Sampling CO2 levels by satellite

Posted by mjs76 at Apr 08, 2011 10:23 AM |
Leicester academic explains how technology in orbit boosts global climate change data.

Discussion of atmospheric carbon dioxide levels and their effects on climate change tends to concentrate on fossil fuel emissions - from industry, transport, power generation etc. But that only accounts for about two thirds of carbon emissions; the rest comes from agriculture, forestry and other changes in land usage.

Planet Earth Online, the web magazine of the Natural Environment Research Council, has a feature on this subject and how satellite technology is used to measure land usage emissions, co-written by Dr Hartmut Bosch from our Department of Physics and Astronomy.

With colleagues from Edinburgh, Dr Bosch looks at how satellite observation enables scientists to study areas of the globe previously difficult to reach but hugely important in the emission and natural capture or ‘sequestration’ of CO2. Land- or air-based measurements mostly cover Europe, North America and the oceans, omitting vital carbon capture areas such as tropical forests and sub-Arctic tundra.

Sequestration currently compensates for just over half of human-caused CO2 emissions, absorbing the carbon back into terrestrial ecosystems, so a full, detailed picture of the extent of those ecosystems – and how they are changing – is essential when calculating and predicting climate change data.

The first satellite specifically designed to measure CO2 levels in the troposphere (the lowest part of the atmosphere) was the Japanese spacecraft GOSAT (Greenhouse gasses Observing SATellite - pictured) launched in 2009. A contemporary NASA satellite called OCO failed to reach orbit but a replacement, OCO-2, is scheduled for launch in 2013.

Dr Bosch and his colleagues conclude that:

To address concurrently the science and policy questions that require knowledge of carbon fluxes on a wide range of temporal and spatial scales, and with limited financial resources, we must strive both for improved ground-based networks and for satellite systems with denser and more frequent sampling over the regions we know least about.”