Objectives
Interferometric Monitor for Greenhouse gases (IMG) aboard Advanced Earth Observing Satellite (ADEOS) is a Fourier Transform infrared (FT-IR) spectrometer which has been developed for measuring the greenhouse gases in the atmosphere, particularly in the troposphere. It was operated for about 7 months from November 1996 up to the end of the life time of the ADEOS on June 1997. The objective of this study is to develop new analytical methods which would be widely used in this field of data analysis for deriving the atmospheric gas concentrations from observed spectrum data and is to obtain the global distribution of the greenhouse gases for understanding the circulation system of the gases in the atmosphere.
Results
During the satellite operational period, IMG has measured about 15 global spectrum data sets. The results from retrieval analyses of the data for the stratosphere show the relationship between the ozone loss and temperature field over the arctic region in the northern hemispheric spring of 1997. Fig.1(a) and (b) respectively show the latitude-altitude displays of the zonally averaged temperature and ozone mixing ratio on April 2, 1997 when the most typical feature of arctic ozone loss was observed. These results show that relatively lower ozone concentration was observed in the colder (~200K) area appeared over the Arctic regions north of 60ºN. On the other hand, the preliminary analyses for the troposphere show that the methane concentration in the northern hemisphere was relatively higher than that in the southern hemisphere in the 1997 spring. Fig.2 is an example of the latitude-altitude display of methane concentration which was observed during a half satellite orbital cycle over the Atlantic Ocean on April 23, 1997.
