[OPTICAL REVIEW Vol. 7, No. 1 (2000) 95-100]

Signal Penetration into Thick Clouds Studied by Multi-Layer Data Observed with a Micro-Pulse Lidar

Wahyu WIDADA,1 Nobuo TAKEUCHI,1 Hiroaki KUZE,1 Akira TADAISHI1 and Shin SHIMAKURA2

1Center for Environmental Remote Sensing, 2Graduate School of Science and Technology, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba, 263-8522 Japan

(Received September 17, 1999; Accepted October 14, 1999)

Lidar return signals are studied for a micro-pulse lidar under sky conditions with multi-layer clouds. From theoretical considerations on the lidar signal-to-noise ratio, it is estimated that the maximum cloud optical thickness detectable is about 3.7. This result reasonably agrees with the actual multi-layer cloud data obtained from observations in Sukhothai, Thailand. Deviations from theoretical prediction, however, are found for a geometrically thin but dense cloud, and for a moderately concentrated but geometrically thick cloud. The effect of multiple scattering is also discussed.

Key words : lidar, penetration depth, optical thickness, multiple scattering, multi-layer clouds, Monte Carlo method