Cloud Liquid Water Derived from Lidar Observations

The distribution of liquid water at the top of clouds has an important relation to the radiative and dynamical interactions within clouds. As a significant example, the formation and structure of marine stratus clouds are maintained primarily by radiative cooling at the cloud top. Understanding the formation of marine stratus is important climatalogically since the cloud type has a significant global influence on the balance between reflected visible and emitted thermal radiation. Models have shown that the interaction between radiative cooling and the cloud development are largley a function of the distribution of the liquid water at the cloud top. Although liquid water may be obtained from in situ measurements, only one dimensional observations are possible. Lidar liquid water observatios can provide a more complete two dimentional representation of the liquid water structure of cloud tops. In this contribution we will describe the lidar retrieval of cloud top liquid water during an experiment in which marine stratus clouds were studied by combined remote sensing and in situ observations.