Examples of dynamic processes within the bio-, geo-, cryo- and hydrosphere and the observation intervals required for their systematic monitoring. GCOS (Global Climate Observing System) defined the essential climate variables (ECV) in 2010 (www.wmo.int/gcos)

Owing to its novel imaging techniques and its great acquisition capacity, Tandem-L will deliver urgently required information for the solution of pressing scientific questions in the domain of the bio-, geo-, cryo- and hydrosphere. In this way, Tandem-L contributes significantly to a better understanding of the Earth system and its dynamics. Important mission goals are:

  • the global measurement of forest biomass and its variation in time for a better understanding of the carbon cycle,
  • the systematic monitoring of deformations of the Earth’s surface on a millimetre scale for the investigation of earthquakes and risk analysis,
  • the fine scale measurement of variations in the near-surface soil moisture as well as observations of the dynamics of ocean surfaces and ice drift as well as
  • the quantification of glacier motion and melting processes in the polar regions.

This will allow Tandem-L for the first time, to measure simultaneously seven essential climate variables in a single satellite mission. Following scientific key questions will be addressed with Tandem-L.

  1. How large is the amount of biomass stored in the forests of the Earth, and what is its spatial distribution, considered in various scales of resolution?
  2. How are the biomass and the structure of forests changing over time? Where and to what extent are these changes taking place? Where are the hotspots of anthropogenic deforestation?
  3. How do climate change and anthropogenic disturbance impact the structure and stability of forests? Where does disturbance take place, and how quickly is it spreading?
  1. Is it possible to measure the build-up of stress along plate boundaries (at scales >> 1000 km²) and to improve the forecast model for a particular earthquake?
  2. Where is the fracture zone of an earthquake located, and what is its size? How much energy is accumulated prior to the earthquake, and how much of it is released during the earthquake and the subsequent phase of relaxation?
  3. Is it possible to use measurements of surface deformation to predict danger in volcanic regions? How are volcanoes connected to their environment?
  1. How do the spatial and temporal dynamics of soil moisture contribute to soil and plant transpiration? How does this affect the exchange of water and energy between the soil and the atmosphere?
  2. How do soil moisture patterns influence the formation of new ground water, surface run-off and soil water storage in moderately large river basins?
  3. How strong is the link between spatiotemporal changes in soil moisture and changes in regional climate (and weather)?
  1. How is climate change impacting glaciers and ice caps? Which mechanisms cause this change, and how can they be better assessed?
  2. Which processes are driving the current mass depletion in the major ice sheets? How can the uncertainties in determining mass changes be reduced?
  3. How is global climate change altering the sea ice drift and the deformation patterns in the Arctic and Antarctic? What methods can we use to improve modelling of internal forces and to obtain better sea ice forecasts?