Decreasing uncertainties in the regional contributions to the global carbon cycle with state-of-the-art Earth observation products

Carbon fixation via photosynthesis is known as gross primary production (GPP), and together with ecosystem respiration it dominates the land-atmosphere exchange of carbon dioxide (CO2).

It is thus one of the main processes driving climate regulation, carbon sequestration and storage as well as being important for a range of ecosystem services, including the production of food, feed, fiber, fuel, biodiversity and the regulation of the habitability of Earth.

Given the central role of GPP within the Earth system and within climate change mitigation, accurate monitoring from space is pivotal.

Within the global carbon cycle research community, modelling with Earth observation is generally using two approaches; 1) bottom-up approaches with physical relationships based on ground observation applied on global scale, or 2) or top-down approaches where processes within terrestrial biosphere models are constrained to fit the Earth observations.

Recently, it was shown that the mismatch between the two approaches matches the global carbon budget imbalance, highlighting key needs in improved understanding in the reasons for this mismatch.

The Copernicus Sentinel fleet is a series of next-generation Earth observation missions, and the main aim with the proposed project is to bring the data from the Sentinel fleet into the two main Earth observation approaches for studying global carbon cycling.

The project is separated into two different research questions: 1) What is the impact of increasing the spatiotemporal averaging resolution of input Earth observation data for the GPP variability as estimated by empirical light use efficiency upscaling methods? 2) Can we decrease the difference in the spatiotemporal variability within the global-scale estimates of GPP of the top-down and bottom-up approaches by using state-of-the-art Earth observation products?

Results and knowledge gained during this project will increase our understanding of the processes driving climate regulation and carbon sequestration, and increase our capability to predict environmental changes.

This enhance the possibilities to make informed decision makings, being of high relevance for many of the UN sustainable Development Goals.