Future perspective
The laser long-path absorption method between the ground and a satellite is one of the most sensitive remote sensing techniques for measuring concentration of atmospheric trace species. Though global coverage is not obtained with this method, it can play a unique role in the measurement of trace species especially in the troposphere where passive satellite sensors are not necessarily useful.
A laser long-path absorption method using a detection system on a geosynchronous satellite is being studied as a tropospheric trace gas monitoring system in the future. In this system, low power pulsed laser beams are transmitted from ground stations to the geosynchronous satellite, and laser beams are received at the satellite. With this system, column contents of trace species above the ground stations are measured continuously as long as the weather permits. Large tracking telescopes are not required at the ground station. Also, the laser power required for the measurement is much smaller than that for the RIS experiment. Consequently, the ground system can be much smaller than the ground system for the RIS experiment. Narrow band tunable infrared lasers are the key technology to realize this method, because the Doppler shift method which was used in the RIS experiment is not useful with a geosynchronous satellite.
9. Publications
1. Outline of the RIS Experiment
2. The RIS on the ADEOS
3. Ground system for the RIS experiment
4. Results - Active tracking using image of the RIS
5. Results - Optical characteristics of the RIS
6. Results - Spectrum Measurement with the RIS
7. Results - Orbital Determination of ADEOS by laser ranging to the RIS
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