Ozone production due to emissions from vegetation burning     

Günter Helas  Jürgen Lobert  Dieter Scharffe  Luise Schäfer  Johann Goldammer  Jean Baudet  Brou Ahoua  Ayité-Lô Ajavon  Jean-Pierre Lacaux  Robert Delmas  Meinrat O. Andreae 《Journal of Atmospheric Chemistry》1995,22(1-2):163-174

Ozone has been observed in elevated concentrations by satellites over areas previously believed to be background. There is meteorological evidence, that these ozone plumes found over the Atlantic Ocean originate from vegetation fires on the African continent.In a previous study (DECAFE-88), we have investigated ozone and assumed precursor compounds over African tropical forest regions. Our measurements revealed large photosmog layers at altitudes from 1.5 to 4 km. Both chemical and meteorological evidence point to savanna fires up to several thousand km upwind as sources.Here we describe ozone mixing ratios observed over western Africa and compare ozone production ratios from different field measurement campaigns related to vegetation burning. We find that air masses containing photosmog ingredients require several days to develop their oxidation potential, similar to what is known from air polluted by emissions from fossil fuel burning. Finally, we estimate the global ozone production due to vegetation fires and conclude that this source is comparable in strength to the stratospheric input.  相似文献   

Potential Impacts of Climate Change on Fire Regimes in the Tropics Based on Magicc and a GISS GCM-Derived Lightning Model     

Johann Georg Goldammer  Colin Price 《Climatic change》1998,39(2-3):273-296

Investigations of the ecological, atmospheric chemical, and climatic impacts of contemporary fires in tropical vegetation have received increasing attention during the last 10 years. Little is known, however, about the impacts of climate changes on tropical vegetation and wildland fires. This paper summarizes the main known interactions of fire, vegetation, and atmosphere. Examples of predictive models on the impacts of climate change on the boreal and temperate zones are given in order to highlight the possible impacts on the tropical forest and savanna biomes and to demonstrate parameters that need to be involved in this process. Response of tropical vegetation to fire is characterized by degradation towards xerophytic and pyrophytic plant communities dominated by grasses and fire-tolerant tree and bush invaders. The potential impacts of climate change on tropical fire regimes are investigated using a GISS GCM-based lightning and fire model and the Model for the Assessment of Greenhouse Gas-Induced Climate Change (MAGICC).  相似文献   

Airborne measurements of savanna fire emissions and the regional distributio of pyrogenic pollutants over Western Africa     

Helas  Günter  Lobert  Jürgen  Scharffe  Dieter  Schäfer  Luise  Goldammer  Johann  Baudet  Jean  Ajavon  Ayité-Lô  Ahoua  Brou  Lacaux  Jean-Pierre  Delmas  Robert  Andreae  Meinrat O. 《Journal of Atmospheric Chemistry》1995,22(1-2):217-239

We measured CO₂, CO, CH₄, H₂, and NO₂ in air masses polluted by savanna fires over Côte d'Ivoire, western Africa. Elevated concentrations of these trace gases were found in fire plumes and also in extensive haze layers. Trace gas mixing ratios ranged as high as 605 ppmv for CO₂, 14.8 ppmv for CO, 2.7 ppmv for CH₄, 4.2 ppmv for H₂, and 25 ppbv for NO₂. We compare our emission ratios to those obtained in previous field and laboratory studies. The emission ratios, expressed as an average and as a range or as an average only, were: dCO/dCO₂ 5.3×10^–2 (3–18×10^–2); dCH₄/dCO 5.3×10^–2; dH₂/dCO 2.4×10^–1 and dNO₂/dCO₂ 1.8×10^–4 (1.5–2.2×10^–4). The values found match those found during similar measurements, though our results point to rather vigorous burning in the savanna of western Africa.  相似文献   

Possibilities and Limitations of Interdisciplinary, User-oriented Research: Experiences from the German Research Network Natural Disasters     

Bruno Merz  Jana Friedrich  Markus Disse  Jochen Schwarz  Johann G. Goldammer  Jochen Wächter 《Natural Hazards》2006,38(1-2):3-20

The German Research Network for Natural Disasters (DFNK) linked 15 partners with scientific expertise in the field of natural hazards. Main objectives were the development and provision of the scientific fundamentals for an advanced risk management of important natural disasters in Germany, i.e., floods, earthquakes, storms and wildland fires. This included risk analyses, the development of information systems for supporting disaster management, and recommendations for risk reduction measures. This paper gives an overview of DFNK and summarises its experiences concerning multidisciplinarity and user-orientation. It illustrates the concept of risk chains, causally linking the different processes from hazard to risk. The step from hazard to risk requires interdisciplinary research teams. The experiences show that integrative concepts allow results not achievable with mono-disciplinary approaches. Integrative approaches pave the way to harmonised safety considerations taking into account the different hazards in a region within a common framework. User-orientation, policy advice and development of operational tools are key issues of disaster research. The experiences of DFNK illustrate the limitations of a research network in bridging the gap between research and application within rather short-term projects. Successful cooperation with users could be established by those activities where, at the beginning of the project, a user was identified who had a strong interest in solving an urgent problem.  相似文献