Natural Variability and Anthropogenic Perturbations of Tropical Atmospheric Chemistry
One of the core projects of the International Geosphere-Biosphere Programme (IGBP) is the International Global Atmospheric Chemistry (IGAC) project. The overall objectives of IGAC Focus 2 are to understand the chemical processing and transport of gases in the tropical atmosphere, and the role of terrestrial biosphere- atmosphere trace gas exchanges in regulating atmospheric composition. Much of the research in this Focus is directed toward understanding the effects of human activities, especially land-use change and land-use intensification, on trace gas fluxes and atmospheric chemistry. Several interrelated Activities are addressing these major objectives.
Note: The follow-up activity “Interdisciplinary Biomass Burning Initiative” (IBBI) was launched in 2012:
Biomass burning has only recently been recognized as a major source of important trace gases and aerosol particles. Through burning, the chemical elements in vegetation are cycled back to the atmosphere and to soils in chemical and physical forms and proportions which make biomass burning an important biogeochemical process. Before the advent of humans, fire was ignited naturally by lightning strikes in dry vegetated regions. Today, however, the process is driven almost exclusively by human activity which includes the burning of forested areas to facilitate land clearing, the burning of harvest debris to maintain cleared land, the extensive burning of natural grasslands and savannas to sustain nomadic agriculture, and the burning of biomass as fuel for cooking and heating.
The emissions from biomass burning represent a large perturbation to global atmospheric chemistry, especially in the tropics. Satellite observations have revealed elevated levels of O3 and CO over vast areas of Central Africa and South America, over the tropical Atlantic, and the Indian Ocean. This is due to biomass burning, which represents a major global source for a number of important gases, including CO2, NO, CO, and CH4, as well as aerosols. The gaseous emissions affect regional O3 concentrations and the oxidative characteristics of the tropical atmosphere. The aerosols affect regional, and possibly global, radiation budgets by their light-scattering effects and by their influence on cloud microphysical processes.
Fire also has both short- and long term effects on trace gas emissions from affected ecosystems which, for instance, in the case of CO2 and N2O, may be more significant than their immediate release during the fire. Fire also alters the long term dynamics of the cycling and storage of elements within terrestrial ecosystems, thereby altering their significance as sources or sinks of various trace gases. Finally, deposition of compounds produced by biomass burning on pristine tropical ecosystems may affect their composition and dynamics.
Due to the paucity and difficulty of measurements in burning regions, and the complexity of the ecosystem and combustion dynamics involved in biomass burning and its subsequent effects, our understanding of trace gas emissions resulting from biomass burning is very limited. The importance of biomass burning is well recognized in IGAC and this Activity, Biomass Burning Experiment: Impact on the Atmosphere and Biosphere (BIBEX), was established to address this phenomenon. It is being carried out by a multi-national science team headed by Meinrat O. Andreae (1990-1998) and Johann G. Goldammer (1998-present), both Max Planck Institute for Chemistry, Germany. It is aimed at quantifying the extent of the temporal and spatial distribution, dynamics, species emissions, and atmospheric consequences of biomass burning.
The first meeting of the BIBEX Coordinating Committee took place in September, 1990, in Chamrousse, France. Additional meetings have been and will be held periodically, often in conjunction with IGAC Symposia or other appropriate scientific meetings. Details can be obtained from the convener. As with all IGAC Activities, BIBEX utilizes and builds on existing international programs with common goals. It has since developed STARE (Southern Tropical Atlantic Regional Experiment) and FIRESCAN (Fire Research Campaign Asia-North) as BIBEX programs, and is contributing to EXPRESSO (EXPeriment for REgional Sources and Sinks of Oxidants) and LBA (Large Scale Biosphere-Atmosphere Experiment in Amazonia). BIBEX will continue to adopt or initiate new programs in the future. In its activities, BIBEX focuses on biomass burning in the tropics, but also considers extratropical fire regions when appropriate. The following figure summarizes present BIBEX efforts.
Fig.1. Regional Fire Research Campaigns in the Decade1990 – 2000
To characterize the production of chemically and radiatively important gases and aerosol species from biomass burning to the global atmosphere.
To assess the consequences of biomass burning on regional and global atmospheric chemistry and climate.
To determine the short- and long term effects of fire on post-fire exchanges of trace gases between terrestrial ecosystems and the atmosphere.
To understand the biogeochemical consequences of atmospheric deposition of products of biomass burning.
Implementation Strategy and the BIBEX Tasks
Our understanding of trace gas emissions resulting from biomass burning is not commensurate with their environmental importance. Too little is known at this time of the geographical distribution of biomass fires, of fire intensities and the relative amounts of flaming and smoldering fires in various ecosystems, of trace gas emission factors, of the chemistry within biomass plumes, and of the impact of biomass burning on ecosystems. The following Tasks have been proposed and developed to address the major gaps in our knowledge on biomass burning.
Editorial note: The BIBEX 2002-2004 program is currently being prepared.
Task 2.3.1: Global Inventories of Biomass Burning
At present, the information available on the spatial and temporal distribution of biomass burning in the tropics is insufficient. Due to population growth, changes in land-use have accelerated over the past decade, particularly in the tropical forest and savanna regions. There is thus an urgent need to obtain reliable and up-to-date global inventories of fire locations and biomass quantities burned for permanent cultivation, for shifting cultivation, and of fires in the humid savannas. Satellite observations during the next decade will afford considerable improvement in our ability to map the geographical distribution and frequency of fires, and will also provide information on their temperatures and spatial extent. They will have to be linked to geographical information systems (GISs) in order to obtain reliable quantitative estimates of fire and emission characteristics. An extensive documentation of fire distribution in South America and Africa is available at the Fire Atlas website.
Emissions to the atmosphere from biomass burning are directly related to the loading characteristics of above-ground biomass. The above-ground carbon loading determines the amount of CO2 and other carbon compounds emitted to the atmosphere. Distinction must be made between flaming and smoldering phases of burning, as the emissions of combustion products are quite different for both phases. Current estimates of above- ground loadings in forests and savannas are uncertain and preclude the compilation of sufficiently accurate global emission inventories. The objectives of this Task are: 1) to construct global inventories of biomass burning, with particular emphasis on establishing spatial and temporal statistics, 2) to forecast future trends in biomass burning, and 3) to quantify the above-ground biomass loadings of diverse ecosystems subjected to biomass burning and their relationship to weather, nutrient status of the soil and land-use patterns (agricultural practices, grazing activities).
Efforts are underway to construct worldwide regional inventories of the areal extent of burning and the quantities of biomass burned both at present and also in the past, as well as the quantities of biomass which potentially can be burned in the relevant terrestrial ecosystems. These inventory data, together with existing and future measurements of the composition and yields of gases and aerosols from burning at representative sites over the globe, are expected to provide the necessary estimates of the contributions of emissions from biomass burning to the global budgets of each species. They will also provide the basis for development of realistic fire dynamics and combustion chemistry theories and models, which are essential to predict future emissions due to biomass burning.
Remote sensing methods provide important means for compiling geographical statistics of fire frequencies, e.g. the AVHRR (Advanced Very High Resolution Radiometer) sensor carried on board the NOAA series of satellites is suitable for studying fires and vegetation characteristics. A limitation of AVHRR is its spatial resolution (1-4 km). This limitation will be significantly reduced in the future by using sensors such as the Earth Observing System/Moderate Resolution Imaging Spectrometer (EOS/MODIS), which has 500 m resolution, and other EOS sensors such as HIRIS (High Resolution Imaging Spectrometer) and MISR (Multi-angle Imaging Spectro-Radiometer). Ground-based data compilations are essential complements to remote sensing efforts. New spaceborne sensors such as the MODIS and the recently launched BIRD satellite of the DLR (launch: 22 October 2001), the FOCUS instrument (designed for the International Space Station, Phase A underway 2001-2002), are dedicated to detect fires, quantify fire effects, and fire emissions. Collaboration with FAO (Food and Agriculture Organization) will be initiated to compile country-by-country biomass burning practices. On-site investigations will be targeted in selected areas (e.g., the savannas of Africa and South America).
In order to overcome critical gaps in global fire documentation the Global Fire Monitoring Center (GFMC) has been established in June 1998 in accordance with
the objectives of IGBP-IGAC-BIBEX (this homepage)
the objectives of the UN International Decade of Natural Disaster Reduction (IDNDR) and its successor arrangement UN International Strategy for Disaster Reduction (ISDR)
the recommendations of the ITTO Guidelines on Fire Management in Tropical Forests, and
the recommendations of various scientific and policy conferences in the field of fire, e.g. the FAO/ECE/ILO Conference “Forest, Fire and Global Change” (Russia 1996)
The GMFC is sponsored by the government of Germany, Ministry of Foreign Affairs, as a German contribution to the ISDR. The fire documentation, information and monitoring system is accessible through the Internet:
The GFMC is established at the Fire Ecology and Biomass Burning Research Group of the Max Planck Institute of Chemistry, Germany. Since the begin of the 1990s the Max Planck Institute has been responsible to design, coordinate, organize and partially implement several international fire research campaigns under the umbrella if the International Geosphere-Biosphere Programme (IGBP). The institute is chairing the scientific steering committee of the fire science component within the IGBP (the Biomass Burning Experiment [BIBEX]) and hosts the BIBEX Secretariat, located at the GFMC.
Following the principles which were developed for a scientific Global Vegetation Fire Information System in the early 1990s, the Global Fire Monitoring Center will document archived and provide real-time or near-real time information related to fire. This will include the interlinking with other national, regional and international information systems.
Task 2.3.2: Chemical Characterization of Biomass Burning Emissions and Plume Chemistry
Biomass burning releases large quantities of reactive compounds to the atmosphere, in particular NOx, hydrocarbons, and CO. Large quantities of soot and organic carbon aerosol are also emitted. Chemical reactions involving NOx and hydrocarbons produce large amounts of O3, consuming the precursors in the process. Aircraft observations of relatively aged plumes from biomass burning have documented an almost total conversion of NOx to less reactive NOy species, and elevated levels of O3. Chemical transformations in fresh plumes appear to regulate the ultimate chemical input from biomass burning into the global atmosphere.
Aircraft measurements of the chemical composition of plumes from biomass burning have been made by several groups in diverse environments. However, these research efforts must be viewed as preliminary. Typically, chemical characterizations have been limited to a few species, and data are lacking for some potentially important species including aerosols. Process models must be developed to describe the chemical transformations occurring in the burns and in the fresh biomass burning plumes.
The objectives of this Task are:
to quantify the gas and aerosol emissions resulting from biomass burning in diverse ecosystems under conditions of flaming and smoldering combustion,
to develop process models describing the composition of emissions as a function of biomass type and environmental variables which integrate models of fire dynamics and combustion chemistry, especially for savanna systems, and
to document and model the reactivity of the chemical species in biomass burning plumes.
This Task will be implemented using several different approaches:
(A) Aircraft Sampling:
The recent advances in aircraft instrumentation technology have improved considerably the detection limits and measurement accuracies for many trace gases. The chemical composition of plumes from biomass in various environments will be studied through repeated aircraft-based sampling programs.
Biomass burning plumes are cooled rapidly as they mix with the local atmosphere, and are then transported with the prevailing winds. The chemical evolution of a plume can be documented by small aircraft through cross-sections of the plume at successive distances from the burned site. Such studies can provide key information for evaluating the rates of chemical transformations within the plumes. The chemical measurements must be supported by ancillary meteorological measurements and photographs allowing documentation of the spread of the plume over time.
(B) Remote sensing Measurements:
Satellite observations providing a global survey of the composition of biomass burning plumes and their dispersal in the global atmosphere will become available by the middle to late 1990s and will be an important contribution to this task. Global mapping of CO and O3 columns will be achieved by the Global Ozone Monitoring Experiment (GOME) and Scanning Imaging Absorption Spectrometer for Atmospheric Chartography/Chemistry (SCIAMACHY) sensor, scheduled for inclusion on the ESA ERS-2 (European Space Agency Remote Sensing Satellite) in 1993-94 and/or later launches. Global mapping of CO will also be available on the EOS-A platform in the late 1990s, using the MOPPITT (Measurement of Pollution in The Troposphere) or TRACER sensors. The sensor TES, planned for launching on the EOS-B platform, will provide horizontal and vertical mapping of a number of trace species including CO, O3, NOx and HNO3.
(C) Combustion Chamber Experiments:
Programs to measure the products of biomass burning in combustion chambers are currently underway in several laboratories. These chamber experiments provide a unique opportunity for measuring emissions of molecular nitrogen (N2) and of short-lived trace gases from biomass burning.
Photochemical models simulating the chemical evolution of biomass plumes will be developed to interpret the aircraft observations. The plume chemistry can be complicated by heterogeneous reactions involving aerosols. Comparison of model results with observations will identify the gaps in the current understanding of photochemical processes in biomass burning plumes. A programme of laboratory kinetic studies will accompany this activity. Chemical models will be developed also to interpret the observations from combustion chambers and to relate them to easily measurable variables such as biomass composition, biomass flammability, oxygen availability, and flame temperatures found in the field.
Task 2.3.3: Short- and Long Term Effects of Fires on Terrestrial Ecosystems
Fire has both short- and long term effects on trace gas exchanges between the biosphere and the atmosphere. Short term changes in fluxes of biogenic trace gases following fire have been reported from many systems. These are driven by changes in nutrient availability, microclimate, and microbial populations. Together, these changes can result in higher fluxes of specific N and C containing trace gases after fire; increases can persist for days to years following fires. In contrast, biogenic emissions of NMHCs may be drastically reduced for periods of a few months or until vegetation is reestablished.
Fire removes large quantities of C, N, and S from burned areas; it leaves most of the other essential elements behind. Fire also affects ecosystem structure and function for long periods of time, especially in forest environments. Consequently, biological productivity in burned sites may eventually become limited by low nitrogen availability, and the storage of carbon and fluxes of N and C containing gases may be reduced in the long term.
The objectives of this Task are: 1) to determine the short- and long term effects of fire on post-fire exchanges of trace gases between terrestrial ecosystems and the atmosphere, and 2) to determine the long term effects of fire on carbon and nitrogen storage and turnover.
The effects of biomass burning on terrestrial ecosystems will be assessed in several key areas that include the tropical forests and pastures, savannas, and boreal forests. Long term post-fire sampling of well characterized sites that differ in fire history will be based on the pattern of nutrient dynamics at particular times post-fire. Field experiments and models will be used to determine, integrate, and extend knowledge of post-fire trace gas exchanges.
On the longer term, a set of experimentally burned plots will be established in tropical savanna and cleared forest regions and the long term effects of fire on the dynamics of C, N, and other nutrient elements, as well as vegetation composition and flammability, will be studied.
Task 2.3.4: Ecological Effects of Deposition of Biomass Burning Products
While the impact of atmospheric O3 on vegetation processes has received attention in the temperate zone, the potential for similar effects has not been studied in the tropics. Levels of O3 comparable to those which reduce photosynthesis in temperate zones occur over much of the tropics during the dry season as a consequence of biomass burning; it is likely that similar or greater effects on photosynthesis, growth, and yields in the tropics could be observed. On the longer term, deposition of anthropogenically fixed nitrogen and other products of biomass burning could alter biogeochemical dynamics in tropical regions. The objective of this Task is to understand the biogeochemical consequences of atmospheric deposition resulting from biomass burning.
Information from measurements of plume dispersion and regional deposition will be used to establish studies of the effects of burning-derived oxidants on pristine tropical ecosystems and agricultural yields. A sampling network will be established across forest-savanna boundaries to address the magnitude of burning-induced transport across biome boundaries.
STARE is an aircraft- and ground-based measurement programme that was initiated in May, 1990, by an ad hoc committee of scientists from Europe, Brazil and the United States, to investigate the sources of trace gases, their atmospheric transport, and the chemical processes in the atmosphere which lead to elevated levels of O3, CO, and other trace gases over the southern tropical Atlantic Ocean. This project was subsequently incorporated into BIBEX at the first meeting of the BIBEX Coordinating Committee in September, 1990, in Chamrousse, France. Three field campaigns have been conducted under STARE. The results from STARE/TRACE-A/SAFARI have been published as a special volume of the Journal of Geophysical Research, a monograph ” Ecological and Atmospheric Effects of Savanna Fires in Southern Africa.” and in the pages of the proceedings of the Chapman Conference on Biomass Burning and Global Change (1995) (see BIBEX publications). Additional papers on the results from STARE are still in various stages of publication.
Some of the main conclusions from STARE are:
Biomass burning in the tropics is a major source of trace gases and aerosols, with wide-ranging effects on atmospheric composition.
Fires in South America and Africa release precursor gases (NOx, VOC) which lead to the formation of huge amounts of ozone in the troposphere over the Atlantic Ocean.
Convective processes have a pronounced influence on the redistribution of these pollutants and enhance the production of ozone by addition of lightning-generated NOx.
The emission factors of trace gases and aerosols from savanna fires are now quite well known as a result of STARE and some other campaigns. However, large uncertainties persist with regard to the amounts of biomass burned as a function of locality and time.
Transport and chemistry near the Equator-Atlantic (TRACE-A)
(TRACE-A) covered the western portion of the STARE region. The main objective of TRACE-A, conducted in August-October, 1992, was to investigate the chemical composition, transport, and chemistry of the atmosphere over the southern tropical Atlantic Ocean and the adjacent South American continent. The research focused on understanding the seasonal enhancement in O3 that has been observed over the tropical Atlantic Ocean and that is most likely caused by widespread burning of vegetation (forest conversion, savanna fires) in South America and Southern Africa. It also investigated the potential contribution of land-use changes in both continents on the observed levels of other trace gases such as CH4 and N2O. TRACE-A activities involved chemical and meteorological measurements in Brazil (ground and aircraft component, jointly by Brazilian and American research groups), ozonesonde launches in the Congo Republic and on Ascension Island, and an aircraft component (NASA DC-8) spanning the South Atlantic. This was coordinated with Brazilian and African aircraft components.
Southern Africa Fire-Atmosphere Research Initiative (SAFARI)
Southern African Fire-Atmospheric Research Initiative (SAFARI-92) covered primarily the African portion of the STARE region. The research objectives of SAFARI were similar to those of TRACE-A, but also included the investigation of the ecological role of fire in African savannas and the study of trace gas emissions from burned soils. SAFARI-92 involved ground and airborne chemical and meteorological measurements in the source or near-source regions of South Africa, and was carried out primarily as a cooperative international campaign. It also involved international participation in measuring emissions from savanna fires and other biomass burning as well as remote sensing of fires by satellites. The source related measurements were complemented by regional airborne and ground-based studies on pyrogenic pollutant distribution and transport.
The findings confirm the hypothesis that a large portion of the southern hemispheric atmosphere is subjected to dramatic seasonal changes influenced by vegetation fires. The transport meteorology of fire emissions has been clarified by SAFARI/TRACE-A. The implications of the STARE programme findings are manifold in regard to land use systems and sustainable development. A special issue of the Journal of Geophysical Research (American Geophysical Union) was published in October 1996 (1). On 811 pages, the special issue contains 60 articles written by 178 authors and co-authors, representing some 300 to 400 scientific and technical staff involved in the project. The results of this research programme are an impressing result of an unprecedentedly large international, interdisciplinary and intercontinental fire experiment.
The consequences of the research on the SAFARI (=African) side of STARE are highlighted in a synthesis monograph which is dedicated to the ecology of fire in African savannas (corresponding to the results of SAFARI) (2).
TRACE-A and SAFARI Special Issue. Journal of Geophysical Research 101, No.D19, 23,519-24,330.
van Wilgen, B., M.O.Andreae, J.G. Goldammer, and J. Lindesay (eds.) 1997. Fire in Southern African savannas. Ecological and atmospheric perspectives. The University of Witwatersrand Press, 256 pp.
Southern African Atmosphere Research Initiative (SA’ARI-94)
SA’ARI – 94 was planned as a follow-up of the SAFARI- 92 (Southern African Fire-Atmosphere Research Initiative) experiment, which focused on assessing the influences of vegetation fires on the atmosphere over Africa. Only sparse information exists, however, on the composition of trace gases in the troposphere in this region outside the burning season. SA’ARI – 94 was therefore planned as an activity without the “F(ire)”. It was anticipated that local burning would be negligible up to the beginning of June, so the experiment was planned for May 1994. The results show, however, that May was already too late. Whereas SAFARI – 92 was a truly interdisciplinary exercise, SAARI – 94 was planned as a small project with the goal of obtaining general information on tropospheric air composition over southern Africa outside the traditional burning season.
Comparative analysis revealed that spring trace gas and aerosol values were elevated above those for autumn. These elevated values are attributed to biomass burning transport and direct impact typical for the fire season. High autumn trace gas and aerosol values in the southeast region of the subcontinent indicate industrial emissions as the primary source in absence of fires. In the southeast trace gas and aerosol values during spring are of a similar magnitude to autumn values, resulting in a low seasonal variability for this area.
Comparison of 5°-latitudinal bands indicate that gradients of trace components are related to the temporal and spatial distribution of biomass burning and emissions from industry. During the fire season (SH spring) trace gas values are elevated equatorward in accordance with the fire maximum of the tropics. Trajectory analysis and source inventories indicated that industrial sources are significant in the southeastern part of the study area during the autumn season.
Results of this work are published or are in the process of preparation for publication. The abstracts are given Titles are given in the list below.
EXPeriment for REgional Sources and Sinks of Oxidants (EXPRESSO)
Tropical biomes are the most dynamic, yet most poorly understood biomes on Earth. Tropical forests are being cleared at a rate of about 1% per year. Biomass burning, ubiquitous in African savannas, exerts a dominant influence on ecology and atmospheric chemistry. Biogenic fluxes of reactive or radiatively active trace gases are concentrated in tropical land areas and are strongly influenced by land-use change and biomass burning. Future human population increase is projected to be higher in tropical areas than in any other region and will accelerate changes in land-use. The interplay of global change, climate change, biogeochemical processes, population increases and resource limitations are likely to affect more people in the tropics than anywhere else.
An international experiment, EXPRESSO, was designed to investigate tropical biogeochemistry. EXPRESSO is taking place in the Central African Republic (CAR) and the Republic of Congo. The goals of EXPRESSO are:
to better quantify the exchange fluxes of reactive trace gases and aerosols between the biosphere and the atmosphere in the tropics;
to analyze chemical interactions between the savanna and the tropical forest;
to isolate the roles of photochemical and meteorological processes;
to characterize the effects of ecological processes on trace gas fluxes;
to assess the impact of these tropical processes and land-use change on the global atmosphere.
Initially, two field intensives were planned for a 1996-1997 time frame. One was planned for the wet season of the CAR savanna, and one for the dry, biomass burning season. The dry season experiment took place from November to December 1996.
The field campaigns include: 1) ground-based field studies in the savanna and in the tropical forest to determine the fluxes of important carbon and nitrogen-containing trace gases, 2) aircraft studies to define the chemical and meteorological climatology of the study region, 3) remote sensing studies to define the location and extent of biomass burning and to aid in vegetation characterization, and 4) modeling efforts for a hierarchy of models which operate on scales ranging from micro-scale processes which occur in soil and leaves, to coupled regional/global models of atmospheric chemistry and dynamics.
AFARI-97 Field Campaign in Kenya Implemented in September/October 1997
The African Fire-Atmosphere Research Initiative (AFARI) is a regional expansion and continuation of the Southern African Fire-Atmosphere Research Initiative (SAFARI) which was implemented in its main campaign phase in 1992.
Whereas the atmospheric chemical importance of savanna and grassland fires in Southern Africa seems to be well understood, no information is available on atmospheric effects of fires occurring in East African savannas. Remotely sensed data reveal that extensive fires occur in the savanna areas of East Africa. Consequently, it was decided to turn research attention to that part of the world. A special focus of the AFARI-97 project was the investigation of the relationship between aerosol production and associated CO and CO2 formation during prescribed experimental burns and wildfires of opportunity. The ecological value of these data is that aerosols formed during vegetation fires are assumed to be of significant importance for the radiation budget of the atmosphere on a global scale. The results will be used to improve the understanding of the aerosol sources and be added to the IGBP-IGAC and IGBP-DIS databases, i.e. they will be freely available to interested research parties.
Aerial view of a AFARI-97 experimental burning plot at Lewa Downs, Kenya, September 1997.
AFARI-97 was conducted in two sites in Kenya in late September and early October 1997 (Lewa Downs Ranch in the Isiolo district immediately north of Mount Kenya and Hopcraft Ranch on the Athi Kapiti Plains 40 km south of Nairobi). The size of experimental burns ranged between 50-200 hectares. Ground measurements included standard botanical and fuel inventories (before and after the burns), fire behavior, and meteorological data. The airborne component concentrated on aerosol sampling. Most of the experimental burns were coordinated with satellite measurements for validation purposes. The fires were described in detail on the ground and from small aircraft during the overpass of the Advanced Very High-Resolution Radiometer (AVHRR) on the NOAA weather satellite. In addition, it was tried to validate the capabilities of the Space Shuttle Earth Observation System. The STS-86 mission, however, passed the burning sites at early morning hours and could not be coordinated with the experiments.
Institutions participating in AFARI-97
Max Planck Institute for Chemistry – Germany
University Nairobi – Kenya
National Academy of Sciences – Kenya
University Fort Hare – South Africa
Canadian Forest Service, Forest Fire Research – Canada
Division of Life Science, King’s College London – United Kingdom
Atmospheric Sciences Division, NASA Langley Research Center – U.S.A.
Department of Environmental Sciences, University of Virginia – U.S.A.
Principle contacts for AFARI-97:
Günter Helas / Johann G. Goldammer
Max Planck Institute for Chemistry
PO Box 3060
D – 55020 Mainz
e-mail: email@example.com and Winston S. W. Trollope
Dept. Livestock & Pasture Science
University of Fort Hare
38 Durban Street, Private Bag X1314
Fort Beaufort 5720
Republic of South Africa
The Zambian International Biomass Burning Emissions Experiment (ZIBBEE)
The ZIBBEE experiment was organized in cooperation with the US Forest Service Fire Chemistry Laboratory, the Zambian Meteorology Department and NASA’s AERONET and EOS IDS program with the primary objectives to quantify the aerosol and trace gas fluxes from the Miombo woodlands of southern Africa. Embedded within this study are objectives to quantify the consumption of biomass (carbon) from biomass burning, validation of aerosol retrievals from various satellite sensors, and direct radiative forcing by biomass burning aerosols.
The main focus was to measure the carbon flux from the massive amount of burning taking place to the east of the Western Province of Zambia, estimate direct radiative forcing due to smoke from biomass burning, and validate satellite aerosol retrievals. The measurement approach established a 400 km transect of ground based sun photometers orthogonal to the prevailing easterlies and to fly an in situ aerosol and trace gas sampling system in the transect to establish a 2-D measurement plain during a variety of meteorological and burning conditions. The ground-based measurement network remained in operation for the duration of the burning season. Appropriate satellite, meteorological and ancillary ground based data were collected.
Four cimel automatic sun-sky scanning spectral radiometers were maintained at Sesheke, Senanga, Mongu and Zambezi. Solar flux measurements were established at Mongu, Zambezi, and Senanga.
Total column ozone and AOT from hand-held microtops instruments were established at Mongu, temporary, and mobile sites.
Low volume particulate mass samples were collected on Teflon filters with a six-hour replacement schedule.
An additional site for automatic cimel measurements and microtops was established midway between Senanga and Mongu on flight days.
Automatic weather stations were established the previous year at Senanga, in Mongu and Zambezi by the USFS.
A 20 site network of 2-band hand-held sunphotometers was established at and between the four principal sites.
A micropulse lidar (MPL) was deployed at Mongu for the continuous monitoring of the aerosol profile.
An airborne instrument package which included in situ measurements of ozone, aerosol filter samples, canister samples, WS, WD, relative humidity, CO, CO2, backscatter and location information was loaded onto a Cessna-206 and other small aircraft.
AVHRR imagery will be used to estimate radiative forcing, fire events, radiative properties of aerosols, aerosol optical depths and cloud droplet size distributions.
Participating institutions of ZIBBEE
United States Forest Service, Intermountain Fire Sciences Laboratory, Missoula – U.S.A
Zambian Meteorological Office, Mongu – Zambia
NASA Goddard Space Flight Center, Greenbelt – U.S.A
University of Virginia
University of Alabama, Huntsville – U.S.A.
Principle contact for ZIBBEE:
Darold E. Ward
Intermountain Fire Sciences Laboratory
US Forest Service
P.O. Box 8089
U.S.A. – Missoula, MT 59801
A comparison between emissions from every day domestic fire practices and wildfires
Vegetation fires are well-known phenomena in tropical regions. Today, 70-90% of these fires are believed to be of anthropogenic origin: most often for hunting, surrogates for pesticides and insecticides, modification of land use and simply inattentiveness. Lightning is the predominant natural trigger for vegetation fires. Spectacular events quite often evolve from the combustion of this biomass, but they rarely happen more than once a year.
Yet there is another use for this biomass, which has been reported to provide about 14% of the world’s primary energy. Biomass burning supplies nearly 35% of the energy to about half of the global population. In Africa, the biomass contribution alone to the total energy use typically ranges from 80-90% in poor, 55-65% in middle and 30-40% in high-income groups. So these domestic combustion processes necessarily have to take place every day.
To assess emissions from the fire practices a few groups have investigated in both consumption of biofuel and related emissions. Like the group around J.-P. Lacaux, Toulouse, France, we have studied patterns of biofuel use and made measurements of on emissions of CO2, CO, NO, and occasionally organic compounds and aerosols in the lodgings of rural and urban Zimbabwe, Nigeria and Kenya.
A tentative global analysis shows that the source strength of domestic biomass burning is on the order of 1500 Tg CO2-C yr-1, 140 Tg CO-C yr-1, and 2.5 Tg NO-N yr-1. This represents contributions of about 7 to 20% to the global budgets of these gases.
Results of this work are published or are in the process of preparation for publication. The abstracts of the six main research components are given below:
For further publications on biofuel burning: Please visit the BIBEX publication list!
Fire Research Campaign Asia–North (FIRESCAN)
For the Eurasian region, the “Fire Research Campaign Asia-North” (FIRESCAN) began in 1992. FIRESCAN addresses the role of fire in boreal ecosystems and the consequences for the global atmosphere and climate (Goldammer and Furyaev 1996, FIRESCAN Science Team 1996).
IGBP-IGAC-BIBEX closely cooperates with the research programmes mentioned in the following paragraphs. One of the major expected impacts of all programmes is to stimulate exchange in research and development between the countries formerly divided by the Cold War (Goldammer and Furyaev 1995).
IGBP Northern Eurasia Study
Additional fire experiments will be conducted jointly with scientists collaborating in the IGBP Northern Eurasia Study. It will be a joint effort of scientists representing several IGBP Core Projects, the Biospheric Aspects of the Hydrological Cycle (BAHC), International Global Atmospheric Chemistry (IGAC), and Global Change and Terrestrial Ecosystems (GCTE) Projects. The unifying theme of the IGBP Northern Eurasia Study is the terrestrial carbon cycle and its controlling factors, and the study’s overall most important objective is to determine how these will change under the rapidly changing environmental conditions projected under global change (Steffen and Shvidenko 1996). The IGBP Northern Eurasia Study will consist of an integrated set of experimental and observational studies at a number of scales, modeling and aggregation activities, and supporting databases and GIS capabilities. The major elements are transects and network sites, water, energy, and carbon flux study, and detailed studies of disturbance regimes.
Aerial view of the FIRESCAN International Bor Forest Island Fire Experiment, Krasnoyarsk Region, Russia (1993)
The fire component of the IGBP Northern Eurasia Study will have four components: (i) fire manipulations at individual forest sites; (ii) a series of campaigns based on aerial and spaceborne research platforms; (iii) the construction of a fire database, relating the frequency, extent, and intensity of fires to vegetation and climatic conditions for present and historical conditions; and (iv) development of aggregated models of forest fire frequency and extent, responsive to global change variables.
Goldammer, J.G., and V.V. Furyaev 1995. Global change, the boreal forest, and fire: Search for new strategies in science policies and research mechanisms. Science Policy: New Mechanisms for Scientific Collaboration between East and West (V.A. Koptyug and J. Klerkx, eds.), 45-61. NATO ASI Series 4, Science and Technology Policy Vol.1. Kluwer Academic Publishers, Dordrecht-Boston-London, 256 p.
Goldammer, J.G., and V.V. Furyaev (eds.) 1996. Fire in ecosystems of boreal Eurasia. Kluwer Academic Publ., Dordrecht, 528 pp.
Steffen, W.L., and A.Z. Shvidenko (eds.). 1996. The IGBP Northern Eurasia Study: Prospectus for Integrated Global Change Research. The International Geosphere-Biosphere Program: A Study of Global Change. International Council of Scientific Unions (ICSU), IGBP Stockholm <English 95 p., Russian 108 p.>.
Goldammer, J.G. (ed.) 2013. Prescribed Burning in Russia and Neighbouring Temperate-Boreal Eurasia. A publication of the Global Fire Monitoring Center (GFMC). Kessel Publishing House, 326 p. (ISBN 978-3-941300-71-2) (http://www.forestrybooks.com/)
The South East Asian Fire Experiment (SEAFIRE):
Draft Structure of a Science Plan for the ASEAN Region
The South East Asian Fire Experiment (SEAFIRE) is a research activity in the planning and preparation phase and will be conducted under the scheme of the International Geosphere-Biosphere Programme (IGBP). The International Global Atmospheric Chemistry (IGAC) Project is a core project of IGBP. One of the activities of IGAC Focus 2 (Natural Variability and Anthropogenic Perturbations of the Tropical Atmospheric Chemistry) investigates the impact of biomass burning on the atmosphere and biosphere (Biomass Burning Experiment [BIBEX]). SEAFIRE will establish the fire research component within the Integrated SARCS/IGBP/IHDP/WCRP Study on Land-use Change in SE Asia.
SEAFIRE will explore the ecological impacts of fire in land use (fires used in forest conversion and shifting cultivation, grassland and seasonally dry [monsoon] forests) and the characteristics, the regional and global transport mechanisms and the atmospheric chemical impacts of pyrogenic emissions. Biogenic and marine sources of trace gases and aerosols will be considered, as well as technogenic sources (fossil-fuel burning, secondary chemical products). Special emphasis will be laid on inter-annual climate variability (ENSO vs. non-ENSO) and the role of the “Warm Pool” in the global distribution of fire products.
Questions to be asked in the context of SEAFIRE and other research programmes within the ASEAN region:
Are human use of fire and fire regimes undergoing changes?
Are ecological and atmospheric chemical impacts of fire contributing to local/regional/global climate changes?
Will regional fire use / fire regimes undergo changes in a regionally changed climate?
How can existing information and questions to be asked integrated into an interdisciplinary regional study (e.g. transects)?
SEAFIRE’s operational approach is twofold. First, SEAFIRE will build on existing data and research results. It also intends to collaborate with research institutions (government, universities) of ASEAN nations which are working in fields relevant to SEAFIRE objectives (e.g., meteorology, remote sensing, air pollution monitoring). Second, a set of small and large field research campaigns are planned to address the open questions which are largely in the field of emissions chemistry and transport. Such field research will be conducted on the ground, and on air-, space- and ship-borne platforms.
Editorial Remark: SEAFIRE so far has not been realized to a lack of intra-regional and international interest and synergies.
The Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA)
Despite widespread concern and increased international efforts at conservation, the world’s tropical forests continue to disappear. Of vital importance in developing sustainable management and exploitation systems for tropical forests are the questions as to how far human intervention affects the forest’s basic capacities to renew themselves and how to safeguard the basic ecological processes such as biological productivity and nutrient and water cycling. Altered cycles of water, energy, carbon, and nutrients, resulting from the changes in Amazonia vegetation cover, are expected to have climatic and environmental consequences at local, regional and global scales. To understand these consequences and to mitigate their negative effects, enhanced knowledge is needed of the functioning of both the existing natural forest systems as well as systems which have already been converted to various other forms of land use or secondary regrowth.
Summary of LBA
The Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) is an international research initiative led by Brazil. LBA is designed to create the new knowledge needed to understand the climatological, ecological, biogeochemical, and hydrological functioning of Amazonia, the impact of land use change on these functions, and the interactions between Amazonia and the Earth system. LBA is centered around two key questions that will be addressed through multi-disciplinary research, integrating studies in the physical, chemical, biological, and human sciences:
How does Amazonia currently function as a regional entity?
How will changes in land use and climate affect the biological, chemical and physical functions of Amazonia, including the sustainability of development in the region and the influence of Amazonia on global climate?
In LBA, the emphasis is given to observations and analyses which will enlarge the knowledge base for Amazonia in six general areas: Physical Climate, Carbon Storage and Exchange, Biogeochemistry, Atmospheric Chemistry, Hydrology, and Land Use and Land Cover. The program is designed to address major issues raised by the Climate Convention. It will help provide the basis for sustainable land use in Amazonia, using data and analysis to define the present state of the system and its response to observed perturbations, complemented by modeling to provide insight to possible changes in the future.
The Atmospheric Chemistry Component will provide a foundation of knowledge to determine the exchange of greenhouse gases, oxidants, and aerosols between Amazonia and the global atmosphere, to understand the relevant processes, and to assess the related implications of rapid development in the region. The observations will be used to address the following key questions:
What are the biosphere-atmosphere fluxes of greenhouse gases, oxidants, and aerosols (including their precursors) over the range of ecosystems in Amazonia?
What are the net export fluxes of greenhouse gases, oxidants, and aerosols from Amazonia to the global atmosphere?
The experimental plan for the atmospheric chemistry component of LBA combines long-term ground-based measurements and intensive two-month aircraft campaigns. The ground-based components have the following objective:
To determine the concentrations of key reactive and greenhouse gases and aerosols at key surface sites in Amazonia, and define the primary influences on those concentrations”
In order to address this objective, the suite of measurements should include a range of indicator species for biomass burning (e.g. CO, acetylene, methyl chloride) and industrial activity (CFCs, other halocarbons), along with key reactive species (NOx, O3), biogenic reactive hydrocarbons (isoprene), and greenhouse gases (CO2, CH4, N2O). An important feature of the measurements will be direct observation of FLUXES for species where possible, to provide information on the role of Amazonian forests and agriculture.
A network of 2-6 ground-based sites will be established for long-term observations of atmospheric chemistry and biosphere-atmosphere exchange. Concentrations and fluxes of CO2, CH4, N2O, O3, CO, NOx, non-methane hydrocarbons, reactive sulfur gases, and aerosol particles will be measured at the smallest scales using chamber methods and at landscape-scale using towers. Flux measurements will emphasize direct (e.g. eddy correlation or eddy accumulation) observations for accessible species (CO2, O3, NOx, NOy) with similarity approaches for other gases (e.g. N2O, CO, non-methane hydrocarbons, sulfur gases) designed to gain leverage from, and be calibrated by, the direct flux measurements. Measurements will continue for several years to define episodic, seasonal, and interannual variations of trace species, and measurements should be as continuous as possible, to observe variations and to define seasonal changes.
The sites will be strategically located along ecological and meteorological gradients, and in most cases will coincide with flux towers installed for the carbon and biogeochemistry components of LBA.
A background site is desirable at a coastal location (e.g. Fortaleza) where air from the tropical Atlantic can be routinely measured. Observations at this site will help characterize the marine end-member for air entering the Amazon basin. Flux measurements are not needed at this site, but data on CO2, CH4, N2O, O3, CO, NOx, NOy, and other medium- and long-lived species are needed.
Two aircraft campaigns are currently in the planning stage. The first campaign, CLAIRE-1 (Cooperative LBA AIrborne Regional Experiment) has been conducted during February/March 1998 using Dutch and Brazilian aircraft. Since this campaign will fall in the wet season of the southern hemisphere, a relatively smoke-free atmosphere is anticipated. The second campaign, CLAIRE-2, took place around October 1999 and will study the impact of smoke on the Amazonian troposphere and its export from the region. (See also the LBA-CLAIRE website on Surinam, located at Utrecht University, Netherlands)
The ground-based observations, and the aircraft campaigns to be undertaken in LBA offer only limited spatial and temporal coverage. Application of 3-D chemical tracer models will be essential to assimilate the measurements, in order to quantify fluxes within and across the boundaries of the Amazon Basin. These models will use assimilated meteorological observations (e.g., from a 4DDA model) and include a chemical simulation capability. The observed biosphere-atmosphere fluxes and data from the marine station will help provide the required boundary conditions for this analysis. Simulation of species concentrations measured aboard the aircraft will serve to test and refine the models. In addition to their importance for post-campaign data interpretation, the models will play a key role in pre-campaign planning by identifying locations most suitable for siting the observations.
Update on the Southern African Regional Science Initiative – SAFARI 2000
SAFARI 2000 continues to progress in its development. With the successful completion of the NASA EOS SAFARI 2000 workshop, regional and international participants met at the SAFARI 2000 Regional Implementation Workshop in Gaborone, Botswana during 26-30 July 1999.
Those individuals interested in finding out more about SAFARI 2000, in general, or the Regional Implementation Workshop, in particular, are encouraged to visit our website: http://safari.gecp.virginia.edu. The SAFARI 2000 Executive Summary, as well as the NASA EOS SAFARI 2000 Workshop Summary, are attached below.
SAFARI 2000 Executive Summary
The Southern African Regional Science Initiative – SAFARI 2000 – is an international, collaborative science initiative aimed at developing an integrated understanding of selected aspects of the southern African earth-atmosphere-human system. The foundations of the study were laid during June and July 1998 at a series of stakeholder workshops involving scientists from southern Africa, the United States, and Europe. The goal of SAFARI 2000 is to identify and understand the key linkages among the physical, chemical, biological and anthropogenic processes underpinning the functioning of the biogeophysical and biogeochemical systems of southern Africa.
This initiative will explore and study the linkages between land-atmosphere processes, principally the biogenic, pyrogenic and anthropogenic emissions occurring in the region, their transport and transformations in the atmosphere, their influence on regional climate and meteorology, and their eventual deposition and its effects on the functioning of the ecosystems of the region. To this end, SAFARI 2000 will
exploit the synergy between remote sensing, modeling, airborne sampling, and ground-based studies;
use the semi-closed sub-continental anticyclonic circulation system as the mechanism linking the biological, physical and chemical components of the regional ecosystems; and,
combine the expertise and knowledge base of regional and international scientists.
SAFARI 2000 follows on the success and builds upon the scientific legacy of the Southern African Fire-Atmosphere Research Initiative in 1992 (SAFARI-92). SAFARI-92 showed a) that with a concerted effort it is feasible to quantify and validate regional emissions, and b) that our understanding of the impacts of these various emissions needed further study. As a result, at the core of SAFARI 2000 is an experiment to quantify and validate these regional emissions, thereby providing the basis for the study of the impacts of those emissions on the biogeophysical system.
SAFARI 2000 is a coalition of related regional and global environmental change research efforts being undertaken or planned by the African, U.S. and European science communities for the period 1999 to 2001 in southern Africa. They include initiatives that are already funded and underway; planned initiatives for which funding is being sought; and some that are still being formulated. SAFARI 2000 encompasses the following science elements with contributions from both ground-based and airborne activities: land processes; land use and land cover change; terrestrial ecology; aerosols and trace-gas chemistry and transport; surface radiation; cloud characterization and radiative effects; and hydrology. The ground and airborne measurements will be complemented by remote sensing observations from the new generation of earth observation satellites, such as the NASA TERRA platform scheduled for launch in July 1999, Landsat 7 and TRMM. In turn, the earth and atmosphere based observations of SAFARI 2000 will help validate the remotely sensed satellite observations on a regional scale.
These linked, short and long term field campaigns will measure and model biological, soil, atmospheric and radiation processes, using the existing ground-based and upper air monitoring networks, as well as airborne and remote sensing activities, for additional leverage. The international regional science networks developed within the region under the auspices of IGBP and START will participate in the initiative and will be the mechanism for broader African scientific involvement.
SAFARI 2000 will be conducted over a three-year period starting in 1999 with three intensive ground and flying field campaigns:
August-September 1999 dry season: identify and quantify major dry-season sources of emissions including those from biomass burning, land use, and industry. February-March 2000 wet season: identify and quantify major wet season sources of emissions (e.g. CH4 from wetlands and NMHC from plants). August-September 2000 dry season: track the movement, transformations, and deposition of dry-season emissions from biomass burning and other sources.
Each successive campaign will increase the level of international collaboration. Ground-based efforts will be coordinated to maximize overlap in the observations and for maximum logistical efficiency. Intensive meteorological and remote sensing measurements will support the campaigns throughout.
The integrated and synthesized products of SAFARI 2000 will be available during 2001 and will contribute to improving the scientific basis of the International Panel on Climate Change (IPCC) assessments for the region. The results will also contribute to the development of improved policies and practices for the management of regional air quality. Regional scientists will benefit through heightened recognition, enhanced capacity, and the transfer of technology. This, in turn, should help in formulating appropriate policies and responses to manifestations of climate change and to international treaties relating to global environmental issues. The policy and societal relevance of the scientific results of SAFARI 2000 will be addressed through an ongoing series of workshops to be held in conjunction with various regional networks. One such workshop, the Policy Dialogue Workshop on Ecological Impacts of Trans-boundary Air Pollution in Southern Africa, organized by the Air Pollution Impacts Network for Africa (APINA), has already been held. Others will follow.
SAFARI 2000 has an internal and external data sharing policy. Information will be disseminated regionally and internationally via the internet as well as through the distribution of CD-ROMS. The results from SAFARI 2000 will also provide a knowledge base to support the assessment of global change on a regional scale.
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1990-2000 Construction of a global land cover map using existing data from remote sensors such as NDVI, SPOT, SIMMR, and TM (Thematic Mapper). Such maps are now available at a number of sites, e.g. the USGS Global Land Cover Characterization site, are being refined further.
1990-1995 Combustion chamber experiments to characterize biomass burning products under different combustion conditions, and for different biomass types.
1990-2000 Aircraft measurements of the composition of biomass burning plumes, with focus on documenting the chemical evolution of individual plumes.
1990-2000 Field studies of biomass burning plumes, focusing on detailed characteristics of the plume composition.
1991-2000 Development of photochemical models to interpret the chemical evolution of the plumes observed from aircraft.
1992-2000 Measurements of short- and long term exchanges of trace gases following fire and their regulation in a range of ecosystems.
1991-2000 Select and establish long term experimental sites; initiate and maintain burning treatments.
1991-2000 Development of models of combustion chemistry to interpret the combustion chamber measurements. Development of integrated biomass combustion models that simulate fire spreading and plume composition on the basis of observable variables such as biomass composition, biomass structure, flame temperature, meteorological parameters, and topography.
1996-2000 Initiation of measurements of oxidant effects on productivity and yields of tropical crops.
1996-2000 Development of an experimental programme to study the effects of N and acidic deposition on the functioning of tropical ecosystems.
1994-2000 Design and execution of coordinated studies to evaluate models.
1998- Beginning of the EOS programme; use of data from MODIS, HIRIS, etc., to construct global land cover maps with 0.5-1 km resolution.