International Geosphere-Biosphere Programme Research Articles

Elevated CO(2) studies: past, present and future.

Increasing concentrations of atmospheric CO(2) are predicted to impact both current and future ecosystems. Elevated CO(2) is also predicted to affect biological processes at many levels of organization. In this overview, we summarize the responses of plants to elevated CO(2) including primary physiological and molecular responses, growth and reproductive responses, effects on plant-plant competition and interactions with other organisms, evolutionary responses, and effects at the ecosystem level. The objectives of this paper are to: (a) overview studies in this issue that were presented at a 1997 meeting entitled "Critical Assessment of the Response of Forest Ecosystems to Elevated Atmospheric Carbon Dioxide," which was sponsored by the Global Change and Terrestrial Ecosystems (GCTE) group of the International Geosphere Biosphere Program (IGBP), (b) review areas of recent progress in CO(2) research, (c) generalize patterns arising from past research, and (d) list critical areas of research for the future.

Detection of Snow Cover Using Millimeter-Wave Imaging Radiometer (MIR) Data

Millimeter-wave Imaging Radiometer (MIR) data, collected from a NASA ER-2 flight over the Great Lakes region and New England in February 1997, are used to identify snow cover. Data at 89 GHz, 150 GHz, and 220 GHz are compared with the Moderate Resolution Imaging Spectroradiometer (MODIS) snow cover product. Additional data sets used in this analysis are the International Geosphere Biosphere Programme (IGBP) land cover classification and the MODIS cloud cover mask. Results show that for cloud-free scenes, the MIR data are well related to the snow and vegetation cover. Under cloudy conditions the MODIS snow mapping algorithm, which uses visible and near-infrared data, is unable to detect snow cover. However, the surface cover is still clearly discernible in the MIR images. It is suggested that high frequency microwave data may be used to supplement the MODIS, or other visible and near-infrared derived snow cover products, during cloudy conditions. The development of snow cover algorithms combining future Earth Observing System (EOS) microwave, visible, and infrared data are discussed.

Polar biogeochemistry and ecosystem feedback mechanisms in a changing environment

The following ten papers are based on presentations made in the sessions on Terrestrial systems and feedbacks on climate change (session 3) and Biogeochemical cycles in the Arctic and Antarctic (session 6). The issues addressed in these sessions all dealt with research questions identified as of highest priority in several programmes under the International Geosphere-Biosphere Programme (IGBP) such as GCTE, BAHC, IGAC, WOCE and JGOFS.

MERIS potential for coastal zone applications

The Medium Resolution Imaging Spectrometer (MERIS) will be flown on the Envisat mission in 1999 and will provide the user community with a unique instrument for monitoring important water quality parameters in coastal waters. The instrument will be of special interest for coastal zone research projects such as the International Geosphere Biosphere Program (IGBP), Land Ocean Interactions in the Coastal Zone (LOICZ) and for environmental impact monitoring, assessment and management programmes. MERIS characteristics include nine spectral channels (out of 15) covering the visible spectral range (410-705nm) which are optimized to the radiance level of water surfaces. Within this range there are bands dedicated to mapping concentrations of suspended particulate matter, phytoplankton, gelbstoff (or coloured dissolved organic matter) and bands for determining sunlight-stimulated fluorescence of phytoplankton chlorophyll. Its spatial resolution of 300m and revisit period of 3 days are well suited to the observation of most of the phenomena which are of interest for coastal water quality research and management. New algorithms will have to be developed for computing the different water constituents from the observations and for atmospheric correction of turbid waters. Examples of applications, for which the design of MERIS is optimized, are presented.

Strategy for a Fire Module in Dynamic Global Vegetation Models

Disturbance plays a major role in shaping and maintaining many of the Earth'sterrestrial ecosystems. In fact, many ecosystems depend on fire for theirvery existence. Global Change is expected to result in changed distributionof current ecosystems, changed composition of those ecosystems, and increation of new ecosystems. The International Geosphere Biosphere Program(IGBP), through the Core Projects Biospheric Aspects of the HydrologicalCycle, International Global Atmospheric Chemistry, Global Change andTerrestrial Ecosystems and International Global Atmospheric Chemistry,Biomass Burning Working Group, recognized that disturbances need to beincluded in the modeling efforts of each project. Disturbance from fire, landuse and other factors may be as important as climate change in shaping futurelandscapes (Weber and Flannigan 1998). Three main themes were recognized:impact of disturbance on carbon pools, vegetation change, and feedbacks to theatmosphere. In June 1998, a workshop was held in Potsdam, Germany to developa strategy to introduce disturbance into dynamic global vegetation models.This strategy was based on the fact that vegetation burning influencesatmospheric chemistry, that feedbacks of energy, water and trace gases tothe atmosphere are influenced by vegetation, and that changes in thecomposition of ecosystems have direct impact on the carbon pool, onbiodiversity, and on health and productivity of the land. Disturbanceincludes fire, insect, disease, drought and flooding, land conversion,land use, air pollution, and introduction of exotic species. While it willbe necessary to ultimately include all disturbances, the Potsdam workshoplimited itself to fire. This strategy is based on the fact that there areno process driven models for all disturbances, and that fire has a numberof reliable models with which to begin the process of introducing disturbanceinto dynamic global vegetation models. While this workshop limited itself tofire, a great deal of consideration was given to the fact that the modelshell must be able to include other disturbances in the future. As a result,the strategy was to focus on a hazard function which would lead to effectsof disturbance. The hazard function is basically a probability statement ofrisk of effects. This approach seems equally valid for all forms ofdisturbance.

中国土地利用構造と一般チューネン＝リカードモデル

Land use phenomena make up a important aspect of ‘environmental system’. LUCC (Land Use/Cover Change) is the joint core project of IGBP (International Geosphere-Biosphere Programme) and IHDP (International Human Dimensions Programme) under the international scheme of ICSU (International Council for Science). LU/GEC (Land Use for Global Environmental Conservation) is the largest LUCC-related project in Japan by NIES aiming at land use prediction models for Asia-Pacific region.The GT (Generalized Thunen)-model (小長谷1997a, b, 1998, Konagaya1997, 1998, 1999a, b, c) is the extension of traditional normative Thiinen model, the exact fundamental theory of land market, to be able to explain the aggregated land use ratios. This new model successfully give a exact theoretical interpretation to the intuitive picture of ‘movement of land use frontier’ such as deforestation or desertification, and enables us to predict the land use change in the future.小長谷・大坪・スンスン (1998『環境システム研究26』) predicts 2025 land use of Jawa and Kalimantan, and Konagaya (1999a, b), 小長谷・大坪 (1998『地球環境シンポジウム6』) analysed the land use of Sumatra with fairly good explanatory powers around R2=0.8.Today the regions with rapid economic growth and environmental destruction concentrate on China proper, thus, effective land use models on China are needed urgently. The Chinese land has a larger scale compared to one island region in South-East Asian countries, various physical conditions are necessary to be incorporated. Because the GT-model stated above based mainly on economic conditions and influences from cities (urban driving force variables), a newly extended model: GTR (Generalized Thiinen-Ricardo)-model integrating the urban driving force variables with the micro physical conditions in each site (on-site variables) is needed.This study analyzes and predicts the Chinese land use by the GTR-model. Southern China has been the center of agricultural production until now. However, the GTR-model predicts that urbanization and industrialization in the south region will drive agricultural land use to the north, making a drastic change in large land use structure of China in 2025.

The fruit of the Second International Geosphere-Biosphere Programme (IGBP) Congress

The fruit of the Second International Geosphere-Biosphere Programme (IGBP) Congress

地球圏-生物圏国際協同研究計画 (IGBP) の促進について (勧告)

地球圏-生物圏国際協同研究計画 (IGBP) の促進について (勧告)

Biospheric Aspects of the Hydrological Cycle

The Core Project Biospheric Aspects of the Hydrological Cycle (BAHC) of the International Geosphere Biosphere Programme (IGBP) addresses the biospheric aspects of the hydrological cycle through experiments and modelling of energy, water, carbon dioxide and sediment fluxes in the soil– vegetation–atmosphere system at a variety of spatial and temporal scales. Active regulation of water, energy and carbon dioxide fluxes by the vegetation make it an important factor in regulating the Earth’s hydrological cycle and in the formation of the climate. Consequently, human induced conversion of vegetation cover is an important driver for climate change. A number of recent studies, discussed in this paper, emphasise the importance of the terrestrial biosphere for the climate system. Initially, these studies demonstrate the influence of the land surface on tropical weather and climate, revealing the mechanisms, acting at various scales, that connect increasing temperatures and decreasing rainfall to large-scale deforestation and other forms of land degradation. More recently, the significance of the land surface processes for water cycle and for weather and climate in temperate and boreal zones was demonstrated. In addition the terrestrial biosphere plays a significant role in the carbon dioxide fluxes and in global carbon balance. Recent work suggests that many ecosystems both in the tropics and in temperate zones may act as a substantial sink for carbon dioxide, though the temporal variability of this sink strength is yet unclear. Further, carbon dioxide uptake and evaporation by vegetation are intrinsically coupled, leading to links and feedbacks between land surface and climate that are hardly explored yet. Earth’s vegetation cover and its changes owing to human impact have a profound influence on a lateral redistribution of water and transported constituents, such as nutrients and sediments, and acts therefore as an important moderator of Earth’s biogeochemical cycles. In the BAHC science programme, the importance of studying the influence of climate and human activities on mobilisation and river-borne transport of constituents is explicitly articulated. The terrestrial water and associated material cycles are studied as highly dynamic in space and time, and reflect a complex interplay among climatic forcing, topography, land cover and vegetation dynamics. Despite a large progress in our understanding of how the terrestrial biosphere interacts with Earth’s and climate system and with the terrestrial part of its hydrological cycle, a number of basic issues still remain unresolved. Limited to the scope of BAHC, the paper briefly assesses the present status and identifies the most important outstanding issues, which require further research. Two, arguably most important outstanding issues are identified: a limited understanding of natural variability, especially with respect to seasonal to inter-annual cycles, and of a complex ecosystem behaviour resulting from multiple feedbacks and multiple coupled biogeochemical cycles within the overall climate system. This leads to two major challenges for the future science agenda related to global change research. First, there is a need for a strong multidisciplinary integration of research efforts in both modelling and experiments, the latter extending to inter-annual timescales. Second, the ever increasing complexity in characterisation and modelling of the climate system, which is mainly owing to incorporation of the biosphere’s and human feedbacks, may call for a new approach in global change impact studies. Methodologies need to be developed to identify risks to, and vulnerability of environmental systems, taking into account all important interactions between atmospheric, ecological and hydrological processes at relevant scales. With respect to the influence of climate and human activities on mobilisation and river-borne transport of constituents, the main issues for the future are related to declining availability and quality of ground data for quantity and quality of water discharge. Such assessments as presented in this paper, in combination with community wide science evaluation, have lead to an update of the science agenda for BAHC, a summary of which is provided in the appendix.

Integrating research on ecohydrology and land use change with land use management

One objective of the International Geosphere–Biosphere Programme is to provide a scientific basis for sustainable development policies. Land use change and ecohydrology are important components of this scientific basis, but predicting change is difficult because of the scale and complexity of the interactions between non-linear ecohydrological and socio-economic processes at different spatial and temporal scales. A systems framework, the Ecosystem Approach, has been developed to conceptualize these interactions for the purpose of providing information for sustainable development policy. The Ecosystem Approach combines the dynamics of the Holling figure-eight model—a conceptual model of dynamics that stresses discontinuous change and destruction as an internal property of the system—and the properties of self-organizing systems with the socio political aspects of decision making. The Ecosystem Approach highlights the problems of managing change in complex systems when that change may involve unpredictable shifts to a different attractor. Although there are methods available to detect the occurrence of such shifts, both detection and modelling are complicated by the presence of semi-stable attractors. When a model or an ecosystem is on a semi-stable attractor, it may appear to remain stable for an extended period prior to changing as a consequence of inherent instabilities. When the shift to a new attractor occurs, it is quite sudden and unpredictable. A technical discussion on prediction under conditions of semi-stability and chaos is included because it enhances our understanding of the role of surprise in ecosystems, as well as the utility of simulation models. The principles of the Ecosystem Approach are derived from the theoretical discussion and an example of a land use policy in the Huron Natural Area in south-western Ontario. These principles provide a clear role for scientific research, and particularly simulation modelling, within the larger context of policy and land use management. Copyright © 1998 John Wiley & Sons, Ltd.

Global land cover classifications at 8 km spatial resolution: The use of training data derived from Landsat imagery in decision tree classifiers

This paper reports a study which aims to (i) develop methodologies for global land cover classifications that are objective, reproducible and feasible to implement as new satellite data become available in the future and (ii) provide a global land cover classification product based on the National Aeronautics and Space Administration/National Oceanic and Atmospheric Administration Pathfinder Land (PAL) data that can be used in global change research. The spatial resolution for the land cover classification is 8 km, intermediate between our previously published coarse one degree by one degree spatial resolution and the 1 km global land cover product being developed under the auspices of the International Geosphere Biosphere Program. We first derive a global network of training sites from Landsat imagery, using 156 Landsat scenes mostly from the Multispectral Scanner System, to identify over 9000 pixels in the PAL data where we have high confidence that the labelled cover type occurs. We then use the training data to test a number of metrics that describe the temporal dynamics of vegetation over an annual cycle for potential use as input variables to a global land cover classification. The tested metrics are based on: (i) the ratio between surface temperature and Normalized Difference Vegetation Index (NDVI); (ii) seasonal metrics derived from the NDVI temporal profile, such as length of growing season; (iii) a rule-based approach that determines cover type through a series of hierarchical trees based on surface temperature and NDVI values; and (iv) annual mean, maximum, minimum and amplitude values for all optical and thermal channels in the Advanced Very High Resolution Radiometer (AVHRR) (PAL) data. Highest mean class accuracies from a decision tree classifier were obtained using the annual mean, maximum, minimum, and amplitude values for all AVHRR bands. Finally, we apply these metrics to 1984 PAL data at 8 km resolution to derive a global land cover classification product using a decision tree classifier. The classification has an overall accuracy between 81.4 and 90.3%. The Landsat images used for deriving the training data and the methodology for classification of AVHRR data at 8km resolution can also be applied to 1 km AVHRR data and, in the future, Moderate Resolution Imaging Spectroradiometer (MODIS) data at 250 and 500m resolution. Digital versions of the land cover dataset and detailed documentation can be found on the World Wide Web at http://www.geog.umd.edu/landcover/8km-map.html.

The IGBP-DIS global 1km land cover data set, DISCover: First results

The International Geosphere-Biosphere Programme Data and Information System (IGBP-DIS) is co-ordinating the development of global land data sets from Advanced Very High Resolution Radiometer (AVHRR) data. The first is a 1 km spatial resolution land cover product 'DISCover', based on monthly Normalized Difference Vegetation Index composites from 1992 and 1993. DISCover is a 17 class land cover dataset based on the science requirements of IGBP elements. Mapping uses unsupervised classification with post-classification refinement using ancillary data. Draft Africa, North America and South America products are now available for peer review.

Applications of the U.S. Geological Survey's global land cover product

The U.S. Geological Survey (USGS), in partnership with several international agencies and universities, has produced a global land cover characteristics database. The land cover data were created using multitemporal analysis of advanced very high resolution radiometer satellite images in conjunction with other existing geographic data. A translation table permits the conversion of the land cover classes into several conventional land cover schemes that are used by ecosystem modelers, climate modelers, land management agencies, and other user groups. The alternative classification schemes include Global Ecosystems, the Biosphere Atmosphere Transfer Scheme, the Simple Biosphere, the USGS Anderson Level 2, and the International Geosphere Biosphere Programme. The distribution system for these data is through the World Wide Web (the web site address is: http://edcwww.cr.usgs.gov/landdaac/glcc/glcc.html) or by magnetic media upon special request The availability of the data over the World Wide Web, in conjunction with the flexible database structure, allows easy data access to a wide range of users. The web site contains a user registration form that allows analysis of the diverse applications of large-area land cover data. Currently, applications are divided among mapping (20 percent), conservation (30 percent), and modeling (35 percent).

The International Geosphere Biosphere Programme Data and Information System global land cover data set (DISCover)

The International Geosphere Biosphere Programme Data and Information System (IGBP-DIS), through the mapping expertise of the U.S. Geological Survey and the European Commission's Joint Research Centre, recently guided the completion of a 1-km resolution global land cover data set from advanced very high resolution radiometer (AVHRR) data. The 1-km resolution land cover product, “DISCover,” was based on monthly normalized difference vegetation index composites from 1992 and 1993. The development of DISCover was coordinated by the IGBP-DIS Land Cover Working Group as part of the IGBP-DIS Focus 1 activity. DISCover is a 17-class land cover data set based on the scientific requirements of IGBP elements. The mapping used unsupervised classification and postclassification refinement using ancillary data. The development of this data set was motivated by the need for global land cover data with higher spatial resolution, unproved temporal specificity, and known classification accuracy. The completed DISCover data set will soon be validated to determine the accuracy of the global classification.

News

News

An Overview of the Implications of Global Change for Natural and Managed Terrestrial Ecosystems

Global change is the net effect of individual and interactive effects of changes in land use, atmospheric composition, biological diversity, and climate. A synthesis of the past six years' activities of the Global Change and Terrestrial Ecosystems project of the IGBP (International Geosphere-Biosphere Programme) deals with global change effects as ecosystem responses and living with global change. Ecosystem responses are considered in terms of changes in function and vegetation composition/structure. Field experiments of elevated CO 2 effects on aboveground biomass show, on average, a positive effect on biomass, ranging from -20% to +80%. Some early predictions of CO 2 effects (C 3 vs. C 4 plants, N-fixers, C:N in litter) are not generally supported, and it is necessary to consider the interactive effects of changes in CO 2 , temperature, and nitrogen. Dynamic global vegetation models involving transient changes show that biomes will not shift as intact entities. Significant changes in vegetation, especially in high latitudes, are likely over the next century, and changes in disturbance regimes will be most important. Based on forecast changes in land use, vegetation structure, and ecosystem physiology, the terrestrial biosphere will probably become a source rather than a sink for carbon over the next century.

The Southern Tropical Atlantic Region Experiment (STARE): Transport and Atmospheric Chemistry near the Equator‐Atlantic (TRACE A) and Southern African Fire‐Atmosphere Research Initiative (SAFARI): An introduction

In November 1988 some 50 atmospheric scientists met at Dookie College, a small campus in the agricultural lands of Victoria, Australia, to map out the scientific goals of the International Global Atmospheric Chemistry (IGAC) Program, which was to become one of the first operational Core Projects of the International Geosphere‐Biosphere Program (IGBP). They identified the tropical regions as one of the priority areas for future international, coordinated research in atmospheric chemistry because of the vast biological activity in the tropics, with a correspondingly large potential for biogenic emissions, and the rapidly growing human populations and resulting land use change in these regions. In view of the prominent role that biomass burning plays in the tropics as a source of atmospheric pollutants and of the important ecological functions of vegetation fires in the tropics, the scientists at Dookie created the Biomass Burning Experiment (BIBEX) with the goals of characterizing the fluxes of gases and aerosols from biomass burning to the global atmosphere and assessing the consequences of pyrogenic emissions on chemical and physical climate.The southern tropical Atlantic region, defined here as the region containing the Amazon basin, the tropical South Atlantic, and southern Africa, was the obvious first focus of research for this project. Large tropical forest and savanna fires had been known to occur here every year. In addition, observations from satellites and from the space shuttle had shown high levels of tropospheric ozone and carbon monoxide to be present over this region every year in the August‐to‐October period. Results from previous campaigns (ABLE 2A, CITE 3, DECAFE 88) also suggested a widespread impact of vegetation fires on both continents on the trace gas and aerosol content of the troposphere in this region.

RECONSIDERATION OF SOME PROBLEMS IN THE STUDY OF PAGES

PAGES is a core project of the International Geosphere-Biosphere Programme(IGBP).Through the organization of coordinated national and international scientific efforts,many great achievements about Past climatic and environmental changes have been obtained.This paper is intended to reconsider some problems found in the study of the PAGES including inevitable and unexpected abrupt climatic changes,certain and uncertain climatic events,simple and complicated processes of climatic variation to arouse the attention and discussion of paleoscientist.

Soil moisture: A critical focus for global change studies

The scientific and human dimensions of global change have many overlapping themes which offer a focus on processes occurring at the continental surface. Soil moisture is of critical importance to the physical processes governing energy and water exchanges at the land/air boundary. Soil moisture controls the extent to which plants can exploit sunlight in photosynthesis and the effectiveness with which agriculture, forestry and freshwater resources can be developed. The importance of the soil moisture to many, diverse communities has resulted in a very large collection of numerical models all of which simulate soil moisture. This paper outlines why and how a series of soil moisture simulation intercomparisons were conducted in a one-year exercise jointly sponsored by the International Geosphere Biosphere Programme and the World Climate Research Programme.

Biomass estimation using satellite remote sensing data—An investigation on possible approaches for natural forest

Vegetation type and its biomass are considered important components affecting biosphere-atmosphere interactions. The measurements of biomass per unit area and productivity have been set as one of the goals for International Geosphere-Biosphere Programme (IGBP). Ground assessment of biomass, however, has been found insufficient to present spatial extent of the biomass. The present study suggests approaches for using satellite remote sensing data for regional biomass mapping in Madhav National Park (MP). The stratified random sampling in the homogeneous vegetation strata mapped using satellite remote sensing has been effectively utilized to extrapolate the sample point biomass observations in the first approach.