Concepts

Dry mass of living plant material above the soil surface, retrieved from spaceborne lidar (GEDI, ICESat-2), L-/P-band SAR (BIOMASS, SAOCOM,…

Properties of atmospheric aerosols including optical depth, single scattering albedo, size distribution, and vertical profile.

Surface-level mass concentration of particulate matter with diameter ≤ 2.5 micrometers.

Fraction of incident shortwave radiation reflected by the land surface, retrieved from MODIS, VIIRS, Sentinel-3 and PROBA-V BRDF inversions.

Anthropogenic emissions and removals of CO2, CH4 and N2O from fossil fuels, land use, agriculture and waste, inventoried by EDGAR, ODIAC, G…

Freshwater withdrawals and consumption by sector (agricultural, industrial, domestic), including irrigation extent and reservoir operations…

Compass direction the slope faces, expressed as degrees clockwise from north (0-360).

Surfaces with little or no vegetation cover: natural bare ground (desert, exposed rock, badlands), recently cleared agricultural land (post…

Depth of the sea floor below the sea surface (or geoid), expressed as positive-down meters.

Height of the planetary boundary layer (PBL) above the surface — the layer of the troposphere directly influenced by surface friction, heat…

Fractional (0-1) or binary coverage of built-up surface per pixel, capturing the spatial extent and morphology of human settlements.

Classified raster of fire impact derived from the differenced Normalized Burn Ratio (dNBR) and its relative form (RdNBR).

Per-pixel binary or fractional burned coverage detected from satellite imagery.

Height of the vegetation canopy above the underlying ground surface.

Atmospheric mole fraction of CO2 from surface flask network (NOAA GML), total/partial column from satellites (OCO-2/3, GOSAT, TROPOMI), and…

Chlorophyll-a concentration in inland water bodies (lakes, reservoirs, rivers, estuaries).

Per-pixel indication of cloud presence in an optical scene.

Cloud cover, top height/pressure/temperature, optical thickness, phase, effective radius and liquid/ice water path retrieved from passive a…

Multi-species abundance structure of an ecological community — counts, densities, or biomass of each species across a sampling event.

Above-ground vegetative biomass of a standing crop (dry-matter basis), observed by destructive sampling or estimated remotely from vegetati…

Developmental stage of a crop along its life cycle, typically encoded using the BBCH scale (germination, leaf development, tillering, flowe…

In-season identification of the dominant crop grown on a field, either as a class label or as a probability vector over a crop nomenclature.

Harvested production per unit area, typically reported at the subnational administrative level or estimated remotely at field scale.

Second derivative of the elevation surface — quantifies how the slope itself is changing.

Dissolved organic matter (DOM) - DOC, chromophoric DOM, and stable carbon isotopes (delta-13C).

Frequency, intensity, extent, and return interval of natural and anthropogenic disturbances — fire, windthrow, flood, insect outbreak, drou…

Elevation of the visible top surface — includes buildings, trees, and other above-ground features.

Elevation of the bare-earth surface — buildings, trees, and other above-ground features are removed (typically via LiDAR classification or …

Net balance of incoming solar and outgoing shortwave and longwave radiation at the top of the atmosphere.

Geographic extent and arrangement of ecosystem types — biomes, habitats, vegetation classes.

Seasonality of ecosystem-level fluxes and structure — start-of-season, peak-of-season, end-of-season and growing-season-length derived from…

Vertical structure of an ecosystem — canopy height, layering, foliage profile, basal area, and below-ground rooting depth.

The size of an idealised population that would lose genetic diversity (or experience drift) at the same rate as the population under study.

Height of the land surface above a vertical reference (typically the WGS84 ellipsoid or a regional geoid).

Abiotic water vapour flux from the land surface — evaporation from soil, open water bodies (lakes, rivers, wetlands), and intercepted water…

Combined surface water flux from soil/open-water evaporation plus plant transpiration.

Enhanced Vegetation Index — 2.5 * (NIR - Red) / (NIR + 6*Red - 7.5*Blue + 1).

Fraction of incoming PAR (400-700 nm) absorbed by the green vegetation canopy, derived from MODIS, VIIRS, Sentinel-3 OLCI and PROBA-V.

Vector geometry delineating an agricultural field (or management unit).

Active-fire detections, burned area and fire radiative power from MODIS, VIIRS and geostationary sensors (FCI, ABI, AHI).

Abundance, biomass, distribution, and size structure of marine fish populations.

Among-population genetic divergence, typically quantified through fixation indices (Fst, Gst, Jost's D) or differentiation across sampled l…

Within-population genetic variation, typically measured as allelic richness, observed/expected heterozygosity, or nucleotide diversity from…

Glacier area, length, elevation change and mass balance for mountain glaciers worldwide, from WGMS in-situ observations, the Randolph Glaci…

Groundwater levels and storage anomalies from monitoring-well networks and GRACE/GRACE-FO terrestrial water-storage retrievals.

Areal cover, growth form, and taxonomic composition of scleractinian (hard) corals on tropical reefs.

Date on which a crop was harvested, observed in situ or estimated remotely from greenness senescence.

Shaded relief computed from a DEM by simulating illumination from a light source at a specified azimuth and elevation.

Mass balance, surface elevation, surface velocity, grounding-line position and calving-front geometry of Greenland and Antarctic ice sheets…

Fraction (0-1) or percent (0-100) of a pixel covered by impervious artificial surfaces — roofs, asphalt, concrete, compacted material — thr…

The probability that two alleles at a locus in an individual are identical by descent, typically expressed as the inbreeding coefficient F …

Marine carbonate-system variables — DIC, total alkalinity, pH and pCO2 — from ship surveys (GO-SHIP, SOCAT), BGC-Argo pH floats and moored …

Structure and turnover of species interactions in a community — trophic links (predator-prey, herbivory), mutualisms (pollination, seed dis…

Abundance, biomass, and distribution of benthic and pelagic marine invertebrates - crustaceans, molluscs, echinoderms, and others.

Indicator of whether and how a field is irrigated - rainfed, surface, sprinkler, or drip.

Lake water extent, level, surface temperature, ice cover and ocean-colour analogue water-leaving reflectance, from satellite altimetry, opt…

Classification of the terrestrial surface into thematic classes (forest, cropland, grassland, urban, water, etc.), following the UN-FAO LCC…

Radiometric (skin) temperature of the land surface from thermal-infrared satellites (MODIS, VIIRS, SLSTR, ECOSTRESS, LST mission).

Turbulent exchange of latent (evaporation) and sensible heat between land surface and atmosphere, measured by eddy-covariance towers (FLUXN…

One-sided green leaf area per unit ground surface area, retrieved from MODIS, VIIRS, Sentinel-3 OLCI, PROBA-V and Sentinel-2.

Efficiency with which absorbed photosynthetically active radiation (APAR) is converted into fixed carbon by vegetation.

Lightning flash density and discharge characteristics from ground-based detection networks and space-borne optical sensors.

Fraction of ground covered by living vegetation (FCOVER) or, more generally, by living organisms forming the dominant structural layer of a…

Areal cover, canopy structure, and species composition of large benthic macroalgae - kelp forests and fucoid assemblages.

Areal extent, canopy structure, biomass, and species composition of mangrove forests.

Distribution, abundance, and composition of anthropogenic marine debris - macro-plastics, microplastics, and other litter - across the surf…

Extent and condition of foundational marine habitats: coral reefs, seagrass meadows, mangroves, kelp forests and macroalgal beds.

Abundance, distribution, movement, and demography of marine megafauna - turtles, seabirds, cetaceans, and pinnipeds.

Atmospheric mole fraction of CH4 from the surface flask network and total-column retrievals (TROPOMI, GOSAT, MethaneSAT, EMIT).

Biomass, abundance, and genomic diversity of marine bacteria, archaea, and viruses.

Body-size and shape traits of individuals (e.g.

Active displacement of individuals through space — migration paths, home-range geometry, dispersal distances, and behavioural state derived…

Normalized Difference Vegetation Index = (NIR - Red) / (NIR + Red).

Rate of net carbon fixation by primary producers — gross primary productivity minus autotrophic respiration.

Upwelling top-of-atmosphere radiance observed at night, captured by the VIIRS Day/Night Band (Suomi-NPP, NOAA-20/21) and historically by th…

Dissolved N2O concentration and ocean-atmosphere N2O flux.

Capacity of an ecosystem to retain and cycle nutrients (primarily N and P) rather than lose them to surface or groundwater.

Concentrations of dissolved inorganic nutrients in seawater - primarily nitrate, phosphate, and silicate.

Pressure at the ocean bottom, indexing the integrated ocean-mass column above.

Water-leaving radiance and derived bio-optical products from satellite ocean-colour sensors (SeaWiFS, MODIS, VIIRS, OLCI, PACE) — chlorophy…

Dissolved N2O concentration and air-sea flux, measured by ship surveys and autonomous platforms (MEMENTO database).

Dissolved inorganic macronutrients in sea water (nitrate, phosphate, silicate), measured by ship hydrography and BGC-Argo nitrate sensors.

Dissolved oxygen concentration in sea water from Biogeochemical-Argo floats, ship hydrography (GO-SHIP) and moorings.

Ambient underwater sound levels, including natural soundscapes and anthropogenic noise (shipping, sonar, construction).

Net heat flux across the air-sea interface, comprising sensible, latent, shortwave and longwave components.

Wind-driven momentum flux at the ocean surface, derived from scatterometer winds or in situ measurements.

Atmospheric abundance of long-lived greenhouse gases other than CO2 and CH4, including N2O, SF6, halocarbons (CFCs, HCFCs, HFCs, PFCs) and …

Dissolved molecular oxygen concentration in seawater.

Stratospheric and tropospheric ozone abundance and vertical profile from Dobson/Brewer networks, ozonesondes and UV/IR satellite sounders.

Suspended particulate matter - particulate organic carbon (POC), particulate inorganic carbon (PIC), and particle flux.

Ground temperature in boreholes and active-layer thickness from CALM and GTN-P networks, complemented by satellite-derived permafrost exten…

Occurrence, severity, and spatial extent of crop pests and diseases on a field.

Timing of recurring life-cycle events such as leaf-out, flowering, fruiting, migration, breeding, and emergence.

Physiological traits and tolerances of individuals (e.g.

Standing stock and community composition of marine phytoplankton - biomass (chlorophyll-a, carbon), functional types, and species diversity.

Phytoplankton and zooplankton biomass, abundance and community composition, from Continuous Plankton Recorder, imaging-flow cytometry, eDNA…

Grid-based count of resident or ambient population per pixel/cell.

Liquid- and solid-phase water falling from the atmosphere to the Earth's surface, including rain, snow, sleet and hail.

Reactive precursor gases that control secondary aerosol and ozone formation: NO2, SO2, HCHO, CO, NH3 and volatile organic compounds.

Bit-packed per-pixel quality flags shipped as the `QA_PIXEL` band of Landsat Collection 2 Level-2 surface-reflectance products (LSDS-1619 D…

Elevation expressed relative to the water surface of a nearby river, rather than relative to sea level.

Reproductive traits including age at first reproduction, fecundity, clutch or litter size, breeding success, and reproductive phenology.

Volume flow rate of water through river cross-sections, from in-situ gauges (GRDC) and satellite altimetry/SWOT-derived discharge.

Per-pixel scene classification shipped as the `SCL` band of Sentinel-2 Level-2A products.

Extent, concentration, thickness, drift and age of polar sea ice from passive microwave (SSMIS), altimetry (CryoSat-2, ICESat-2), SAR and v…

Height of the sea surface relative to a geodetic reference or tide gauge benchmark, from satellite radar altimetry (TOPEX/Jason/Sentinel-6)…

Surface wave field characterised by significant wave height, period and direction, from satellite altimetry, SAR, moored buoys and SWIM.

Horizontal velocity of the ocean surface from satellite-derived geostrophy plus Ekman, HF radar, surface drifters and Doppler scatterometry…

Salinity of the near-surface ocean from Argo floats, drifters, thermosalinographs and L-band radiometry (SMOS, SMAP, Aquarius).

Temperature of the upper ocean (skin, sub-skin or bulk depending on retrieval), from satellite IR/microwave sensors, drifting buoys, ships …

Areal extent, percent cover, and species composition of seagrass meadows.

Rate of biomass production by heterotrophs — herbivore, detritivore, and carnivore consumption converted to body tissue.

Rate of change of elevation with horizontal distance, expressed as degrees from horizontal (0-90) or percent rise.

Snow cover extent, snow depth and snow water equivalent (SWE) from passive microwave, optical satellites (MODIS, VIIRS) and in-situ network…

Stocks of soil organic and inorganic carbon, mapped from point profiles (WoSIS), digital soil mapping (SoilGrids) and emerging hyperspectra…

Volumetric water content of the surface and root-zone soil from L-band radiometry (SMOS, SMAP), C-band scatterometry/SAR (ASCAT, Sentinel-1…

Soil chemical fertility indicators - pH, organic carbon, cation exchange capacity, and available macronutrients (N, P, K).

Date on which a crop was sown or planted in a field, observed in situ or estimated remotely from greenness onset.

Number of individuals (or estimated density) of a species in a defined area over time.

The geographic range or area of occupancy of a species, derived from occurrence records, range maps, or species-distribution models.

Three-dimensional velocity beneath the ocean surface from moored ADCPs, lowered ADCPs on hydrographic sections, gliders and float-derived d…

Salinity profile beneath the ocean surface from Argo, deep Argo, ships and moorings.

Temperature profile beneath the ocean surface from Argo floats, deep Argo, ships, moorings (TAO, RAMA, PIRATA) and XBTs.

Temperature of the air near the surface, conventionally measured at 1.25-2 m above ground over land and at standard heights over ocean.

Horizontal velocity of seawater at the ocean surface, typically resolved as eastward and northward components.

Atmospheric pressure at the Earth's surface, typically reduced to mean sea level for synoptic analysis.

Net balance of incoming and outgoing shortwave and longwave radiation at the Earth's surface.

Bottom-of-atmosphere (BOA) reflectance — the proportion of incoming solar radiation reflected by the Earth's surface, per spectral band, af…

Momentum flux from the atmosphere to the land surface (wind stress over land), derived from scatterometer winds and reanalysis.

Water vapour content of the near-surface atmosphere, expressed as specific or relative humidity, dew point or vapour pressure.

Horizontal wind speed and direction near the Earth's surface, typically at 10 m over land and ocean.

Species richness and related diversity metrics (Shannon, Simpson, evenness, Hill numbers) summarising the taxonomic composition of a commun…

Difference between a pixel's elevation and the mean elevation of its neighbourhood.

Distribution and dispersion of functional traits (e.g.

Anthropogenic tracers used to date water masses and quantify ventilation timescales: CFC-11, CFC-12, SF6 and tritium/3He.

Mean absolute difference in elevation between a pixel and its immediate neighbours, expressed in meters.

Water clarity / suspended-sediment proxy.

Vertical profile of air temperature through the troposphere and stratosphere from radiosondes, GNSS radio-occultation and satellite sounder…

Vertical profile of water vapour in the troposphere and stratosphere from radiosondes, hyperspectral IR sounders and microwave/limb instrum…

Vertical profile of horizontal wind speed and direction through the troposphere and stratosphere, from radiosondes, aircraft, and Doppler w…

Physiological response of vegetation to adverse conditions — drought, heat, nutrient deficiency, disease, pest pressure.

Binary or multi-observer visibility raster derived from a DEM and one or more observer points.

Per-pixel indication of surface water presence.

Abundance, biomass, and diversity of zooplankton communities, including copepods, krill, gelatinous taxa, and ichthyoplankton.