubistin, D., Lam, K.-S., Laurila, T., Lee, H., Levy, I., Mazzoleni, C., Mazzoleni, L., McClure-Begley, A., Mohamad, M., Murovic, M., Navarro-Comas, M., Nicodim, F., Parrish, D., Read, K.A., Reid, N., Ries, L., Saxena, P., Schwab, J.J., Scorgie, Y., Senik, I., Simmonds, P., Sinha, V., Skorokhod, A., Spain, G., Spangl, W., Spoor, R., Springston, S.R., Steer, K., Steinbacher, M., Suharguniyawan, E., Torre, P., Trickl, T., Weili, L., Weller, R., Xu, X., Xue, L. and Zhiqiang, M., 2017.  Elem Sci Anth, 5, p.58. DOI: 10.1525/elementa.244.

Historic global biomass burning emissions based on merging satellite observations with proxies and fire models (1750–2015). van Marle, M., Kloster, S., Magi, B., Marlon, J., Daniau, A., Field, R., Arneth, A., Forrest, M., Hantson, S., Kehrwald, N., Knorr, W., Lasslop, G., Li, F., Mangeon, S., Yue, C., Kaiser, J., and van der Werf, G. (2017). Geosci. Model Dev., 10:3329–3357.

Regional trend analysis of surface ozone observations from monitoring networks in eastern North America, Europe and East Asia. Chang K-L, Petropavlovskikh I, Cooper OR, Schultz MG, Wang T. Elem Sci Anth. 2017;5:50. DOI: 10.1525/elementa.243.

Sustainable Policy—Key Considerations for Air Quality and Climate Change. (2016). M.L. Melamed, J. Schmale, and E. von Schneidemesser. Current Opinion in Environmental Sustainability. doi:10.1016/j.cosust.2016.12.003.

Arctic air pollution: Challenges and opportunities for the next decade. (2016). Arnold S, Law K, Brock C, Thomas J, Starkweather S, et al.Elementa Science for the Anthropocene, doi: 10.12952/journal.elementa.000104.

Fostering a collaborative atmospheric chemistry research community in the Latin America and Caribbean Region (2016) Marcos Andrade-Flores, Nestor Rojas, Megan L. Melamed, Olga L. Mayol-Bracero, Michel Grutter, Laura Dawidowski, Juan Carlos Antuña-Marrero, Carlos Rudamas, Laura Gallardo, Ruben Mamani-Paco, Maria de Fatima Andrade, and Nicolas Huneeus. Bull. Amer. Met. Soc.

Mexico City hosts a course on remote sensing for Latin Americans. (2016). Grutter, M., J. C. Antuña-Marrero, and C. Rudamas. Eos, 97, doi:10.1029/2016EO051059.

What We Breathe Impacts Our Health: Improving Understanding of the Link between Air Pollution and Health. (2016). J. Jason West, Aaron Cohen, Frank Dentener, et al. Environ. Sci. Technol., 50, 10, doi: 10.1021/acs.est.5b03827.

The international global atmospheric chemistry (IGAC) project: Facilitating atmospheric chemistry research for 25 years (2015) Megan L. Melamed, Paul S. Monks, Allen H. Goldstein, Mark G. Lawrence, Jeff Jennings. Anthropocene, 12, doi: 10.1016/j/ancene.2015.10.001.

Present and Future of Global Atmospheric Chemistry Research in Japan (2015), Tanimoto, H. et al., Review article in the Special Issue “25-yr summary of IGBP-Japan activities”, Chikyukankyo, 20, 151-162.

Interdisciplinary Research Aspects of Open Biomass Burning and its Impact on the Atmosphere Special Issue (2015) Eds. J.W. Kaiser and M. Keywood. Atmos. Env..

A global assessment of precipitation chemistry and deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity and pH, and phosphorus (2014) R. Vet, R.S. Artz, S. Carou, et al., Atmospheric Environment.
*This is a WMO sponsored assessment that includes observations and input from the IGAC Activity DEBITS.

Arctic Air Pollution: New Insights from POLARCAT-IPY (2014). K.S. Law, A. Stohl, et al., Bulletin of the American Meteorology Society.

New Directions: Fundamentals of atmospheric chemistry: Keeping a three-legged stool balanced (2014) J. Abbatt, C. George, M. Melamed, P. Monks, S. Pandis, and Y. Rudich. Atmos. Env.

Bounding the role of black carbon in the climate system: A scientific assessment. Bond, T.C., Doherty, S., Fahey, D.W. & Forster, P., Berntsen, T., DeAngelo, B., Flanner, M., Ghan, S., Kärcher, B., Koch, D., Kinne, S., Kondo, Y, Quinn, P.K., Sarofim, M., Schultz, M.G., Michael, S., Venkataraman, C., Zhang, H., Zhang, S., and Zender, C.S.. (2013). Journal of Geophysical Research: Atmospheres. 118. 5380-5552. 10.1002/jgrd.50171. 

Megacities and Large Urban Agglomerations in the Coastal Zone: Interactions Between Atmosphere, Land, and Marine Ecosystems (2013) von Glasow et al. AMBIO 42:13–28, DOI 10.1007/s13280-012-0343-9.

The Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) Special Issue (2013) Eds. M. Dameris, D. Spracklen, and H. Tost. Atmos. Chem. Phys.

New perspectives on Air-Ice Chemical Interactions (AICI) Special Issue (2013) Eds. V. F. McNeill, E. Wolff, T. Bartels-Rausch, and H. Pfeiffenberger. Atmos. Chem. Phys.

New Directions: GEIA's 2020 vision for better air emissions information (2013) G.J. Frost, P. Middleton, L. Tarrason, C. Granier, et al. Atmos. Env.

Global Air Quality and Climate (2012) Fiore, A.M. et al. Chem. Rev.

TRAGNET Analysis and Synthesis of Trace Gas Fluxes Special Issue (2010) Eds. D. Ojima and A. Mosier. Global Biogeochemical Cycles.

POLARCAT (Polar Study using Aircraft, REmote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport) Special Issue (2009) Eds. A. Stohl, K. Law, J.W. Bottenheim, P. Monks, and P. Quinn. Atmos Chem Phys.

Clean air for megacities (2009)
 Parrish, DD, T Zhu, Science, 326, 674-675.

Atmospheric composition change – global and regional air quality 
(2009) Monks, PS, C Granier, S Fuzzi, A Stohl, ML Williams, H Akimoto, M Amann, A Baklanov, U Baltensperger, I Bey, N Blake, RS Blake, K, Carslaw, OR Cooper, F Dentener, D Fowler, E Fragkou, GJ Frost, S Generoso, P Ginoux, V Grewe, A Guenther, HC Hansson, S Henne, J Hjorth, A Hofzumahaus, H Huntrieser, ISA Isaksen, ME Jenkin, J Kaiser, M Kanakidou, Z Klimont, M Kulmala, P Laj, MG Lawrence, J Lee, C Liousse, M Maione, G McFiggans, A Metzger, A Mieville, N Moussiopoulos, JJ Orlando, CD O'Dowd, PI Palmer, DD Parrish, A Petzold, U Platt, U Pöschl, ASH Prévôt, CE Reeves, S Reimann, Y Rudich, K Sellegri, R Steinbrecher, D Simpson, H ten Brink, J Theloke, GR van der Werf, R Vautard, V Vestreng, Ch Vlachokostas, R von Glasow, Atmos. Env., 43 (33),5268-5350.



AMMA Tropospheric Chemistry and Aerosols Special Issue (2008) Eds. F. Dentener, P. Formenti, C. Reeves, and J. Williams. Atmos Chem Phys.

Air Ice Chemical Interactions (AICI) Special Issue (2007) Eds. P. Shepson, B. Sturges, and E. Wolf. Atmos Chem Phys.

International Consortium for Atmospheric Research on Transport and Transformation (ICARTT): North America to Europe Special Section (2006) Eds. D. Parrish, J. Geophys. Res., 111 (10 - 23).

Intercontinental Transport and Chemical Transformation 2002 (ITCT 2K2) and Pacific Exploration of Asian Continental Emissions (PEACE) Experiments Special Section (2004) Eds. D. Parrish, J. Geophys. Res., 109 (23).

Characterization of Asian Aerosols and Their Radiative Impacts on Climate Special Section (2004) Eds. B. Huebert, T. Bates and P. B. Russell. J. Geophys. Res. 107 (D23) - 109 (D23).

Global Aerosol Climatology Project Special Issue (2002) Eds. M. Mishchenko, J. Penner and D. Anderson. J. Atmos. Sci. 59 (3).

Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) Special Section (2000) Eds. W. Hartley, P. Hobbs and J. Ross. J. Geophys. Res., 105 (D8).

Sixth Scientific Conference of the International Global Atmospheric Chemistry Project (IGAC) Special Issue (2000) Eds. S. Fuzzi, Atmos. Env. 34 (29-30).

ACE-2 Special Issue, Eds. H. Rodhe. Tellus Series B: Chemical and physical meteorology 52B(2), April 2000

Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) Special Section (1999) Eds. P. Russell, P. Hobbs and L. Stowe. J. Geophys. Res., 104 (D2).

Reactive Chlorine Emissions Inventory (RCEI) Special Section (1999) Eds. T. Graedel and W. Keene. J. Geophys. Res., 104 (D7).

Nonmethane Hydrocarbon Intercomparison Experiment (NOMHICE): Task 3 (1999), E. Apel, J. Calvert, T. Gilpin, F. Fehsenfeld, D. Parrish, and W. Lonneman, J. Geophys. Res., 104 (D21) doi: 10.1029/1999JD900793.

Experiment for Regional Sources and Sinks of Oxidants (EXPRESSO) Special Section (1999) Eds. R. Delmas, A. Druilhet and B. Cros. J. Geophys. Res. 104 (D23).

First Aerosol Characterization Experiment (ACE 1) Part 2 Special Section (1999) Eds. T.S. Bates. J. Geophys. Res. 104 (D17).

3-D Global Simulations of Tropospheric CO Distributions – Results of the GIM/IGAC Intercomparison 1997 Exercise (1999) M Kanakidou, F.J. Dentener, G.P. Brasseur, T.K. Berntsen, W.J. Collins, D.A. Hauglustaine, S. Houweling, I.S.A. Isaksen, M. Krol, M.G. Lawrence, J.-F. Muller, N. Poisson, G.J. Roelofs, Y. Wang, and W.M. F. Wauben, Chemosphere - Global Change Sci., 1.

3-D Global Simulations of Tropospheric Chemistry with Focus on Ozone Distributions – Results of the GIM/IGAC Intercomparison Exercise European Commission Report EUR 18842, Office for Official Publications of the European Communities, Luxembourg, 79 pp., 1999.

North Atlantic Regional Experiment II (NARE II) Special Section (1998) Eds. S. A. Penkett, A. Volz-Thomas and D. D. Parrish. J. Geophys. Res., 103 (D11).

Measurements of Ozone by Airbus In-Service Aircraft (MOZAIC) Special Section (1998) Eds. A. Marenco, V. Thouret and P. Nédélec. J. Geophys. Res., 103 (D19).

International Global Atmospheric Chemistry (IGAC) Project’s First Aerosol Characterization Experiment (ACE-1) Special Section (1998) Eds. T. S. Bates, B. J. Huebert and J. L. Gras. J. Geophys. Res., 103 (D13).

Pacific Exploratory Mission (PEM-West B) Special Section (1997) Eds. J. M. Hoell, D. D. Davis and S. C. Liu. J. Geophys. Res., 102 (D23).

Southern Tropical Atlantic Region Experiment (STARE) Special Section (1996) Eds. M. O. Andreae, J. Fishman and J. Lindesay. J. Geophys. Res., 101 (D19).

Pacific Exploratory Mission (PEM-West A) Special Section (1996) Eds. J. M. Hoell, D. D. Davis and S. C. Liu. J. Geophys. Res., 101 (D1)

North Atlantic Regional Experiment (NARE) Special Section (1996) Eds. F. C. Fehsenfeld, M. Trainer and D. D. Parrish. J. Geophys. Res., 101 (D22).

Mauna Loa Observatory Photochemistry Experiment (MLOPEX 2) Special Section (1996) Eds. E. L. Atlas and B. A. Ridley. J. Geophys. Res., 101 (D9).

Atlantic Stratocumulus Experiment/Marine Aerosol and Gas Exchange (ASTEX/MAGE) Special Section (1996) Eds. B. Huebert. J. Geophys. Res., 101 (D2).

Fire of Savannas (Dynamoque et Chimie Atmospherique en Foret Equatorial (FAS, DECAFE 91) Special Issue (1995) Eds. J. P. Lacaux. J. Atmos. Chem., 22 (1-2).

The Nonmethane Hydrocarbon Intercomparison Experiment (NOMHICE): Tasks 1 and 2 (1994), E. Apel, J. Calvert, and F. Fehsenfeld, J. Geophys. Res., 99 (D8), doi: 10.1029/94JD00086.

Polar Sunrise Experiment (PSE) Special Section (1994) Eds. L. A. Barrie, J. W. Bottenheim and W. R. Hart. J. Geophys. Res., 99 (D12).

The Interactive Atmosphere: Global Atmospheric-Biospheric Chemistry (1994) Prinn, R.G. Ambio, 23 (1).

Tropospheric Chemistry of the Arctic Region Special Issue (1993) Eds. A. N. Gruzden and S. A. Sitnov. Tellus Series B, 45 (2).

Tropospheric Chemistry of the Antarctic Region Special Issue (1992) Eds. B. A. Bodhaine and L. A. Barrie. Tellus Series B, 44 (4).

Polarstern Expedition Special Issue (1992) Eds. U. Platt, J. Rudolph, T. Brauers, and G. W. Harris. J. Atmos. Chem., 15 (3-4).

Terrestrial Biosphere Exchange with Global Atmospheric Chemistry. Eds. P. Matson and D. Ojima. IGBP Report No. 13.