A Global Greenhouse Gas Monitor

We present an advanced new sensor, the Greenhouse Gas Monitor (GGM), which will revolutionize the global measurement of greenhouse gas levels. The GGM is an ideal compact, passive instrument for deployment on future-generation small LEO satellites. The Kyoto summit on greenhouse gas and carbon emissions has demonstrated the urgent need for accurate, global monitoring of a range of greenhouse gases. Levels are currently estimated by making precise ground-based measurements at a few points around the world; coverage of the Earth’s surface can be vastly improved by making measurements from space along a closely spaced grid. We are developing an advanced tuneable etalon spectrometer, tuned to the near infrared bands (1.2 to 1.7 μm), which will scan the reflected sun-glint on the Earth’s surface and measure CO2 absorption spectra and atmospheric column amounts. In addition to the primary Greenhouse gas, carbon dioxide, the GGM can also measure the column amounts of methane (CH4), water vapour and oxygen. The instrument will scan a swath width of 400km with a grid spacing of 50km and provide about 1000 samples per month on a 8° x 10° grid. The target standard error in monthly averages is about 0.3% corresponding to about 1ppm CO2.