Signal penetration into thick clouds studied by multi-layer data observed with a micro-pulse lidar

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