Selected variables were derived from satellite images. These Earth Observation (EO) products were applied to carbon and water balance models, as input or for computing the models and for accuracy assessment. Sample products are shown below, first as static maps (click images to enlarge) then as interactive zoomable layers overlaid on geocoded basemaps.

Earth Observation products over the Boreal site

Stem basal area and biomass (total stem volume) on the boreal site - SuomiNPP data


Land cover (tree species) and leaf area index (LAI) on the boreal site - SuomiNPP data


Stem diameter and tree height on the boreal site - SuomiNPP data


Carbon and water balance maps from SuomiNPP and Sentinel-2

Boreal site Finland and Hyytiälä site

Mean Annual Increment: growth of the stem volume of the trees per hectare within a year. Evapotranspiration: the process by which water is transferred from the land to the atmosphere by evaporation from the soil and other surfaces and by transpiration from plants. Net Ecosystem Exchange: A measurement of the quantity of carbon entering and leaving the ecosystem. Net Primary Productivity: the amount of carbon uptake after subtracting Plant Respiration (RES) from Gross Primary Productivity (GPP), where GPP is the total rate at which the ecosystem captures and stores carbon as plant biomass, for a given length of time.

Mean Annual Increment (MAI) and Evapostranspiration (ET) on the boreal site based on SuomiNPP data


Net (NPP) and Gross (GPP) Primary Productivity on the boreal site based on SuomiNPP data


Net Ecosystem Exchange (NEE) in Finland based on SuomiNPP data - models for 2016 (left) and 2022 (right)


Net Ecosystem Exchange (NEE) in Hyytiälä (FIN), Sentinel-2 data - models for 2016 (left) and 2021 (right)


Mean Annual Increment (MAI) in Finland, 2016, based on SuomiNPP (left) and Sentinel-2 data (right)


Evapotranspiration in Finland based on SuomiNPP data - models for 2016 (left) and 2022 (right)


Evapotranspiration in Hyytiälä (FIN) based on Sentinel-2 data - models for 2016 (left) and 2021 (right)


Net Primary Productivity (NPP) in Finland based on SuomiNPP data - models for 2016 (left) and 2022 (right)


Net Primary Productivity (NPP) in Hyytiälä (FIN) based on Sentinel-2 data - models for 2016 (left) and 2021 (right)


Gross Primary Productivity (GPP) in Finland based on SuomiNPP data - models for 2016 (left) and 2022 (right)


Gross Primary Productivity (GPP) in Hyytiälä (FIN), Sentinel-2 data - models for 2016 (left) and 2021 (right)


North State - Earth Observation products

North State produced estimates from selected variables based on medium, high and very high resolution Earth Observation (EO) imagery. One of the most important data sources is the Sentinel satellites of the Copernicus programme. Sentinel-2 multispectral and Sentinel-1 radar imagery have been applied extensively - see for example Sentinel-1 mosaics from whole Finland in 20 m resolution on VTT EO data, tab "Map". Few UAV (Unmanned Aerial Vehicle) flight campaigns were carried you to collect additional data.

Variables

The most important variables to be estimated based on EO-data and applied in carbon and water balance models are:

  • Fraction of Absorbed Photosynthetically Active Radiation (fAPAR)
  • Leaf area index (LAI)
  • Forest area
  • Plant functional type (or tree species)
  • Tree height
  • Snow cover
  • Phenology: start and end of growing season
  • Logging events
  • Biomass (or growing stock volume)
  • Peatland extent

The rationale of the introduction of the EO based variables in the modelling comes from the need to calibrate the models and assess their accuracy. North State variables are demonstrated on the four intensive study sites at high resolution (20 m), and on the boreal site at medium resolution (200 m).


Land Cover and tree species (plant functional type)

Land cover classes that are applied in North State have been modified by using the FAO land cover class definitions as the starting point (FAO 2005).



Tree height

Tree height is calculated by some of the carbon models while others may require mean tree height as input. Stem basal area weighted average height will be applied in North State.



North State - carbon and water balance products

In North State the carbon and water products of interest are those which describe the state and the level of carbon, but are difficult, not retrievable, or have high uncertainty if they are attempted to estimate directly from EO data.

Net Ecosystem Exchange (NEE)

Net Ecosystem Exchange: The net carbon flux between an ecosystem and the atmosphere. Negative sign indicates an ecosystem acting as a net sink of carbon (removal of carbon from the atmosphere into the land) while a positive sign indicates an ecosystem acting as a net carbon source.

All the values are annual average for period 2000-2012.



Gross Primary Production and Mean Annual Increment

Below is presented Mean annual (2014) Gross Primary Production (GPP), which is the amount of carbon captured by photosynthesis. Mean annual increment (2014-2019)