Estimating greenhouse gas emissions from space
Recognising the severity of the threat of climate change, European Member States ratified the Kyoto Protocol. As signatories, they must reduce their emissions of greenhouse gases, such as carbon dioxide (CO2). Estimating gaseous emissions over a region the size of the European Union is a difficult task. Scientists with the Koninklijk Nederlands Meteorologisch Instituut (KNMI) participating in the EVERGREEN project met this challenge by exploiting data from Earth-observing satellites. For example, data from the SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) aboard ENVISAT provided column measurements of methane (CH4), an important greenhouse gas. Data interpretation with inverse modelling techniques helped KNMI identify previously undetected sources of methane. This finding will greatly improve the accuracy of regional and global CH4 inventories. While KNMI was not as successful with CO2, it was able to make progress with carbon monoxide (CO), a precursor of CO2. This was made possible by data provided from the MOPITT (measurements of pollution in the troposphere) instrumentation on NASA's EOS Terra satellite. Finally, KNMI used data from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) and SCIAMACHY to enhance our knowledge of the Earth's radiation budget. They were able to resolve the complex set of chemical reactions governing the various sources and sinks that comprise the global methane budget. Based on its experience in the EVERGREEN project, KNMI has come up with several proposals for new satellite instruments that will enable better estimation of global CO2 emissions in the future.
