ANNEX 6: SATELLITE DATA REQUIREMENTS ANALYSIS

Part 1: Definitions of Applications

(Note: the assigned numbers are for use in the tables of specifications. They do not imply ranking or priorities)

1. Ecosystem productivity

2. Sustainable land use

3. Hydrological resources

4. GHG trend

5. Biodiversity and ecosystem health

6. Climate trend assessment

7. Hazard mitigation

8. Transport services

9. Coastal zone management

10. Climate modeling

11. Improved operational prediction

12. BGC cycling

Ecosystem Productivity and Sustainability (short title: Ecosystem Productivity)

Includes both terrestrial and marine ecosystems. For terrestrial ecosystems it covers: 1) the productivity of terrestrial ecosystems defined in terms of biomass increase over a time interval; and 2) sustainability, described as the ability of the ecosystems to maintain the functions and processes of growth, development, and renewal characteristic of that ecosystem type at the present time. Together, these measures reflect the ability of the ecosystem to remain viable over the long term.

Land use and sustainable development planning (short title: Sustainable land use).

Characterization of the present land use, its sustainabilty, and the potential for land development of the types of use that can be sustained over time.

Hydrological resources assessment (short title: Hydrological resources)

Use of G3OS data for the inventory and assessment of the terrestrial hydrological resources. Includes issues of water quantity and quality, seasonal and interannual variability or trend, natural (soil moisture, wetlands) and artificial (reservoirs) sources, and availability for various types of use. Both surface and ground water resources are included.

Greenhouse gas trend assessment (short title: GHG trend)

Evaluating and quantifying the role of terrestrial ecosystems in the cycle of GHGs and its change over time. The emphasis is on the natural sources and sinks of carbon dioxide, nitrogen oxides, and other gases which interact with (vegetation for carbon uptake or release, etc.); and on processes that are likely to change in response to human activities or to a changing climate.

Biodiversity and ecosystem health

Includes both terrestrial and marine ecosystems. For terrestrial ecosystems it refers to the diversity of the ecosystem at the gene, species and landscape levels (with emphasis on the last two), and to the status of the ecosystem in comparison with a similar fully-functioning, vigorous ecosystem.

Climate trend assessment

Evaluation of the change of climate through its effects on the terrestrial ecosystems. Uses the record of cryospheric, hydrologic, and biospheric processes or phenomena.

Part 2: Definitions of Variables

(Note: these definitions are intended for use with the database of satellite data requirements)

Albedo

Definition to be provided by AOPC

Biogeochemical transport from land to oceans

The transport of elements such as N, C, and P from land to oceans via the rivers or subsurface pathways along the shoreline.

Biomass-above ground

Organic material constituting the plant canopy above the soil.

Biomass-below ground

Organic material constituting plants below the soil surface, mostly in roots.

Peak leaf biomass of nitrogen-fixing plants

The highest leaf mass of nitrogen-fixing plants during the growing season.

Carbon dioxide flux (CO₂)

Definition to be provided by AOPC

Dissolved C, N, and P in water (rivers and lakes)

Concentration of carbon, nitrogen and phosphorus in the fresh water (lakes and rivers).

Dry deposition of nitrate and sulfate

The rate of deposition of nitrate and sulfate from the atmosphere into the terrestrial ecosystems.

Emissions of CO₂, NO_X and SO_X from combustion of fossil fuels

The emission of gases due to combustion of fossil fuels.

Evapotranspiration

The loss from the plants (transpiration) or soil/water surfaces to the atmosphere.

Fertilizer use

The amount of fertilizer used, mostly in agricultural production. Should be specified annually on a national or sub-national basis.

Fire area and impact

The area where the above ground biomass was fully or partly burned by an episodic fire event. Also indicates the intensity of the burn and the form of the carbon released.

Firn temperature

Temperature of the firn, usually measured in boreholes of ice sheets or glaciers etc.

Glaciers and ice caps

Change in the ice thickness, glacierized area, and length of glaciers or ice caps.

Glacier inventory

Identification and mapping the spatial extent of the present glaciers.

Glacier length

The length of a glacier from starting point to the terminus (melting line).

Glaciers mass balance

The difference in the mass of a glacier between the mass gained by snow accumulation and that lost by snow ablation.

Ground water storage fluxes.

The change in the volume of ground water over the observation period.

Ice sheet mass balance

The difference between the mass gained by snow accumulation and that lost by snow ablation and calving activity.

Ice sheet geometry.

The surface topography (3-D shape) of the ice sheet, both in the interior and at the margins.

Lake and river freeze-up/break-up

The timing (dates) of the annual freeze-up and break-up of ice in lakes and rivers.

Land cover

The composition of the land surface, described by assigning contiguous parcels of the terrestrial surface (including inland water) as belonging to various cover type categories (according to the classification scheme employed).

Land use

The economic or other human use of the land. It is often related to land cover but cannot be unambiguously derived from the knowledge of land cover alone.

Leaf area index

One half of the total projected green leaf area in the plant canopy per unit surface area (equivalent to one-sided leaf area for broad-leaf plants).

Light penetration

The extinction of light with depth within the water column of water bodies especially lakes.

Necromass

Dead plant biomass, mainly in plant litter at the soil surface or in standing plants (e.g., after forest fire).

Net ecosystem productivity

The total net annual uptake of carbon by the ecosystem, after all additions (photosynthetic assimilation) and losses (organic decay, plant respiration, grazing, and fires) have been accounted for.

Net primary productivity

The difference between the carbon uptake trough photosynthesis and release through plant respiration (both maintenance and growth respiration).

Peak leaf biomass of nitrogen fixing plants

The growing-season maximum leaf biomass of plants known to be associated with nitrogen-fixing organisms.

Permafrost active layer

The depth to the permafrost table.

Permafrost extent

The area of the permafrost detected within a defined depth increment.

Permafrost thermal state

The heat content of the permafrost and its structure with depth.

Plant tissue N and P content

The content of nitrogen and phosphorus in photosynthetic or structural tissues of plants.

Precipitation - accumulated (solid and liquid):

Definition to be provided by AOPC

Radiation - albedo

The ratio of the upwelling to the downwelling radiation at the surface.

Radiation-incoming short-wave

The amount of the incoming short-wave solar radiation at the surface.

Radiation - reflected short-wave

The amount of short-wave solar radiation reflected from the surface.

Radiation - fraction of photosynthetically active radiation (FPAR)

The proportion of the photosynthetically active solar radiation (400-700nm) which is absorbed by plant components containing chlorophyll.

Radiation - outgoing long-wave

The amount of long-wave radiation emitted by the earth’s surface.

Relative humidity (atmospheric water content near the surface)

The concentration of water vapour in the air near surface.

Rooting depth (95%)

The depth of soil which encompasses most of the live roots.

Roughness - surface

The three-dimensional structure of the interface between the surface (top of plant canopy or bare soil) and the atmosphere.

Snow cover area

The area of the land surface covered by snow.

Snow water equivalent (SWE) satellite

The amount of water stored as snow on the land surface.

Soil available phosphorus

The fraction of soil phosphorus that is in a chemical form from which it can be extracted by plants.

Soil bulk density

The mass of soil per unit soil volume.

Soil action exchange capacity

A measure of the soil’s chemical quality, specifically the ability to absorb and release ions.

Soil moisture

Water content in the soil within a specified depth, most often the plant root zone (1-2m).

Soil particle size distribution

The size distribution of the particles comprising the soil mineral matrix (often described in percent fractions of sand, silt and clay).

Soil pH

A measure of the concentration of hydrogen ions in the soil solution.

Soil surface state

A measure of the infiltration capacity of the soil for water at the surface. Can be expressed as infiltration rate or through surrogates such as the structure and roughness of the soil surface.

Soil temperature (subsurface)

Temperature at the specified depth(s) in the soil.

Stomatal conductance - maximum

The rate of exchange of the gases (H2O, CO2) between the interior of the leaf and the adjacent air outside the stomata leaf cells controlling the size of the opening).

Surface water flow - discharge

The amount of water flowing through a river channel cross-section per unit time.

Surface water storage fluxes

Change in the amount of water in surface reservoirs (lakes, artificial reservoirs, and wetlands). Requires simultaneous knowledge of area of the reservoir and the water level to determine the volume change.

Soil total carbon/nitrogen/phosphorus

The total amount of soil carbon/nitrogen/phosphorus.

Spectral vegetation greenness index

The ratio of reflectance from the plant canopy or its components in various spectral bands.

Temperature - air

Definition to be provided by AOPC

Topography

The characterization of the three-dimensional shape of the land surface.

Trace gas profile (CO2) - Lower troposphere

Definition to be provided by AOPC

Trace gas profile (HNO3) - Lower troposphere

Definition to be provided by AOPC

Trace gas profile (N2O) - Lower troposphere

Definition to be provided by AOPC

Volcanic sulphate aerosols

Definition to be provided by AOPC

Wind velocity

Definition to be provided by AOPC

Part 3. Specifications of Variables