Frequency-doubled CO_2 lidar measurement and diode laser spectroscopy of atmospheric CO_2

A lidar instrument based on pulsed frequency-doubled carbon-dioxide lasers has been used at 4.88 μm for remote sensing of atmospheric carbon dioxide. A tunable-diode laser spectrometer provided the high-resolution spectroscopic data on carbon-dioxide line strength and line broadening needed for an accurate differential absorption measurement. Initial field measurements are presented, and instrument improvements necessary for accurate carbon dioxide measurement are discussed.