Products

Timeline Products

Within TIMELINE, a wide range of geoscientific products will be generated and provided to the public. The processing of these products follows a sophisticated series of individual steps, including pre-processing (calibration, chip matching, orthorectification), atmospheric and BRDF correction, cloud masking, and the generation of geophysical and thematic products on level 2 and level 3. All the processing steps are based on sound operational algorithms and will be documented and validated thoroughly.

The product range will include: Reflectance / Brightness Temperature, Surface Directional Reflectance, Surface Reflectance, Water masks, Snow and Ice, Land Surface Temperature (LST), the Normalized Difference Vegetation Index (NDVI), the Leaf Area Index (LAI), the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), the Fraction of Vegetation Cover (FVC), Fire Hot Spots, Burnt Area, Albedo, Cloud Coverage, Cloud Phase, Cloud Top Temperature, Cloud Optical Depth, Cloud Effective Radius and Cloud Water Path.

The table below gives an overview over the variables and further links.

Additionally, statistical information products will be produced from the bio-/geophysical or thematic variables such as temporal means or results of more complex analyses (e.g. start and end of snow cover).

Radiative variables of the Earth surface

TOA Reflectance / Brightness Temperature

TOA (Top Of Atmosphere) Reflectance is defined as the ratio between the radiant exitance and the irradiance at sensor level at the top of the Earth’s atmosphere. Delivered data is defined as technical albedo, with a value range of 0-100%. This data is sensor-specific, and is based on the NOAA-OSPO calibration. The technical albedos can be transformed to re-calibrated and sensor-invariant TOA reflectances using the TIMELINE harmonization tables. TOA Brightness Temperature is the temperature of a hypothetical blackbody (emissivity = 1). It is obtained by applying the inverse of the Planck function to the measured TOA radiance of a surface.

Surface Directional Reflectance (SDR)

Surface Directional Reflectance (SDR) is defined as the ratio between the radiant exitance and the irradiance at surface level. The value range of SDR is 0 - 1. SDR corresponds to atmospherically corrected TOA reflectances.

Surface Reflectance (SR)

Surface Reflectance (SR) is defined as the ratio between the radiant exitance and the irradiance at surface level accounting for BRDF effects. The value range of SR is 0 - 1.

Albedo

The Albedo is the ratio between the radiant exitance and the irradiance at surface level over the shortwave spectral domain (broadband). The value range of albedo is 0 - 1. Albedo is derived from the SR (Surface Reflectance) product. Albedo is an Essential Climate Variable (ECV) as recognized by the Global Climate Observing System (GCOS).

Land Surface Temperature (LST)

Land Surface Temperature (LST) is the mean radiative skin temperature of the land surface in the instrument’s field of view. It is derived from the thermal radiation as measured by the remote sensor. LST is an Essential Climate Variable (ECV) as recognized by the Global Climate Observing System (GCOS).

Land Surface

Water Mask

The Water Mask is a mask indicating pixels with are covered by water. Water bodies clearly below the pixel resolution are not detected by the algorithm.

Normalized Difference Vegetation Index (NDVI)

NDVI is an indicator for the “greenness” of vegetation and thus closely linked to vegetation density and productivity. The NDVI value can range from -1 to +1.

Leaf Area Index (LAI)

LAI is a quantitative measure of the amount of green leaves. It is a dimensionless variable, measuring the total one-sided area of green leaf area (in m²) per surface area (in m²). LAI is an Essential Climate Variable (ECV) as recognized by the Global Climate Observing System (GCOS).

Fraction of Absorbed Photosynthetically Active Radiation (FAPAR)

FAPAR is the fraction of photosynthetically active radiation which is absorbed by living green vegetation. FAPAR is an Essential Climate Variable (ECV) as recognized by the Global Climate Observing System (GCOS).

Fraction of Vegetation Cover (FVC)

The Fraction of Vegetation Cover (FVC) represents the fraction of land surface covered by vegetation.

Fire Hot Spots

The Fire Hot Spot product gives spatial and temporal information on the occurrence of active fires. Only large fires that are burning at the time of the satellite’s overpass are comprised in the dataset.

Burnt Areas

Product containing the extent of burn scars over a specified time period. Burnt Areas are detected due to reflectance changes caused by destroyed vegetation, ash and soot resulting from a fire.

Cryosphere

Snow and Ice

The Snow and Ice Mask indicates pixels which are covered by snow and/or ice.

Atmosphere

Cloud Mask

The Cloud Mask product maps and classifies pixels in a satellite image which are covered by clouds.

Cloud Products

The Cloud Fraction (CFC) indicates the fraction of a pixel that is cloud covered. The Cloud Phase (CP) indicates the phase of the cloud (water/ice). The Cloud Top Temperature (CTT) indicates the temperature of the uppermost cloud layer (in K). The Cloud Optical Thickness (COT) is the effective depth of a cloud from the viewpoint of radiation propagation and depends on wavelength. The Cloud Effective Radius (REF) provides the cloud effective particle radius. The Cloud Liquid/Ice Water Path (LWP/IWP) is the vertical integrated liquid water/ice content of existing cloud layers. The Precipitation Likelihood indicates where precipitation is likely. This product is only available for regions outside the tropics. Cloud Fraction, Cloud Top Temperature, Cloud Optical Thickness, Cloud Liquid/Ice Water Path (LWP/IWP) and Cloud Effective Radius are Essential Climate Variables (ECV) as recognized by the Global Climate Observing System (GCOS).