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27 results on '"Lacaux, J.P."'

6. Acid wet deposition in the Tropics : two case studies using DEBITS measurements.Acid rain

Author

Galy-Lacaux, Corinne, Lacaux, J.P., Pienaar, K., Mphepya, J., Sigha, L., Laboratoire d'aérologie (LAERO), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]
Abstract

12-17 juin 2005

Published
2005

7. Acid wet deposition in the tropics: two case studies using DEBITS measurements

Author

Lacaux, J.P., Tathy, J.P., Sigha, L., Laboratoire d'aérologie (LAERO), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]
Published
2003

8. Dry and Wet atmospheric nitrogen deposition in Africa

Author

Galy-Lacaux, Corinne, Al Ourabi, H., Galloway, J., Lacaux, J.P., Mphepya, J., Pienaar, K., Pont, V., Sigha, L., Yoboue, V., Laboratoire d'aérologie (LAERO), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]
Abstract

This work is part of the IDAF* (IGAC/DEBITS/AFrica) programme which started in 1995 with the establishment of 10 measurement sites representative of major African ecosystems. The objectives of the programme are to study dry and wet deposition of important trace species and more generally the biogeochemical cycles of key nutrients. In this way, the IDAF activity is based on high quality measurements of atmospheric chemical data (gaseous, precipitation and aerosols chemical composition) on the basis of a multi-year monitoring. In this paper, our objective is to present the first estimation of the atmospheric nitrogen deposition budget in Africa based on experimental measurements. To estimate atmospheric nitrogen deposition, including both wet and dry processes, we compiled the IDAF nitrogen data (rain, particles and gases) obtained from the network for three consecutive years: 1998, 1999 and 2000. In western and central Africa, we studied a transect going from dry savanna (Niger and Mali) to humid savanna (Ivory Coast and Central Republic of Africa) and forest (Congo and Cameroon). In South Africa, two IDAF very different sites were chosen to be representative on one hand of a rural (semi-arid savanna) and on the other hand of an industrialized site. Presenting the different components of the nitrogen atmospheric deposition on these sites, i.e, dry deposition in gaseous (NO2, NH3, HNO3) and particulate forms (pNH4+, pNO3-) associated with wet deposition (NH4+, NO3-), this study allows us to give the relative contribution of dry and wet deposition processes to the total nitrogen deposition. The nitrogen atmospheric deposition presented for all the IDAF sites of the african continent range from 8 to 19 kgN.ha-1.yr-1. Sites from dry savanna in South Africa and West Africa have similar values (around 8-9 kgN.ha-1.yr-1 ) which are found in the lower part of the range. Wet zones from savanna and forests give values in the upper range (15 to 19 kgN.ha-1.yr-1). The Amersfoort site, representative of an anthropogenically modified savanna gives values also in the upper range (15 kgN.ha-1.yr-1). Moreover, this study indicates that dry deposition in all the ecosystems dominates and represents about 60-70 percent of the total nitrogen atmospheric deposition (except Amersfoort). These new datasets have led to estimate for the first time the nitrogen budget over the African continent. It is worth noting that the estimated range is similar to modelled ones (Galloway and Cowling, 2002; Rodhe et al, 2002). *IGAC/DEBITS/Africa: International Global Atmospheric Chemistry/ DEposition of Biogeochemically Important Trace Species/Africa

Published
2003

9. DEBITS: past, present and future

Author

Lacaux, J.P., Artaxo, P., Laboratoire d'aérologie (LAERO), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]
Published
2003

11. Biosphere–atmosphere interactions

Author

Brasseur, G.P., Prinn, R.G., Pszenny, A.A.P., Scholes, M.C., Matrai, P.A., Andreae, M.O., Smith, K.A., Manning, M.R., Artaxo, P., Barrie, L.A., Bates, T.S., Butler, J.H., Ciccioli, P., Cieslik, S.A., Delmas, R.J., Dentener, F.J., Duce, R.A., Erickson III, D.J., Galbally, I.E., Guenther, A.B., Jaenicke, R., Jähne, B., Kettle, A.J., Kiene, R.P., Lacaux, J.P., Liss, P.S., Malin, G., Matson, P., Mosier, A.R., Neue, Heinz-Ulrich, Paerl, H.W., Platt, U.F., Quinn, P.K., Seiler, W., Weiss, R.F., Brasseur, G.P., Prinn, R.G., Pszenny, A.A.P., Scholes, M.C., Matrai, P.A., Andreae, M.O., Smith, K.A., Manning, M.R., Artaxo, P., Barrie, L.A., Bates, T.S., Butler, J.H., Ciccioli, P., Cieslik, S.A., Delmas, R.J., Dentener, F.J., Duce, R.A., Erickson III, D.J., Galbally, I.E., Guenther, A.B., Jaenicke, R., Jähne, B., Kettle, A.J., Kiene, R.P., Lacaux, J.P., Liss, P.S., Malin, G., Matson, P., Mosier, A.R., Neue, Heinz-Ulrich, Paerl, H.W., Platt, U.F., Quinn, P.K., Seiler, W., and Weiss, R.F.

Abstract

The contemporary atmosphere was created as a result of biological activity some two billion years ago. To this day, its natural composition is supported and modified, mostly through biological processes of trace gas production and destruction, while also involving physical and chemical degradation processes. The biosphere has a major influence on present environmental conditions, both on a regional and global scale. One of the bestdocumented and most important indicators of global change is the progressive increase of a number of trace gases in the atmosphere, among them carbon dioxide (CO2) , methane (CH4) , and nitrous oxide (N2O), all of which are of biospheric origin. There is considerable uncertainty, however, regarding the processes that determine the concentration and distribution of trace gases and aerosols in the atmosphere and the causes and consequences of atmospheric change (Andreae and Schimel 1989). To improve our understanding IGAC created an environment for multi-disciplinary collaboration among biologists,chemists, and atmospheric scientists. This was essential to develop analytical methods, to characterise ecosystems, to investigate physiological controls, to develop and validate micrometeorological theory, and to design and develop diagnostic and predictive models (Matson and Ojima 1990).

Published
2003

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