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 (595Kb)
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74,089,000 Yen (FY1997;20,642,000 Yen)
Earth-satellite-earth laser long-path absorption method for measuring atmospheric trace species was demonstrated with the Retroreflector in Space (RIS) on the ADE,OS, which was launched on August 16, 1996 by NASDA. In the initial experiments, optical characteristics of the RIS was evaluated and confirmed that it was working properly in orbit. The first atmospheric spectrum was measured with two TEA CO2 lasers based on the method using the Doppler shift caused by the satellite movement. Column contents of ozone was derived from the spectrum. It was validated by the simultaneous measurement with a laser heterodyne spectrometer. The operation of the ADEOS was discontinued, unfortunately, on June 30, 1997 due to the malfunction with the solar panel. To evaluate the measurement method and measurement system, measurement error was analyzed using the data taken with the RIS. It was found that the noise due to slight difference in the laser beam pattern of the two lasers were the !! cause of the error. Based on the analysis, the transmitter system and the satellite tracking system were improved. Characteristics of errors were also studied by comparing with the errors in the measurements with a corner-cube retroreflector installed on a tower 4 km away from the ground station. Because of the discontinuance of the ADEOS operation, we were not able to obtain sufficient data for atmospheric studies. However, we were able to demonstrate the measurement techniques for the first time, and we obtained useful data for the development of the next generation measurement system based on the earth-to-satellite laser long-path absorption method.
atmospheric trace gas, laser long-path absorption method, satellite retroreflector, RIS ADEOS