Satellite-borne sensors can provide us with very useful information on the climate change and global distribution of related materials. Aiming at global observation of greenhouse gases in the troposphere, the first satellite-borne sensor, Interferometric Monitor for Greenhouse gases (IMG), was developed as a sensor of the Advanced Earth Observing Satellite (ADEOS); it was launched in 1996 (the IMG project was funded by the Ministry of International Trade and Industry). We have obtained some global distributions of greenhouse gases from analysis of the IMG data. An example of the carbon monoxide distribution is shown in Fig. 1. Combining the satellite data and the four-dimensional assimilation technique, it is anticipated that studies on the behavior of greenhouse gases will progress greatly.

Figure 1: Global distribution of carbon monoxide column density retrieved from IMG data.