GCOS Essential Climate Variables (ECV)
Terrestial
ECV T12 Above Ground Biomass

Biomass plays two major roles in the climate system: a) photosynthesis withdraws CO₂ from the atmosphere and stores it as biomass; and b) quantity of biomass consumed by fire affects emissions of CO₂ and of other trace gases and aerosols. Estimates of biomass change (due to land use and management practices or to natural processes) provide a direct measurement of carbon sequestration or loss and can help to validate carbon-cycle models. (from the FAO/GTOS web site). Data sets below are referenced on page 11 of the ECV T12 Biomass - Assessment of the Status of the Development of the Standards for the Terrestial Essential Climate Variables (ECV), Version 10, May 25, 20099 (GTOS-67) document. More at ECV T12 Biomass FAO/GTOS web page.

Introduction: Changes in land cover are important aspects of global environmental change, with implications for ecosystems, biogeochemical fluxes and global climate. Land cover change affects climate through a range of factors from albedo to emissions of greenhouse gases from the burning of biomass. Deforestation inter alia increases the amount of carbon dioxide (CO₂) and other trace gases in the atmosphere. When a forest is cut and burned to establish cropland and pastures, the stored carbon joins with oxygen and is released into the atmosphere as CO₂. The IPCC notes that about three-quarters of the anthropogenic emissions of CO₂ to the atmosphere during the past 20 years were due to fossil fuel burning. The rest was predominantly due to land use change, especially deforestation. In 2005, a number of developing countries proposed to incorporate deforestation prevention into the Kyoto Protocol, in part through an emissions trading system. The initiative, known as REDD, (Reducing Emissions from Deforestation in Developing countries) would allow developing countries to sell emissions savings from forest conservation. Developed countries would buy the savings to credit against their own emissions targets. IGOS has set up an Integrated Global Carbon Observation (IGCO) Theme (report available from www.igospartners.org ) to develop a flexible, robust strategy for international global carbon observations over the next decade. A key component of IGCO is terrestrial carbon observations aimed at the determination of terrestrial carbon sources and sinks with increasing accuracy and spatial resolution. The IPCC has highlighted an improved understanding of carbon dynamics as vital in tackling one of the biggest environmental problems facing humanity. The IGCO work will be an essential input to the implementation of the United Nations Framework Convention on Climate Change (UNFCCC), particularly on the role of natural sinks in meeting targets under the UNFCCC Kyoto Protocol. Satellite observations allow scientists to map land cover and the dynamics of fire disturbance, and track two key elements of Earth’s vegetation – the ‘Leaf Area Index’ (LAI) and the ‘Fraction of absorbed Photo-synthetically Active Radiation’ (FAPAR). LAI is defined as the one-sided green leaf area per unit ground area in broadleaf canopies, or as the projected needle leaf area per ground unit in needle canopies. FAPAR is the fraction of photosynthetically active radiation absorbed by vegetation canopies. Both LAI and FAPAR are data necessary for understanding how Sunlight interacts with the Earth’s vegetated surfaces. (from the CEOS web site)

Satellite Observations: Multiple types of satellite observations are used in agricultural applications. Space imagery provides information which can be used to monitor quotas and to examine and assess crop characteristics and planting practice. Information on crop condition, for example, may also be used for irrigation management. In addition, data may be used to generate yield forecasts, which in turn may be used to optimise the planning of storage, transport and processing facilities. Classification and seasonal monitoring of vegetation types on a global basis allow the modelling of primary production – the growth of vegetation that is the base of the food chain – which is of great value in monitoring global food security. A number of radiometers provide measurements of vegetation cover, including the ATSR series, AVHRR/3, MODIS, MERIS, SEVIRI and Vegetation. These instruments are helping production of global maps of surface vegetation for modelling of the exchange of trace gases, water and energy between vegetation and the atmosphere. Multi-directional and polarimetric instruments (such as MISR and POLDER) will provide more insights into corrections of land surface images for atmospheric scattering and absorption, as well as Sun-sensor geometry, allowing better calculation of vegetation properties. Synthetic aperture radars (SARs) are used extensively to monitor deforestation and surface hydrological states and processes. The ability of SARs to penetrate cloud cover and dense plant canopies makes them particularly valuable in rainforest and high-latitude boreal forest studies. Instruments such as ASAR, SAR (RADARSAT), and PALSAR provide data for such applications as agriculture, forestry, land cover classification, hydrology and cartography. CEOS and GCOS have concluded that many of the Essential Climate Variables related to vegetation and supported from space will require reprocessing of the moderate resolution historical record (in particular AVHRR) to be of greater value for climate purposes, and appropriate actions have been defined, including the development of enhanced calibration and validation schemes which guarantee long-term stability and consistency over different temporal and spatial scales. Research topics like scaling, and the development of ‘community radiative transfer models’ integrated into sophisticated assimilation schemes, are of paramount importance for an integrated approach. (Satellite Missions) (from the CEOS web site)

Data, Product, Metadata and Information Access

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