Invitation to Tender: Land surface carbon constellation study

Carbon is a constituent of all terrestrial life.

Carbon begins its cycle through different ecosystems when plants assimilate atmospheric CO2 through photosynthesis into reduced sugars.

One of the biggest unknowns in carbon cycle research concerns the land component of the carbon system. The uncertainties in both pools and fluxes of CO2 are high and the basic understanding of the different processes involved in the amplitude and variability of the sinks and sources of the land carbon reservoir is still poor.

In the coming few years, the advent of the ESA missions BIOMASS (aimed at providing information on Above Ground Biomass) and FLEX (aimed at measuring vegetation fluorescence from space as an indicator of photosynthetic activity) will break new ground on land carbon research. The synergic capabilities of both missions together with SMOS, Sentinels and non-European novel observations from space (e.g., NISAR,GEDI) will open up new vistas to address some of the most pressing questions in carbon science directly.

However, observations and model simulations need to be combined in order to (1) enhance our process understanding, (2) quantify fluxes and pools and (3) estimate the remaining uncertainties. Generating coherent information across a wide range of temporal and spatial scales (maps without gaps) requires substantial advancement of our observing systems, our modelling capabilities, and our ability to integrate observations and models in a physically consistent way.

The activity aims at preparing the exploitation of future satellite observations together with numerical models for a better understanding and quantification of the land component of the terrestrial carbon cycle.

Three dedicated activities will be addressed:

1) A benchmark data set representing the measurements available in the future shall be collected, provided to the community, and analysed. At super-sites spanning different biomes a suite of instruments including tower-based remote sensing and in-situ will be deployed and operated for an extended period of time. Measurements at these super sites shall support the development of models, data assimilation, product retrieval algorithms, and the verification of models and satellite observations.

2) Carbon models shall be advanced in order to be able to exploit the new information that will be available from current and future satellites. The development of advanced models shall target a more realistic representation of ecosystem processes at an adequate model resolution that is needed to minimize sampling and representation mismatch with observations. The models should be suitable for operation in single column mode using the observations obtained at the selected super sites.

3) Combining models and observations in a physically consistent way requires new data assimilation systems including forward operators for the different observing systems. The benchmark data set together with the advanced models shall be used to develop and test the analysis system. The techniques and models tested in single column mode shall then be applied at regional scale.

Learn more about this Invitation To Tender on the EMITS page.