Science

Carbon cycle: land, atmosphere & oceans

We want to understand regional carbon budgets and the feedbacks between the physical and biological processes involved in the carbon cycle.

Carbon is continually cycling between different natural stores on the Earth: atmospheric carbon dioxide is fixed by vegetation as it grows, it is absorbed by the oceans, and is released by combustion of fossil fuels or biomass fires. We want to understand the feedbacks between the physical and biological processes involved in the carbon cycle.

Atmospheric carbon dioxide is one of the main greenhouse gases driving climate change, so our ability to diagnose and estimate future levels of the gas in the atmosphere is crucial for climate prediction.

The carbon cycle is also important because it is integral to the food chain on which we depend. The rate at which plants draw down carbon affects the productivity of the whole planet. Understanding the links between climate and natural resources is an important challenge for the future.

Earth Observation has an increasingly important role to play in support of forest management. The Essential Climate Variables that relate to forest stocks are used by the Met Office and European Centre for Medium-range Weather Forecasts (ECMWF) for climate modelling, but also by the UN, national mapping agencies, and commercial companies providing services for the carbon market.

Our research priorities are:

  • To use EO data for models representing vegetation and its controls via carbon, energy and water exchanges, to improve our understanding, estimation and modelling of ecosystem productivity and energy exchange;
  • To develop an integrated approach to estimate global forest above-ground biomass and its dynamics, for model-testing and improvement, and to help constrain estimates of the terrestrial carbon cycle and the strength of climate feedbacks;
  • To estimate regional fluxes of carbon dioxide and methane from satellite observations and their sensitivity to climatic variations to help improve the representation of processes in land surface models;
  • To advance methods for quantifying fire disturbance – and in the longer term, pest disturbance – and its dynamic impact on ecosystems;
  • To improve ocean carbon fluxes from bio-geochemistry data assimilation, using EO data such as ocean SST and ocean colour.

 

 Our current work includes:
  • Using satellite observations combined with models of the land, atmosphere and ocean to quantify the movements of carbon around the planet – in particular the flows of carbon dioxide and methane – to understand the processes that drive them.
  • Estimating atmospheric concentrations of carbon dioxide and regional surface fluxes of carbon dioxide using data from satellites to learn more about the global carbon cycle.
  • Using EO data to track the planet’s land-based resources, using markers such as vegetation fluorescence and albedo to study forest health. NCEO researchers have created the first global map of vegetation height derived from the ICESat GLAS satellite. In Europe this dataset is used to forecast the risk that high winds pose for forests. Our‘albedo products are useful for NERC scientists and a variety of agencies, including the UK Met Office, where they are used to update land surface information in weather models, resulting in more accurate weather predictions and climate forecasts.
  • Supporting forest management by working with international partners such as the European Space Agency (ESA) to map global forest biomass stocks from optical and radar satellites that can ‘see through’ the cloud that often swathes tropical forests.
  • Integrating soil moisture and land surface temperature with forest data to derive fundamental parameters for land-surface models to improve their predictive ability.
  • Preparation for future missions that can better monitor the impacts of fire, deforestation and degradation. A proposal led by NCEO scientists for a purpose-built satellite to measure the carbon stored in the Earth’s forests was selected as the 7th ESA Explorer satellite: BIOMASS will be launched in 2020.
  • Providing ‘ground truth’ for new satellite products with Terrestrial laser scanning (TLS). This involves taking millions of laser measurements of a tree and combining them to build up a 3D picture of the tree with millimetre accuracy, enabling researchers to estimate the tree’s mass and thus its carbon storage.